Assessment Summary Sheet for UKAB Meeting on 13 November … Manuals and... · ICAO Risk ERC Score...

Assessment Summary Sheet for UKAB Meeting on 13th November 2013

Total Risk A Risk B Risk C Risk D Risk E

16 0 9 4 1 2

Airprox Reporting (Type)

Reported (Type)

Airspace (Class) Cause ICAO

Risk ERC

Score

2013040 PA28(1) (Civ Trg)

PA28(2) (Civ Club)

Gloucestershire ATZ (G)

The PA28(2) pilot flew into conflict with PA28(1).

B 20

2013052 RJ1H (CAT)

B206 (Civ Comm)

London/City (LCY) CTR (D)

The Thames controller allowed the B206 to fly into conflict with the RJ1H Contributory: Lack of coordination by Thames Radar and LCY.

B 102

2013058 PA38 (Civ Club)

Cirrus SR22 (Civ Trg)

Hawarden ATZ (G)

The SR22 pilot flew into conflict in the visual circuit with the PA38, which he did not see.

C 4

2013059 ASK13 (Civ Club)

C182 (Civ Pte)

Wycombe ATZ (G)

A possible non-sighting by the C182 pilot and an effective non-sighting by the ASK13 pilot. Recommendations: 1. The BGA Instructors’ Panel reviews gliding activity at Booker. 2. Wycombe reviews procedures for powered and glider traffic integration in the ATZ. 3. The CAA reviews the education of GA pilots regarding overall awareness of gliding operations with specific emphasis on flight in the vicinity of glider sites.

B 20

2013061 Do328 (CAT)

PA34 (Civ Trg)

Dundee ATZ (G)

Having been told he was No.2 in the pattern, but in the absence of effective TI, the Do328 pilot turned into conflict with the PA34. Contributory: 1. Leuchars did not coordinate the right-hand base join with Dundee. 2. Insufficient TI from ATC regarding the PA34. 3. The Dundee controller was distracted by non-operational tasks. 4. Use of ambiguous reporting points. 5. Lack of questioning of TI by the Do328 pilot.

C 10


Reported (Type)


Risk ERC

Score

2013070 B777 (CAT)

Typhoon FGR4 (HQ Air Ops)

UAR UL602 (C)

A perceived conflict by the Montrose Sector controller. Contributory: 1. One of the Typhoons exceeded 8000fpm rate of climb in CAS. 2. The Boulmer Weapons Controller assumed that the B777 would remain in level flight. 3. The UCCS display mechanisation did not allow for display of destination, and did not facilitate ready display of Mode S.

E 1

2013071 Tucano T1 (HQ Air Trg)

Socata TB20 (Civ Pte)

Vale of York AIAA (G)

The Linton controller descended the Tucano pilot into conflict with the TB20. Contributory: 1. Both pilots were under an inappropriate ATS for their flight conditions. 2. The TB20 pilot was not in contact with Linton LARS. Recommendations: 1. The CAA reviews the education of ATSOCAS and specifically the benefits of DS in IMC, and that the MAA address this same issue through each Front Line Command. 2. The CAA and MAA review the adequacy of guidance for provision of level allocation to pilots under a TS. 3. The MAA reviews harmonisation of MMATM and CAP413 phraseology.

B 4


Reported (Type)


Risk ERC

Score

2013072 ASW20 Glider

(Civ Club)

Aquila A210 (Civ Trg)

Lon FIR (G)

The A210 pilot flew over a promulgated and active glider site, below the notified winch-launch altitude, and into conflict with the ASW20, which he did not see. Recommendations: 1. The CAA reviews annotation of gliding RTF on VFR charts and the AIP ENR5.5. 2. The CAA reviews the education of GA pilots regarding overall awareness of gliding operations with specific emphasis on flight in the vicinity of glider sites.

B 20

2013073 Vigilant T1 (HQ Air Trg)

PA28 (Civ Pte)

Lon FIR (G)

A non-sighting by the PA28 pilot of the Vigilant that he was overtaking. Contributory: Lack of timely TI from the Lakenheath controller. Recommendation: Lakenheath reviews their RT nomenclature and ATS provision.

B 100

2013076 C152 (Civ Trg)

PA28R (Civ Club)

Stapleford ATZ (G)

The PA28 pilot flew close enough to cause the C152 pilot concern.

C 2

2013077 Vigilant T1 (HQ Air Trg)

PA28 (Civ Pte)

Lon FIR (G)

A non-sighting by the PA28 pilot.

C 4

2013079 PA42 (Civ Comm)

Nimbus 2C (Civ Pte)

Lon FIR (G)

A conflict of flight-paths resolved by the PA42 pilot. Recommendation: The BGA Competition Committee reviews content of glider competition NOTAMs and promulgation of daily task notification.

B 20

2013080 MD902 (Civ Comm)

C172 (Civ Pte)

Lon FIR (G)

A late sighting by both pilots, resolved by the MD902 pilot. Recommendation: National Police Air Service reviews the equipping and employment of TCAS (and P-FLARM) in Police Helicopters.

B 20

2013081 Sea King (HQ Air Ops)

Tornado GR4 (HQ Air Ops)

LFA 14 (G)

A non-sighting by the GR4 pilot.

B 101


Reported (Type)


Risk ERC

Score

2013086 A320 (CAT)

Unknown Lon UIR (C)

Sighting report. D N/S

2013100 RJ1H (CAT)

R44 (Civ Pte)

London/City CTR (D)

Although well clear of the other aircraft, and with it in sight within Class D airspace following appropriate TI from ATC, the R44 flight vector generated a TCAS RA in the RJ1H. Recommendation: The CAA reviews TCAS interaction between local traffic and CAT inbound and outbound LCY.

E 1

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AIRPROX REPORT No 2013040 Date/Time: 19 May 2013 1438Z (Sunday)

Position: 5154N 00210W (Gloucestershire A/D)

Airspace: Gloucestershire ATZ (Class: G)

Reporter: Gloucestershire ADC

1st Ac 2nd Ac

Type: PA28(1) PA28(2)

Operator: Civ Trg Civ Club

Alt/FL: 200ft NK QNH (NK) NK

Weather: VMC CLBC NK

Visibility: >10km NK

Reported Separation:

100ft V/100m H NK

Recorded Separation:

NK

CONTROLLER REPORTED

PART A: SUMMARY OF INFORMATION REPORTED TO UKAB

THE GLOUCESTERSHIRE ADC reports that he cleared the PA28(1) pilot for T/O from the in-use RW27. He had conducted a scan of the RWY and departure track to the NW prior to issuing the clearance. As PA28(1) climbed out, the pilot asked whether Gloster knew about an ac ‘approximately 1 mile west’ of the A/D, opposite direction, which the pilot had made a turn to avoid. The ADC looked out to the W and advised PA28(1) that he could not see any other ac, and had no other known ac airborne in that direction. He looked further L towards the SW and observed another ac in a R turn, approximately half a mile from the A/D. The ac proceeded to land on RW09 without clearance and vacated to park. The fire crew were alerted and assisted the ac to parking. The ADC removed himself from the operational position and went to meet the pilot. In discussion with the pilot it was clear that he had mistakenly been in communication with Shobdon [EGBS]; he had been receiving a service from them but was convinced that he had been speaking to Gloucestershire [EGBJ]. Shobdon ATC had advised of their runway in use, which was RW09 and which was reciprocal to the runway in use at Gloucestershire. The pilot also stated that he had misplaced his knee board and when looking at his chart misread ‘EGBS’ for ‘EGBJ’, therefore tuning to the wrong RTF. THE PA28(1) PILOT reports conducting an instructional sortie with a student. He was operating under VFR in VMC in receipt of an ACS from Gloster TWR [122.900MHz]. The white and red ac had navigation lights and rotating beacon selected on, as was the SSR transponder with Modes A and C. The ac was not fitted with an ACAS. On T/O from RW27, the student reported seeing another ac ahead. The instructor initially assumed it to be another departing ac but almost immediately realised that no ac had taken off ahead of them, and in fact this ac was on a reciprocal heading. The student initiated a turn to the R, as per noise abatement procedures; the instructor elected to take control at that point to ensure that separation was maintained and to allow the student to regain composure. During this turn he looked back towards the A/D and saw the conflicting ac on short final for RW09. At this point he was advised to contact APP [128.550MHz] and he contacted ATC to inform them of

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the situation he had just witnessed. He initially stated that the conflicting ac was about 0.5nm from him but this was erroneous. His best estimation was that the two ac were no more than 100m apart at the closest point, but due to the noise abatement procedures he did not believe there was an imminent risk of collision, although the potential for such was substantial. He assessed the risk of collision as ‘None’. [UKAB Note(1): The UK AIP entry for Gloucester A/D noise abatement procedures, at AD 2.EGBJ-10 sub-paragraph (d), states:

‘Departures Runway 27 - All departing aircraft are to execute a 10° right turn when passing the upwind end of the runway. Tracking 280 MAG, climb through 600ft QFE before turning left. Avoid over flight of the village and church on the right. Jet aircraft are to climb through 1400 ft QNH before executing any turn. Aircraft unable to comply with 10° turn after takeoff should advise ATC and climb straight ahead through 1400 ft QNH.’]

THE PA28(2) PILOT declined to file a report. ATSI reports the Airprox occurred at 1438:28, 0.5nm to the SW of Gloucestershire A/D, within the Class G airspace of the Gloucestershire (Gloster) ATZ, between PA28(1) and PA28(2). Background The PA28(1) pilot was departing from Gloster RW27 for a local VFR flight to the NW and was in receipt of an ACS from Gloster TWR [122.900MHz]. The PA28(2) pilot was operating on a VFR flight inbound to Gloster from Sleap A/D, had mistakenly selected the incorrect RTF and was in communication with Shobdon Information [123.500MHz], in receipt of a BS. Gloster ATSU, were providing a split Aerodrome and Approach Control Service from the VCR without the aid of surveillance equipment with RW27 in use. The Shobdon FISO’s workload was assessed as moderate with RW09 in use. CAA ATSI had access to RTF recordings for Gloster APP and Shobdon Information, together with area radar recording, written reports from the Gloster Aerodrome Controller, Shobdon FISO and the PA28(1) pilot. No written report was received from the PA28(2) pilot. The Gloster Airport weather was recorded as follows: METAR EGBJ 191420Z 30004KT 240V350 9999 SCT045 18/07 Q1013= Factual History At 1421:09, the PA28(2) was 29.3nm N of Gloster displaying an SSR code 0010 to indicate that the pilot was monitoring Birmingham RTF. The PA28(2) was not displaying Mode C level reporting. At 1430:22, the PA28(2) was 9.8nm NNW of Gloster (25.2nm SE of Shobdon) when the SSR code was changed to 7000. The PA28(2) pilot made an initial call to Shobdon Information [123.500MHz], “Gloster Tower [PA28(2) C/S]”. The Shobdon FISO’s written report indicated that there was an intervening call from another ac. The Shobdon FISO reported that the call received from the PA28(2) pilot was unclear and of readability 3 to 4 with added difficulty due to a strong foreign accent. [ATSI Note: The quality of the recorded RTF from the PA28(2) pilot was distorted, of readability 2-3 and was very likely to have been degraded due to the 25nm range of the ac from Shobdon and the ac’s level]. The Shobdon FISO continued to pass instructions to other ac. At 1432:10, the PA28(2) was 5.8nm NNW of Gloster and the pilot called Shobdon Information again, “Gloster Information [PA28(2) C/S]”. The FISO indicated receiving part of the C/S and in response transmitted, “Station calling Shobdon information say again your callsign”. The PA28(2) pilot replied, “It’s [PA28(2) C/S] er Piper Arrow er inbound to yourself six miles to the northwest er at er three

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thousand feet er will be joining overhead er for runway two seven right hand”. The Shobdon FISO responded “[PA28(2) C/S] it’s Runway zero nine right hand Q F E one zero zero one”, which was acknowledged by the PA28(2) pilot, “Q F E one zero zero one f or zero niner runway righthand [PA28(2) C/S]”. At 1433:36, the PA28(2) was 3.2nm northwest of Gloster. The PA28(2) pilot then routed towards the O/H, passing to the N of the A/D. He reported, “[PA28(2) C/S] overhead descending on the deadside to join righthand for zero nine to land”. The Shobdon FISO replied, “[PA28(2) C/S] roger report downwind”. At 1434:50, the PA28(2) pilot reported, “[PA28(2) C/S] downwind for zero nine” and the Shobdon FISO replied, “[PA28(2) C/S] er traffic is one Cessna one five two er late downwind”. The PA28(2) pilot’s reply was unreadable. The Shobdon FISO’s written report indicated that the PA28(2) was not seen downwind so the assistant was asked to scan the downwind leg. Nothing was seen. At 1435:08, the Shobdon FISO called the PA28(2) with no response. This was followed by two further calls with no response. Meanwhile, the PA28(1) pilot at Gloster A/D was at the holding point ready for a departure from RW27. At 1436:21, the Gloster TWR issued take off clearance, “[PA28(1) C/S] clear for take off with a right turn to the northwest surface wind three four zero degrees less than five”. At 1436:28, the PA28(2) was shown on radar downwind RH for Gloster RW09. As the PA28(1) was rolling the PA28(2) was shown turning onto R base for RW09, 1.4nm SW of Gloster. At 1438:00 the PA28(2) was shown on short final for RW09. The PA28(1) did not appear on radar until 1438:42, after the Airprox has occurred, after the PA28(1) pilot made a R turn and tracked W. By using the radar recording and projected flight path history, it was estimated that the Airprox occurred at 1438:28, shortly after the PA28(1) pilot became airborne. The PA28(2) was estimated to have passed less than 0.1nm to the S of the PA28(1), on a 0.5nm final for RW09. The PA28(1) pilot’s written report estimated that the PA28(2) was to his L and below and estimated the horizontal distance between the two aircraft as 100m at the CPA. At 1438:07, the PA28(1) pilot was instructed to contact Gloster APP [128.550MHz]. He replied, “Er [PA28(1) C/S] contact approach we just saw and aircraft coming along the zero nine ahead of us er any update on that traffic”. The Gloster TWR responded, “Er no I’ve got nothing here erm at all”. This was acknowledged by the PA28(1) pilot, “Roger”. The Gloster TWR asked the PA28(1) pilot if he knew the ac type; the PA28(1) pilot replied “er negative but I think he has touched-down on zero nine”. At 1438:59, the PA28(2) pilot called Gloster TWR, “and [PA28(2) C/S] Gloster”. There was no response to this call and was likely not heard by the Gloster TWR. The Gloster TWR first responded to the PA28(1) pilot, “and [PA28(1) C/S] yeah apologies for that he’s not actually speaking to anybody and erm has just landed er sorry sorry for that”. The PA28(2) pilot vacated the runway and parked on the Apron. The PA28(1) pilot reported, “er [PA28(1) C/S] we just did a slightly evasive manoeuvre that’s all er we’ll contact approach now one two two decimal eight er we’ll go to one two eight decimal five five”. The Gloster TWR advised the PA28(1) pilot that the other ac had not spoken to Gloster APP either and in response the PA28(1) pilot reported it was most likely to be a suspect radio failure. The PA28(1) pilot then changed to Gloster APP. The Shobdon FISO became increasingly concerned at the loss of contact with the PA28(2) pilot and D & D were advised. A subsequent call from Gloster confirmed the arrival of the PA28(2) at Gloster and Shobdon then updated D & D. The Aerodrome controller’s written report indicated that, when questioned, the PA28(2) pilot had reported that when looking at his chart he had misread EGBS (Shobdon) for EGBJ (Gloster) and

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selected the wrong frequency, contacting Shobdon for an ATS instead of Gloster. Shobdon had advised him that RW09 was in use, which was reciprocal to RW27 in use at Gloster. Analysis The PA28(2) pilot, when looking at his chart, mis-identified EGBS as Gloster, which resulted in the him calling Shobdon instead of Gloster. It is likely that because of a combination of the distance from Shobdon and the foreign accent of the pilot, the quality of the PA28(2) transmissions was readability 2-3. The PA28(2) made two initial calls “Gloster Tower” and then “Gloster Information”. However, the quality of the transmission made the calls unclear and consequently these were not heard by the Shobdon FISO. The Shobdon FISO’s workload was moderate and he tried to establish two way communication with the unknown ac. The FISO transmitted “Station calling Shobdon information say again your callsign” and the pilot responded “It’s [PA28(2) C/S] er Piper Arrow er inbound to yourself six miles to the northwest er at er three thousand feet er will be joining overhead er for runway two seven right hand”. At the point when two way communication was established the FISO correctly used the callsign ‘Shobdon Information’, however this was not detected by the PA28(2) pilot who replied “..inbound to yourself..”. The pilot very likely assumed that he was talking to Gloster TWR. The PA28(2) pilot entered the Gloster ATZ in the belief that he was cleared to join overhead Gloster for a RH cct on RW09. This resulted in him flying into conflict with the PA28(1) which was departing from RW27. The PA28(2) was not observed by the Gloster TWR who was unable therefore to pass any TI or warning to the PA28(1) pilot. The Shobdon FISO gave the PA28(2) pilot appropriate joining instructions and TI in the belief that he was inbound to Shobdon. Summary The Airprox occurred when the PA28(2) pilot mis-identified Shobdon RTF for Gloster RTF and then selected the incorrect frequency for a join at Gloster. The PA28(2) pilot entered the Gloster ATZ in the belief that he had been cleared to join overhead for a RH cct on RW09, which resulted in him making an approach to RW09 and coming into conflict with the PA28(1), departing from RW27. The Gloster TWR and Shobdon FISO were not aware of the PA28(2) pilot’s intentions and were unable to provide appropriate information to either of the two ac concerned.

PART B: SUMMARY OF THE BOARD'S DISCUSSIONS

Information available included a report from the pilot of one of the ac, a transcript of the relevant RT frequency, radar video recordings, reports from the air traffic controllers involved, and a report from the appropriate ATC investigation authority. Members first discussed the actions of the PA28(2) pilot and were in agreement that his sortie could have been planned and flown with more care. It was opined that although his confusion over the Shobdon and Gloster RTFs could be considered as an ‘honest mistake’, it was a mistake that had serious ramifications and which could have been effectively mitigated by better preparation. Members were at a loss as to how the 2 airfields could be confused on the map: Shobdon and Gloucester are surrounded by significantly different topography, which is clearly depicted on the map, and each A/D’s RTF is printed in the same area as the A/D’s name (in Shobdon’s case, directly above the A/D name). Members noted that Gloucester A/D does not have a signal square, but opined that once he had arrived in the overhead the pilot had time to observe the wind sock direction and to remain in the overhead and observe other traffic if necessary. That being said, the PA28(2) pilot was faced with a situation that appeared to fit his mental model, given that Gloster had a RW09 and he thought he had been cleared to join. Some pilot Members opined that given his range from Shobdon the RT was probably distorted and broken, which might have given the PA28(2) pilot an indication that he was not near the station he was speaking to, although in the absence of an RT recording this remained conjecture. ATC Members also noted that the PA28(2) pilot prefixed his first

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2 transmissions with a Gloster C/S; in the event, the Shobdon FISO did not assimilate this, probably due to the quality of RT. Likewise, the PA28(2) pilot may not have been able to make out the initial use of C/S by the Shobden FISO, which was not repeated. Notwithstanding the quality of R/T reception, Members noted that this incident served as a useful reminder, highlighting the reasoning behind the requirement not to respond to a C/S other than your own. Some Board Members were of the opinion that this report could not be assessed due to the lack of information from the pilot of PA28(2). Whilst he did not submit a report, it was felt by the majority that enough information had been captured from other sources such that a reasonable assessment of the incident could be reached. The PA28(1) pilot had just taken off and although initially confused by the aspect of the head-on PA28(2) flying into conflict with him, quickly assimilated the situation and remained clear of collision, albeit in the Board’s opinion more by good fortune in conducting the noise abatement manoeuvre, and with safety margins much reduced below the normal. The Board agreed that the safety barriers pertinent to this Airprox were ATC/FISO rules and procedures, controller action, aircrew rules and procedures, visual sighting, aircrew action and SA gained from RT. The Board concluded that ATC/FISO rules and procedures had been effective but that controller action had no effect because the Gloster controller was unaware of PA28(2)’s presence, and the Shobden FISO had been under the impression that the ac was inbound to his airfield. Aircrew rules and procedures and SA gained from RT were not effective, and visual sighting and aircrew action had limited effectiveness. The barriers were assessed overall as being of minimal effectiveness and the Airprox was allocated a score of 20 on the Event Risk Classification Matrix.

PART C: ASSESSMENT OF CAUSE AND RISK

Cause

: The PA28(2) pilot flew into conflict with the PA28(1).

Degree of Risk

: B.

ERC Score:

20.

1

AIRPROX REPORT No 2013052 Date/Time: 22 Jun 2013 1126Z (Saturday)

Position: 5131N 00001E (1.5nm W London/City A/D- elevation 16ft)

Airspace: London/City CTR (Class: D)

Reporting Ac Reported Ac

Type: RJ1H B206

Operator: CAT Civ Comm

Alt/FL: 1200ft 1500ft QNH QNH

Weather: VMC CLAC VMC CLOC

Visibility: NK ˃10km


100ft V/150m H Not seen


200ft V/0.5nm H

PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE RJ1H PILOT reports departing runway RW27 at London City squawking SSR Modes S and C. The aircraft was climbing to 3000ft in strong wind, which was creating moderate turbulence and shifting wind direction. At approximately 600ft agl TWR informed him about traffic crossing the RW27 axis ahead. At 800ft agl a TCAS TA was received and visual contact established with a blue and white helicopter (believed to be a JetRanger) at one o’clock, less than 200m away, about 100ft higher. Due to the short distance from the helicopter, pitch was reduced to 5° (speed increased to 150 KIAS, no flap over-speed due to fast reaction). Everything happened within less than 5 seconds. Afterwards normal clean-up was performed. He reported the minimum vertical separation as 100ft and horizontal as 100-200m. He considered the severity of risk as high. THE B206 LONGRANGER PILOT reports operating under SVFR, he thought, with clearance from Heathrow Radar on frequency 125.625MHz (see UKAB Note(1) below). The predominantly blue helicopter had SSR Modes S and C selected. He was heading 360°, speed 100kt at 1500ft, in VMC, with flight visibility and horizontal distance from cloud as over 10km. To the best of his knowledge he had been cleared from London Bridge, via the Isle of Dogs Visual Reporting Point, to leave the Zone to the N. From his experience he was usually instructed to hold at London Bridge or the Isle of Dogs if there was traffic at London City. Additionally, he was often transferred to London City TWR (118.075MHz) for onward clearance. As far as he could remember he had not been instructed to hold or given any clearance limit. Heathrow issued an avoiding action descent to altitude 1000ft during the incident. He did not see the RJ1H. An ACAS was not fitted. [UKAB Note(1): The helicopter was operating on a VFR clearance at the time of the Airprox.]

THE LONDON CITY TWR/GROUND CONTROLLER reports that, as the RJ1H was rolling, he observed, on the ATM, an un-coordinated helicopter that (he realised) had previously been transferred to Heathrow SVFR heading along route H4 into London. He observed the helicopter out of the window but did not pass traffic information (TI) as the departure was beyond the point of stopping safely. Whilst the SUP contacted SVFR he used the priority line to inform the SVFR controller that a

Diagram based on radar data

B2061400ft alt

CPA 1146:47200ft V 0.5nm H

A08

NM

0 1

46:23

46:35

46:11

45:5945:47

A12

1145:35

RJ1H

T/O 1146:11

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departure was rotating. He visually observed that the aircraft were not going to collide. He added that he could not turn the RJ1H N because it would have prolonged the risk Also, he could not stop its climb due to the proximity of high buildings. The pilot reported visual with the helicopter, adding he thought it was dangerous. Subsequently, the pilot reported on RTF that he had stopped the climb at 1400ft, with the helicopter 300ft above. The controller visually assessed that the helicopter had cleared the climb out before the departure stopped climbing. THE LTC THAMES RADAR/SVFR CONTROLLER reports that there were two airways aircraft airborne and approximately four General Aviation aircraft on frequency, either on the heli-lanes or flying in the London City (LC) zone. The B206 (VFR helicopter) had been handed back to him by LC TWR travelling W to Vauxhall Bridge. LC TWR had called him and informed him that an RJ1H was the last departure before airport closure. His perception of this exchange was that the RJ1H in question was an aircraft just airborne (same company as the subject aircraft), and as such there would be no further departing LC traffic to affect VFR aircraft. After this call he cleared the B206, a VFR helicopter, to route eastbound via the Isle of Dogs and Lee Valley to leave controlled airspace northbound. This routed him through the climb out of LC RW27, approximately 2nm W of LC. As this helicopter was passing through the climb out the LC priority line rang and upon answering, the TWR informed him there was departing traffic airborne. TI and a descent to not above 1000ft was given to the B206. Both aircraft reported visual; however, the pilot of the subject RJ1H informed him subsequently that he had had to deviate from the SID as a result of this. Factual background MATS Part 1 states: ‘Separation standards are not prescribed for application by ATC between VFR and IFR flights in Class D airspace’1. The London City weather was:

METAR EGLC 221120Z 21019KT 9999 SCT022 SCT040 17/11 Q1005=

Analysis and Investigation

CAA ATSI

CAA ATSI had access to written reports from both pilots, the London City Tower controller, the Thames Radar controller, area radar recordings, RTF recordings and transcripts of London City Tower frequency, Thames/SVFR frequency and desk-side telephone calls. ATSI also interviewed both the London City Tower controller and the Thames Radar controller.

The London City controller was operating AIR and GMC combined (London City). The Thames Radar controller was operating Thames and SVFR combined (Thames). London City Airport was open beyond usual operating hours and, in accordance with normal practice, was due to close 15min after the last aircraft movement.

The Thames controller plugged in at approximately 1115 with the position already band-boxed. At interview, the controller reported that the frequency was busy but that the traffic was reasonably straightforward and he was anticipating that the situation would become significantly easier when London City closed, which was due to happen shortly.

At 1130:00 Thames spoke to the London City Supervisor on the telephone and ascertained there were no more arrivals and 5 departures pending before London City closed.

1 MATS Part 1, Chapter 5, Paragraph 5.3

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At 1141:20 the B206, which had previously been operating on the London helicopter routes, reported back on frequency with Thames (from London City) as it was passing London Bridge routeing westbound on helicopter route H4. The B206 was instructed to route westbound and was given a clearance limit of Vauxhall. The B206 pilot informed Thames that he would be turning at Vauxhall to return eastbound and the B206 was given a return clearance limit of London Bridge.

At 1141:40 the London City Supervisor telephoned Thames stating that “our last one’s just backtracking to line-up now”. During this telephone call another helicopter, not involved in the Airprox, called Thames and the controller recalled the Battersea telephone line ringing. Thames thanked London City and hung-up. At interview the Thames controller reported that he believed that London City had said “that’s the last one”. At 1141:53 the penultimate departure from London City, an aircraft that was not directly involved in the Airprox, became visible on radar (the Thames Radar controller believed that this was London City’s last movement prior to official close fifteen minutes later).

At 1143:31 Thames cleared the B206, “eastbound again hotel four to the Isle of Dogs to leave the zone northbound not above two thousand VFR”. The Thames controller stated, at interview, that, as he believed that movements at London City had finished, and in a bid to reduce his workload by avoiding having to reissue a clearance, he cleared the B206 to leave the zone to the N, which would require crossing the London City RW27 climb-out.

There was a pending departure strip for the RJ1H and the Departure Status Information display indicated that the RJ1H was still to depart but the Thames controller had not noticed either. Strips are usually delivered 5-10 minutes before departure by an assistant. When London City closes, departure checks (which require London City to request a radar release from Thames prior to giving take-off clearance to departing aircraft) are automatically put in place in anticipation of the first movement the following morning. As Thames believed that London City had no more movements he had placed the ‘check’ strips in the relevant bays, indicating that Thames had control of the airspace (effectively indicating that departure checks were on). London City, having not received an instruction to impose departure checks, had no reason to request a radar release from Thames before departing the RJ1H.

At 1143:20 the RJ1H pilot informed London City that he would need another 2 minutes before departure. The RJ1H was instructed to report ready. A fixed-wing aircraft was transiting the London City Zone to the S. London City was aware that this had not been co-ordinated but was not overly concerned as it was a callsign the controller was familiar with and he was aware that the flight would operate to the S of the airport. Earlier in the day Thames had co-ordinated traffic remaining outside the London City Zone, which had subsequently entered the Zone without further co-ordination. The London City controller stated that, had the traffic been another squawk, he would have contacted Thames to obtain details on it. London City passed TI to the RJ1H on the fixed wing to the S and issued take-off clearance to the RJ1H. At 1145:20 the take-off clearance to the RJ1H had been read back and the B206 was NW of the Isle of Dogs, tracking SE (Figure 1).

4

Figure 1.

As the RJ1H became airborne the London City controller looked at the ATM, preparing to transfer the RJ1H to Thames and observed that the B206, instead of following the river to the Isle of Dogs, appeared to have ‘cut the corner’ and was closer to the London City climb-out than expected. The London City controller was concerned about the position of the B206 and commented to a colleague that if the B206 turned N the situation would be difficult (although it was merely an observation - he had no expectation that the B206 would turn N. The B206 had conducted several flights during the course of the morning and, in common with other helicopters operating on H4 that morning, had often spent a few minutes operating over the city S of the Isle of Dogs before continuing onward).

At 1146:22, having observed that the B206 was, in fact, tracking N (Figure 2), London City initiated a telephone call on the priority line to Thames to co-ordinate avoiding action.

Figure 2

The London City controller reported being confident in general about giving avoiding action but in this particular instance he felt that he had no options available – turning S would bring the RJ1H into proximity with tall buildings while turning N would exacerbate the confliction with the B206.

5

Instructing the RJ1H to stop the climb, considering the subsequent inertia, had the potential to increase the conflict with the B206, particularly as the London City controller was unaware of the intentions of the B206. When the telephone was answered, London City asked Thames what the B206 was doing as the departing RJ1H was “going straight at him”. At 1146:29 the departing RJ1H became visible on radar (Figure 3). Thames replied with some alarm that “...you didn’t tell me about that one...” before informing London City that the B206 was going N.

Figure 3.

During the course of the telephone conversation the London City controller, who could see both aircraft out of the window, realised that the helicopter would pass ahead of the RJ1H. With hindsight the London City controller believed that TI to the RJ1H would have assisted the crew’s situation awareness; however, at the time, his focus was on co-ordinating action with Thames to avoid a collision.

Thames instructed the B206 to descend to 1000ft and passed TI on the departing RJ1H. The Thames controller expected that the RJ1H would be at 1500ft and climbing when it reached the position of the B206 and with limited options available to him chose to issue descent instructions in an attempt to ‘cross levels’ and resolve the confliction.

At 1146:37 the RJ1H informed London City that they had the helicopter in sight (Figure 4). London City replied that unknown traffic had just passed ahead in front. The RJ1H replied, “traffic in sight continue”.

6

Figure 4.

The RJ1H passed behind the B206. CPA was 0.5NM/200ft (Figure 5).

Figure 5. SUMMARY

The Thames controller was busy when London City telephoned and one other aircraft called whilst the telephone call was being conducted. It is likely that Thames misheard London City due to a combination of being distracted by the other tasks and the other aircraft calling at the same time, making the telephone call more physically difficult to hear. Thames was also expecting, and hoping for, a telephone call from London City to say they were closing, which may have predisposed him towards the misunderstanding. When the London City Supervisor informed Thames that the last aircraft was backtracking, neither controller referred to an aircraft callsign, so the identity of the aircraft actually being described was unclear. When the London City controller observed the fixed wing traffic to the S he did not query the lack of co-ordination with Thames as he was familiar with the callsign and the standard operating route of the flight. As Thames had not fully co-ordinated previous traffic through the London City Zone, the London City controller thought that Thames had forgotten to

7

co-ordinate the fixed-wing; whereas Thames actually believed that London City’s movements had finished and therefore there was no requirement to co-ordinate. The London City controller commented that, had it been another aircraft, he would have queried the routeing and lack of co-ordination, which may have alerted the Thames controller to his misunderstanding that London City was in the process of closing. The Departure Status Information indicated that there was another departure prior to London City closing. The departure strip for the RJ1H was in the pending strip bay but the controller had not noticed it. It is likely that the strip had been placed in the bay prior to the telephone call that led the Thames Radar controller to believe that London City were in the process of closing the airport, following the last aircraft movement. It is also likely that his conviction that London City were closing, in combination with the other strips indicating that he had control of the airspace, contributed to him overlooking the information that indicated otherwise. PART B: SUMMARY OF THE BOARD’S DISCUSSIONS Information available included reports from the pilots of both aircraft, transcripts of the relevant RT frequencies, radar video recordings, reports from the controllers concerned and reports from the appropriate ATC and operating authorities. The Board quickly came to the conclusion that the Airprox had occurred because the Thames controller, believing that London City (LCY) airport had closed, had cleared the B206 pilot to cross its RW27 climb-out lane as the RJ1H was departing the airfield. Much of the ensuing discussion was focused on why this had occurred. With regard to the Thames controller, a civil Terminal Control member explained that the Thames ATC display would have shown that LCY had not closed, that there would have been a pending departure strip for the RJ1H, and that the Departure Status Information display would have shown that the RJ1H was still to depart. Not only had the Thames controller apparently not assimilated this information but, additionally, believing that the airport was closed, the controller had placed ‘check’ strips in the relevant bays in preparation for the first movement the following day. At the time, the controller was performing the combined tasks of Thames/SVFR. As it was a busy period, the Board wondered whether the positions should have been split. The ATSI advisor commented that, with hindsight, this might have been appropriate; however, the workload was expected to reduce very shortly after London City had closed and so it was not unreasonable for the two tasks to have been combined. The Board then turned its attention to the co-ordination between LCY and the Thames controller. They considered that the co-ordination should have been more positive. Neither the LCY Supervisor (who had carried out the co-ordination) nor the Thames controller referred to an aircraft callsign during the co-ordination process; doing so might have highlighted the fact that the last flight of the day had not yet departed. Additionally, it was suggested that the LCY controller’s call of, “our last one’s just backtracking to line-up now”, had allowed the Thames controller to form the conclusion that the aircraft he saw on his radar display shortly afterwards was that last departure , when it was in fact the penultimate departure. If LCY had positively waited until the last aircraft was airborne before speaking to Thames then any ambiguity would have been removed. Turning to the LCY Tower controller, a Board member wondered whether the Tower controller should have noticed the presence of the B206 on the Air Traffic Monitor before clearing the RJ1H for take-off. However, radar recordings show that, when he passed the RJ1H’s take-off clearance, the helicopter was still tracking SE towards the Isle of Dogs and not towards the airport and so was not a factor at that time. Finally, a civil helicopter pilot member wondered whether the B206 pilot had looked out towards LCY as he was crossing the airport’s climb-out lane to check if there were any aircraft departing or about to depart. No mention had been made about this in the B206 pilot’s report, but the pilot member considered that this would have been good operating practice in any case, even if the B206 pilot had been told that LCY was closed.

8

Discussion then took place about whether the risk should be classified as a Category B or C. Some Members opined that, because the RJ1H pilot had reportedly observed the helicopter 200m away, and had in fact remained at least 0.5nm from it, the classification should be Risk C (no risk of collision). However, the majority agreed that the circumstances of the event meant that the RJ1H pilot had had very little time to react and few options available to him to manoeuvre; even though he had taken action by levelling off in the very short time available after visual contact, the incident had still resulted in safety margins being much reduced below the normal. PART C:ASSESSMENT OF CAUSE AND RISK Cause: The Thames controller allowed the B206 to fly into conflict with the RJ1H. Degree of Risk: B. Contributory Cause: A lack of coordination by Thames Radar and LCY. ERC Score2: 102

2 Although the Event Risk Classification (ERC) trial had been formally terminated for future development at the time of the Board, for data continuity and consistency purposes, Director UKAB and the UKAB Secretariat provided a shadow assessment of ERC.

1

AIRPROX REPORT No 2013058 Date/Time: 21 Jun 2013 1740Z

Position: 53 10N 002 58W (Hawarden Aerodrome)

Airspace: Hawarden ATZ (Class: G)


Type: PA38 Cirrus SR22

Operator: Civ Club Civ Trg

Alt/FL: 900ft 1500-1800ft QFE (1007hPa) NK

Weather: VMC CLBC VMC N/R

Visibility: N/R N/R


200ft V/200m H N/R V/N/R H


N/R V/0.2nm H


THE PA38 PILOT reports flying VFR in a predominantly white aircraft, squawking Mode 3/A 7010 with no Mode C fitted. He was in contact with the Hawarden Tower controller, performing touch and go circuits on RW04RH with a s tudent, when he heard the SR22 pilot call on the radio for taxi instructions. He perceived that the other pilot was having difficulty understanding the Tower controller. Whilst on final approach, he saw the SR22 waiting at a holding point and, following his touch-and-go, he heard the SR22 pilot being given clearance to take off whilst keeping the PA38 in sight, he thought. The PA 38 pilot was conscious that the SR22 has a significantly better performance than his aircraft, so he r esolved to keep a c areful look-out for it and r eports that his aircraft has a rear window he was able to use. On reaching 500ft he turned on to the cross-wind leg and, as he approached the downwind turning point, he noticed that the SR22 pilot had turned cross-wind inside of his circuit; he instructed his student to level off at 900ft. Tower tried to contact the SR22 pilot 3 times to check if he could see the PA38, but the PA38 pilot did not hear a response. He then saw the SR22 pass 200ft ‘directly over the top’ of his aircraft. Following the Airprox, he had a telephone conversation with the SR22 pilot, who said that he had been too busy trying to see the PA38, with the assistance of his TCAS, to respond to the radio. He assessed the risk of collision as ‘High’. THE SR22 PILOT reports that his aircraft was displaying strobe, landing and navigation lights; he had the transponder with Mode C switched on but does not recall the Mode 3/A code. He planned a VFR departure from RW04 and recalls being ‘cleared for take-off, right turn, not above 1500ft’. On turning right he was ‘alarmed by TAS traffic’ but could not see the other aircraft. H e was aware that the PA38 pilot was ‘watching’ his aircraft and he kept his aircraft in ‘straight flight’ whilst continuing to look for the other aeroplane, but he did not see it at any point. During the telephone conversation, he recalls that the PA38 pilot told him that he had maintained visual contact with the SR22 from the point it took off, and that the Airprox had occurred at around 1100ft. THE TOWER CONTROLLER reports that the weather was good with little cloud and e xcellent visibility. The PA38 was flying a training sortie with multiple visual circuits to RW04RH when the SR22 pilot called for start on t he ‘Northern Apron’. The controller tried to establish the SR22’s

CPA 1740:23-410.2nm H

PA38NMC

SR22

Hawarden ATZ

Diagram based on radar dataand pilot reports

NM

0 1 2

F015

F014

2

endurance; it took several transmissions and t he controller felt that the pilot was having ‘difficulty understanding the language’. Furthermore, the controller had to read the clearance more than once before the pilot read it back correctly. When the SR22 reached Hold-Point Delta (displaced approx 400m from the threshold) the pilot requested departure. The Controller was unsure if the SR22 pilot would want to back-track to the threshold and, with the PA38 on base-leg along with the language difficulties, he decided to instruct the SR22 pilot to ‘Hold’ on Taxiway Delta. Taxiway Delta is angled towards the approach giving the SR22 pilot a good opportunity to see the PA38 making its approach. Once the PA38 had passed the intersection with Taxiway Delta, the Controller instructed the SR22 pilot to line-up and w ait. H e then passed traffic information about the PA38 to the SR22 pilot, followed by a clearance to take-off; the SR22 pilot acknowledged the clearance and, he thought, the traffic information too. The controller monitored both aircraft and, when it seemed clear that the SR22 was going to ‘position nicely behind the PA38’, he turned his attention to controlling tasks related to an inbound aircraft, which was around 10nm away. Tower heard the PA38 pilot transmit that he was visual with the SR22 flying closely behind his aircraft and tried to contact the SR22 pilot three times to check that he had visual contact with the PA38. After the third attempt, the SR22 pilot responded to Tower and the PA38 pilot reported that the aircraft were now clear of each other. Factual Background The prevailing meteorology recorded at Hawarden at the time of the Airprox was: METAR EGNR 211720z 34002KT 9999 FEW025 SCT035 18/13 Q1009= Hawarden circuits are notified as right hand at 1000ft QFE, elevation is 45ft1

.


CAA ATSI reports that it had access to reports from the PA38 and SR22 pilots, a report from the Hawarden controller, recorded area surveillance and t ranscription of the Hawarden Tower frequency.

RW04RH was in use; the PA38 had been conducting VFR touch-and-go circuits since 1705, in receipt of an Aerodrome Control Service from Hawarden Tower. The SR22 had just departed on a VFR flight, in receipt of an Aerodrome Control Service from Hawarden Tower. At 1726:06 the SR22 pilot called Tower, “request er taxi instructions departure ????? south through Welshpool (SR22 c/s) is apron November.” Tower instructed the SR22 pilot, “taxi holding point Delta via taxiways November Juliet Alpha and Delta for runway 04.” The SR22 pilot replied, “taxi and to hold point Delta via Juliet Alpha Delta.” The PA38 pilot reported final for touch and go at 1727:34; Tower gave the surface wind and cleared the PA38 for a touch-and-go. At 1731:21 Tower instructed the SR22 pilot, “if you continue along taxiway Alpha vacate correction turn left onto taxiway Delta for holding point Delta.” The SR22 pilot replied, “er taxiway to holding point Delta just wanted to warm up.” The SR22 reported at holding point Delta at 1733:56 and informed tower, “ready for departure.” Tower instructed the SR22: Tower: “hold at holding point Delta, after departure right hand turn out V F R not above altitude one thousand five hundred feet squawk 4 6 0 1” SR22: “squawk er 4 6 0 1 er right er hand turn holding at Delta”

1 UK AIP AD 2.EGNR-9 (10 Jan 2013).

3

Tower: “that is correct not above altitude one thousand five hundred feet though on departure” SR22: “two thousand five hundred er after dep- the departure” Tower: “it’s not above one thousand five hundred feet” SR22: “stay at altitude one thousand five hundred.” The PA38 pilot reported turning for right base at 1734:49 and was instructed to report final. Tower then instructed the SR22 pilot to hold position due to an aircraft (the PA38) turning final in the circuit. This was acknowledged by the SR22 pilot. The PA38 pilot reported final for touch and go at 1736:24 and Tower gave the surface wind and cleared him for a touch-and-go. At 1737:03 the following exchange took place between Tower and the SR22: Tower: “(SR22 c/s) will you require backtrack on departure” SR22: “Er (SR22 c/s) repeat please” Tower: “(SR22 c/s) via Delta runway zero four backtrack as required line up and wait” SR22: “Er runway zero four line up and wait (SR22 c/s)” Tower: “And (SR22 c/s) the PA38 just touched and goes remaining in the right hand visual circuit runway zero four, clear for take-off surface wind light and variable” SR22: “Clear for take-off (SR22 c/s) right turn (SR22 c/s)”. Tower then transmitted to the PA38 pilot “SR22 about to depart runway zero four with a right hand turn out VFR”. He replied, “copied that plane.” The Tower controller subsequently recalled that he w atched the SR22 on c limb-out and was visual with both aircraft as the PA38 flew crosswind. The controller reported that the visibility was very good and that it appeared that the SR22 was going to position behind the PA38; therefore the controller continued with other tasks. At 1739:55 both aircraft were depicted on radar replay, approximately 2nm east-northeast of Hawarden and 0.7nm apart (Figure 1).

Hawarden

Figure 1: Clee Hill/Great Dun Fell composite – 1739:55

SR22

PA38

4

At 1739:59 the PA38 pilot reported, “about to turn downwind we’re visual with the cirrus close behind us”. Tower replied “Roger,” and then transmitted: Tower: “(SR22 c/s) just confirm you’re visual with the PA38” Tower: “(SR22 c/s) Hawarden” Tower: “(SR22 c/s) Hawarden Tower radio check” SR22: “(SR22 c/s) say again it’s very bad to hear you” Tower: “Confirm you’re visual with the P A 38” Immediately after this the PA38 pilot reported, “he’s passed over us now.” This was acknowledged by Tower but no response was received from the SR22. Figures 2 and 3 bel ow depict the crossing of the PA38 and S R22’s tracks between 1740:25 and 1740:32. The crossing of tracks occurred approximately 2.5nm east of Hawarden between the altitudes of 1300ft and 1400ft2

.

Figure 2: 1740:25

Figure 3: 1740:32

Tower transferred the SR22 to Radar at 1740:37 and the PA38 continued in the circuit to land. The Airprox occurred when the SR22 flew through the PA38’s 12 o’clock from right to left approximately 300-400ft above the PA38. Each pilot had been provided with traffic information on the other by the Tower controller. Summary A PA38 pilot was flying training circuits to RW04RH, and had completed a touch-and-go, when an SR22 pilot requested a VFR departure with a r ight-hand turn out. The Tower controller cleared the SR22 for departure and gave the pilot traffic information on the position of the PA38. The SR22 pilot does not appear to have assimilated this information and reports that he was alerted to the PA38s presence by a TCAS Traffic Alert; he did not manage to see the PA38 throughout the occurrence.

2 Radar replay processing altitude with respect to prevailing Manchester QNH, 1009hPa.

SR22

PA38

SR22

PA38

5

The PA38 pilot had noted that the SR22 was considerably faster than his own aircraft and reports that he maintained visual contact it. When he realised that the SR22 was turning inside his circuit he instructed his student to level at 900ft agl and the SR22 passed within 0.2nm of his aircraft with around 340-440ft vertical separation.


Information available included reports from the pilots of both ac and the Tower controller, transcripts of the relevant RT frequencies and radar video recordings. GA pilot and other Board members noted first that the PA38 pilot had made particularly good use of his student and had displayed outstanding situational awareness in recognising, at an early stage, the potential for a conflict. In contrast, they also opined that the SR22 pilot seemed to have become fixated on the ‘Traffic System’ in his cockpit at the expense of his look-out. Moreover, the PA38 had been on the same frequency as the SR22, as it had passed the SR22’s holding point during the PA38’s touch-and-go immediately prior to the SR22 pilot being issued departure clearance; in the Board’s judgement all of this gave the SR22 pilot ample opportunity to acquire the PA38 visually, before commencing his own departure. Furthermore, the Board noted that the SR22 pilot had a responsibility to ensure that he could see the PA38 before commencing his take-off. The Board then considered the Tower controller’s actions and noted that he had passed traffic information on the PA38 to the SR22 pilot, on more than one occasion; however, for whatever reason, the SR22 pilot did not appear to have assimilated the information. Although there appeared to be difficulty in establishing clear, two-way communication between the controller and the SR22 pilot, it was noted that the Tower controller had been persistent in his efforts to ensure that the pilots had the traffic information that they needed. The Board went on to commend both the PA38 pilot and the Tower controller for their efforts to avoid the confliction. A ware that the CAA were conducting a review of Visual Circuit procedures and definitions, it was agreed that this Airprox would be presented to the relevant CAA General Aviation Working Group in order to help them publicise the importance of assimilating traffic information with visual cues and other sources of information in order to develop sound situational awareness. When discussing the cause, the Board agreed unanimously that, despite the availability of traffic information from Tower and his own ‘traffic system,’ the cause of the Airprox had been that the SR22 pilot had not seen the PA38, and had taken-off and flown into confliction with it. In determining the risk, the Board noted that the PA38 pilot had maintained visual contact with the SR22 throughout and, consequently, had been able to achieve the eventual separation of 0.2nm; it was also clear that, if necessary, he could have continued to take further avoiding action The Board therefore concluded that the Degree of Risk was C.


Cause: The SR22 pilot flew into conflict, in the visual circuit with the PA38, which he did not see. Degree of Risk

: C

ERC Score3

: 4


1

AIRPROX REPORT No 2013059 Date/Time: 26 Jun 2013 1238Z

Position: 5135N 00048W (Wycombe A/D - elevation 520ft)

Airspace: Wycombe ATZ (Class: G)


Type: ASK13 C182

Operator: Civ Club Civ Pte

Alt/FL: 1800ft 2120ft QFE (NK) QNH (1030hPa)

Weather: VMC NK VMC NK

Visibility: 20km 10km


50ft V/0m H 550ft V/0m H


NK


THE ASK13 PILOT reports conducting a student instructional sortie. They were operating under VFR in VMC, listening out on the ‘Booker Gliding Radio’ frequency. The blue and white ac was not fitted with lights, an SSR transponder or an ACAS. He took off from RW24 under aero-tow and, after releasing at height 2000ft to the W of the A/D, they preceded to make their way E, back towards the A/D. About 1nm to the S of the A/D, and now at height 1500ft, they entered a thermal and started turning to the L to gain height. They were subsequently joined by 3 other gliders below them. After a few minutes of circling they had gained height to 1800ft, with the three other gliders remaining in view, circling below them in the thermal. Whilst turning through an E’ly heading, he saw a brown coloured high wing light ac flying directly towards his glider. He had no time to take avoiding action and within 1-2sec it passed no more than 50ft below. He exited the thermal and called Wycombe TWR to report the Airprox and ask if they had the other ac on frequency. They indicated they were in RT contact with the light ac and had cleared the pilot to transit through the southern part of the ATZ, no lower than altitude 2100ft (about height 1580ft). He assessed the risk of collision as ‘High’. THE C182 PILOT reports transiting in level cruise, on the leg from Wycombe to Chilbolton. He was operating under VFR in VMC with a BS from Farnborough, he thought, and in contact with Wycombe TWR, who had advised him of gliders in the area. The strobes and ‘running lights’ were selected on, as was the SSR transponder with Modes A, C and S. The ac was not fitted with an ACAS. Heading 224° at 132kt and altitude 2120ft [QNH 1030hPa] with the A/P engaged, he saw 3 white gliders, 2 of which were 5-600ft below and the other 5-600ft above, which turned ‘across’ him from L to R. He did not perceive any danger of collision and remained on course. Factual Background The weather at London Heathrow was recorded as follows:

METAR EGLL 261220Z 34006KT 240V040 9999 FEW049 21/08 Q1030 NOSIG METAR EGLL 261250Z 30006KT 250V350 9999 FEW049 20/07 Q1030 NOSIG


C1822200ft alt

CPA 1238

Faded PSR group

NM

0

1

2

2


CAA ATSI The ASK13 pilot was in communication with Booker Gliding Radio on 129.975MHz. The C182 pilot was on a private VFR flight and was in communication with Wycombe TWR on 126.550MHz. Wycombe Air Park is a non-surveillance aerodrome unit providing Aerodrome Control Services. Wycombe is in Class G uncontrolled airspace and has an ATZ of radius 2nm centred at 513642N 0004830W and extending from the surface to 2000ft aal. The aerodrome elevation is 520ft. The UK AIP AD 2.EGTB, dated 4 Apr 2013, notifies pilots that:

‘2.20 Local Traffic Regulations 4 (c) Intense gliding takes place on and around the aerodrome. Pilots should maintain a sharp lookout at all times.

2.22 Flight Procedures

1 (b) Gliders will be flying a circuit opposite to that in use by powered aircraft. 3 (a) (iii) Pilots of aircraft flying within the confines of the Wycombe ATZ are responsible for providing their own separation from other aircraft operating within the ATZ.’

ATSI had access to both pilots’ reports, recorded area surveillance and transcription of the Wycombe TWR frequency. Additionally ATSI undertook a site visit to Wycombe.

The C182 pilot had been in receipt of a Basic Service from Farnborough LARS (N) and had been issued with QNH 1030hPa. As he approached Wycombe, on a W’ly track, the Farnborough controller instructed him to free-call Wycombe TWR for an ATZ transit; following which the pilot was instructed to call Farnborough LARS (W). The C182 pilot was instructed to squawk 7000. At 1230:30, an aircraft reported downwind to land on RW24 on the Wycombe TWR frequency. The pilot reported, “visual with the gliders”. The incumbent controller reported that he knew nothing about them. A hand-over of operational position then took place. Wycombe ATC had access to the Booker Gliding frequency; however it was not routinely monitored or utilised. Gliders operating in the ATZ were not required to monitor or utilise the Wycombe TWR frequency. Some gliders that may operate within the ATZ are not radio equipped. The C182 pilot called Wycombe TWR at 1233:50, and at 1234:20 he requested a zone transit, informing Wycombe TWR that he was at 2100ft on QNH 1030hPa. The C182 was 7.1nm E of Wycombe with a surveillance-recorded altitude of 2200ft. Wycombe TWR approved the zone transit on QNH 1031hPa, “not below an al titude of 2000ft.” After a correct read-back, Wycombe informed the C182 pilot, “we are gliding so ke- keep a good lookout for glider activity within the traffic zone.”. This was acknowledged. The Wycombe Manual of Air Traffic Services (MATS) Part 21

instructs controllers as follows:

‘Aircraft in transit through the ATZ are to be instructed to fly on the Aerodrome QNH.’

The Wycombe MATS Part 22

describes the allocation of ATZ airspace as follows:

‘The ATZ is divided into two basic sections to separate glider operations from powered (fixed wing and rotary) operations. …

1 Wycombe MATS, Chapter 1, Section 1, paragraph 2, dated 15 March 2007. 2 ibid., Chapter 2, Section 3, paragraph 2.

3

A Safety Buffer Zone has been established to provide separation between the Gliding Section and the Power Section airspace. The boundaries of the Safety Buffer Zone extend to the limits of the ATZ and are defined on the manoeuvring as follows: When R/W 06/24 is in use: The Power Section Boundary is defined as the southern edge of R/W 06/24 Grass. The Gliding Section Boundary is defined as a line positioned parallel to and 30m south of the Power Section Boundary. … In order to preserve the value of the Buffer Zone System for safety purposes both the Power and Gliding Sections must promulgate the same runway direction for use, although opposite handed circuits will be flown. Unless prior approval has been given, no Gliding Section traffic is permitted to enter the Power Section airspace at or below 1400’ QFE (1900’ QNH). Similarly, unless specifically authorised by ATC and Gliding Co-ordinator, no Power Section traffic is to enter the Gliding Section airspace at or below 1400’ (1900’ QNH’).’

The C182 entered the Wycombe ATZ at 1236:39 (see Figure 1 below).

Figure 1: Swanwick MRT – 1236:39

As the C182 pilot approached Wycombe he altered course to the SW (see Figure 2 below).

Figure 2: Swanwick MRT – 1237:39

The C182 pilot departed the Wycombe ATZ at 1238:15 at a converted Mode C altitude of 2200ft.

4

At 1238:30, the ASK13 pilot called Wycombe TWR and asked, “Did you have the er Cessna one seven two that’s just passed to the south of the airfield about 1800ft in our zone on frequency.” The controller replied, “Yeah his clearance is a transit not below two thousand feet on QNH.” The pilot then stated, “he was at 1800ft and he’s just gone through a thermal of about four gliders.” ATSI noted that both the glider pilot’s Airprox report and the ATC unit watch log record the ASK13’s level at the time of the Airprox as 1800ft on QFE. The Wycombe TWR asked the C182 pilot if the ASK13 pilot’s report had been copied. The C182 pilot replied, “Roger that my er altimeter says two thousand one hundred feet.” The C182 pilot departed the Wycombe frequency for Farnborough LARS (W) at 1242:30. Upon making contact with LARS the pilot requested verification of the aircraft’s Mode C. The Farnborough controller reported that radar displayed the aircraft’s altitude as 2200ft on 1030hPa and the pilot stated his altimeter read 2100ft on 1030hPa. Wycombe issued a Temporary ATC Operating Instructions (TOI 2/2013) on 4th September 2013, which stated as follows:

‘With immediate effect, when gliding is in progress, ATC must refuse all ATZ transit requests. Pilots must instead be instructed to remain outside the Wycombe ATZ.’

The UK AIP ENR 1.6, paragraph 2.1.4 (e), requests that pilots report their altitude to ATC to the nearest 100ft. ATC will inform pilots of discrepancies in excess of 200ft. Therefore the C182 pilot’s altitude was verified satisfactorily and ATSI consider that the aircraft transited the Wycombe ATZ at altitude 2100ft. The ASK13 pilot was not in contact with Wycombe TWR: indicated in the pilots report and by the need to request details of the C182, which had been given ATZ transit clearance on the TWR frequency. The ASK13 pilot reported the Airprox level as about 1800ft QFE, which is equivalent to altitude 2300ft; therefore he is considered to have been above the C182’s transit altitude. In accordance with Rule 45 of the Rules of the Air Regulations 2007 (as amended), aircraft shall not fly within [an] ATZ unless the commander has [obtained] the permission of the ATC unit to enable the flight to be conducted safely within the zone. Therefore, having obtained ATC’s permission, the C182 pilot acted in accordance with Rule 45. CAA Legal advised ATSI that the form of the Rule 45 permission is not specifically detailed within the legislation; therefore such a permission could be given as specific RTF transmission to an individual aircraft or as a blanket permission as appears to be the case for glider operations at Wycombe. Neither the ANSP nor gliding organisation could provide ATSI with any documentary evidence in support of such a permission for gliders to enter or operate within the ATZ. However, the unit considered that, as procedures for ATZ utilisation were contained within their MATS Part 2, the permission existed. No reciprocal evidence of this fact was produced by the gliding organisation. It was noted that the Wycombe ATZ utilisation procedures have been extant for in excess of 20 years. Aerodrome controllers will issue information and instructions to aircraft under their control to achieve a safe, orderly and expeditious flow of air traffic and to assist pilots in preventing collisions between aircraft flying in, and in the vicinity of, the ATZ3

. This aligns with Rule 45, against which ATC give permissions to enable safe conduct of flight.

The Wycombe controller gave a transit clearance of not below altitude 2000ft, which the unit informed ATSI was standard operating practice at Wycombe. Such a clearance provides segregation from any powered traffic operating under ATC instruction within the ATZ. However, since ATC are only aware that gliders are, or may be, present in the ATZ, transit clearances do

3 CAP493 Manual of Air Traffic Services, Part 1, Section 2, Chapter 1, paragraph 2.1, dated 4 April 2013.

5

not provide any assurance of segregation against gliding traffic. Hence, transit aircraft are warned of the presence of gliders. As the Wycombe ATZ is Class G airspace, the responsibility for collision avoidance rests solely with the pilots concerned. There appear to be several distinct disadvantages to the operation of the Wycombe ATZ: Any transit traffic in receipt of an ATC permission, which the pilot could reasonably assume provides for safe conduct of the flight, still relies on see-and-avoid. Pilots are warned in the AIP of Wycombe’s gliding operations; however, it could be considered unlikely that many pilots of transit aircraft are aware of this information in advance. The ability of glider pilots to see-and-avoid may not be assisted by their autonomous operation within the ATZ. Being within the ATZ could be interpreted by pilots as providing an element of protection against other traffic. Indeed, the ASK13 pilot stated, “in our ATZ”. Any agreement between ATC and gliders predicated upon non-radio operations is very likely to be centred on an assumption by the non-radio pilot that he is operating in a reasonably ‘controlled’ and therefore ‘safe’ environment. The lack of two-way communication between gliders and ATC, whilst understandable from an RTF utilisation point of view, could compound any assumption of protection. Any pilot in receipt of an ATZ permission from ATC, in whatever form it takes, might reasonably be expected to challenge, as a point of law, an unsafe situation within the ATZ, which appears to derive from conflicting utilisation of the ATZ airspace. An Airprox was reported within the Class G ATZ at Wycombe Air Park between an ASK13 and a C182. Surveillance evidence was unable to further determine the geometry of the encounter. The ASK13 pilot was operating in accordance with procedures for gliding operations in the ATZ and the C182 pilot was operating in accordance with an ATC permission. Wycombe ATC and the C182 and ASK13 pilots all acted in accordance with their own requirements and understanding; however, notwithstanding both pilots’ responsibility to avoid collision, the utilisation of Wycombe’s ATZ airspace does not support to the best possible extent the integration of transit aircraft when autonomous gliding operations are in progress. Further to the existing Wycombe TOI it was recommended that the Wycombe aerodrome ANSP, in conjunction with the CAA’s ATS (Southern) Regional Inspectorate and all other stakeholders utilising Wycombe ATZ, publish procedures, to be held by all stakeholders, that outline the operations of powered and gliding traffic in the ATZ; and which, in so far as is reasonably practicable in a Class G airspace environment, provide that permissions given by ATC can be discharged such that flights may be conducted safely with the zone.

Summary A C182 pilot and an ASK13 pilot, on different Wycombe/Booker RT frequencies, flew in to confliction at 1238 on 26th June 2013 in the Wycombe Air Park ATZ. The ASK13 pilot was operating from Wycombe and the C182 pilot had received permission to enter and transit through the ATZ.


Information available included reports from the pilots of both ac, a transcript of the Wycombe TWR frequency, radar video recordings and a report from the appropriate ATC authority. The Board first considered the history of operations at Booker/Wycombe Air Park. It was established that civilian gliding started at the then Booker airfield in 1957, with civilian powered aircraft moving to Booker in 1965, and the airfield setting up as Wycombe Air Park in 1966. An ATSU was established in 1991. A civilian ATC member stated that the Wycombe ATZ was effectively spilt into 3 parts: either

6

side of the main runway up to altitude 1900ft (1400ft aal); and above altitude 1900ft. Powered and gliding activity occupied the lower split on their exclusive sides, and the airspace above was available to all traffic. Transiting traffic was routinely passed a warning of other traffic in the ATZ. The Board went on to consider the actions of the pilots. Both were operating under VFR in VMC in Class G airspace and were equally responsible for collision avoidance4; the C182 pilot was required to give way to the glider5. The C182 pilot had been cleared to transit the ATZ and did so at an altitude of about 2100ft (1600ft aal). The ASK13 pilot reported his height as 1800ft aal, an altitude of 2300ft, and he was consequently in a position above the notified ‘Glider Section’ of the Wycombe ATZ structure, operating in the shared part of the airspace. The Board opined that this fact may not have been apparent to him at the time, and that this may in turn have led to a misapprehension as to the expected level of deconfliction. Members discussed potential changes to the Wycombe ATZ regulations at length and, notwithstanding the requirement for glider pilots to receive explicit permission to fly within the ATZ6, also noted that the arrangements for shared ATZ usage had been in operation for in excess of 20yrs without serious incident7

.

Board members noted that there was a marked difference between the reported vertical separations during the incident. They also noted that the C182 pilot reported 3 gliders, 2 below him and 1 above, whereas the ASK13 pilot reported being the highest in a thermal of 4 gliders. Members were not able to resolve this geometry or the reported vertical separations and opined that the C182 pilot may not have seen the ASK13. In any case, the ASK13 pilot reported that he had sighted the C182 so late that he had insufficient time to take avoiding action and therefore that his had been an effective non-sighting. Given the reported data, it was concluded that safety margins had been much reduced below the normal.


Cause

: A possible non-sighting by the C182 pilot and an effective non-sighting by the ASK13 pilot.

Degree of Risk

: B.

ERC Score8

: 20.

Recommendation(s)

:

1. BGA Instructors’ Panel reviews gliding activity at Booker.

2. Wycombe reviews procedures for powered and glider traffic integration in the ATZ.

3. The CAA reviews the education of GA pilots regarding overall awareness of gliding operations with specific emphasis on flight in the vicinity of glider sites.

4 Rules of the Air 2007 (as amended), Rule 8 (Avoiding aerial collisions). 5 ibid., Rule 9 (Converging). 6 ibid., Rule 45 (Flights within aerodrome traffic zones). 7 A search of the UK Airprox Board database resulted in 3 Airprox reports in the last 10yrs and 7 in the last 20yrs. Of these 7 reports, 3 were risk bearing ,1 of which involved a Booker based glider (on 26th June 1995). This event occurred outside the hours of operation of the Wycombe ATSU at the time. 8 Although the Event Risk Classification (ERC) trial had been formally terminated for future development at the time of the Board, for data continuity and consistency purposes, Director UKAB and the UKAB Secretariat provided a shadow assessment of ERC.

1

AIRPROX REPORT No 2013061 Date/Time: 1 Jul 2013 1458Z

Position: 5627N 00302W (2nm E Dundee Airport- elevation 17ft)

Airspace: Dundee ATZ (Class: G)


Type: Do328 PA34

Operator: CAT Civ Trg

Alt/FL: 2000ft 1000ft QNH (1010hPa) QNH (1010hPa)

Weather: VMC VMC CLBC

Visibility: >10km 30km


50ft V/100m H NK


NK

PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE Do328 (Dornier 328-100) PILOT reports inbound to Dundee on an IFR flight from Aberdeen, in receipt of a Procedural Service from Dundee TWR/APP. The crew had selected the white and strobe lights, together with navigation, beacon and landing lights. The aircraft was squawking 7000, Modes S and C. Approaching Dundee from the N on a visual right-base for RW27 he was informed he was number two and shortly becoming number one1. While turning onto final for RW27 a TCAS TA was received, followed very shortly by an RA to climb. The traffic, which he first observed at a distance of 0.5nm, was a light twin turning from left-base onto RW27 simultaneously with him at the same level. It then passed below his aircraft. An RA climb was commenced by the First Officer (FO), the handling pilot, towards the Dundee overhead (O/H). The light twin was on the left-hand side and with visual contact of the aircraft the aircraft Captain took control to climb further. (The FO was not visual with the aircraft at the time.) Subsequently, the FO again took control, climbing to 2000ft towards the O/H. A left-hand visual circuit to RW27 was carried out without any further incident. He assessed the risk of collision as ‘High’. THE PA34 PILOT reports on a VFR training flight inbound to Dundee from Perth, under the control of Dundee TWR. His aircraft is coloured white and blue, SSR Mode C was selected, Mode S is not carried. (No report of the external lights was made.) He was left-hand downwind in the circuit to RW27 at Dundee at 1000ft agl, tracking 090°(M), when he heard a garbled message from what he, subsequently, realised was an incoming aircraft. ATC responded and he heard the words ‘South Bank’. He assumed that the aircraft was approaching from his right and probably positioning onto left-base. He continued at the correct parallel displacement from the RW, downwind at 1000ft. He could not see any aircraft either above or below on the right or left, or on base leg, or on final, or positioning from the Visual Reporting Point at Broughty Castle. He extended slightly further downwind to a position halfway between the Rail Bridge and the Road Bridge on the S river bank, whilst continuing to look for traffic. He commented that he did not want to turn onto left-base any earlier because he did not want to obscure his view of an aircraft approaching from the right. He had heard no transmissions

1 The Dundee RT transcript confirmed that the Do328 pilot was informed he was number two in traffic but not that he was

shortly becoming number one.


D328

CPA 1500

1500:12 A12

1500:52 A20

00:00 A13

59:48 A17

59:36 A19

59:24 A22

RAF Leuchars MATZ

PA341000ft alt

2

from the incoming aircraft clearly stating its position. He asked Tower if it was clear to turn onto left-base and this was approved. As he made the turn onto left-base, he had the first sighting of the inbound aircraft, which was O/H the airport at about 1000ft above and approximately 2nm distance. With the aircraft O/H the airport he continued a turn onto base-leg and then started to descend from 1000ft, before making a turn onto final. He said that at no time before the first sighting of the aircraft had he intercepted or crossed the inbound centreline of RW27. He finished his report by saying that he was not entirely clear that his aircraft was the one involved in the Airprox. THE DUNDEE TWR/APP CONTROLLER reports that during a relatively busy traffic pattern the Do328 was on a visual approach to Dundee and the PA34 was in the visual circuit left-hand for RW27. When the Do328 reported on frequency it was instructed to continue for a visual approach to RW27, number two in traffic. The PA34 reported downwind to land and was instructed to continue. He was expecting the Do328 to arrive from the SE for a left-base. At his request the Do328 reported approaching the City and the Road Bridge. However, he was not able to see it. The pilot of the PA34, who had not turned onto left-base as expected, remaining on the downwind leg, was asked if he had the Do328 in sight. Replying negative he was advised to continue the approach but to maintain 1000ft, the circuit height. He then asked the Do328 pilot if he had crossed the river. As the pilot responded, reporting a TCAS RA (against the PA34 on base-leg), he observed the Do328 N of final approach. The PA34 was instructed to continue approach and landed without further incident. The Do328 maintained 2000ft to the O/H, then flew a visual left-hand circuit to land. Factual background The Dundee weather was:

METAR EGPN 011450Z 25013KT 9999 FEW010 SCT045 16/07 Q1011= METAR EGPN 011420Z 25011KT 9999 FEW010 SCT045 16/07 Q1010=

Dundee ATZ is a circle, 2nm radius centred on RW09/27, from surface to 2000ft. Dundee ATC is not radar equipped.

MATS Part 1 states ‘Aerodrome Control is responsible for issuing information and instructions to aircraft under its control to achieve a safe, orderly and expeditious flow of air traffic and to assist pilots in preventing collisions between: 1) Aircraft flying in, and in the vicinity of, the ATZ’.2

MATS Part 1 states ‘Separation standards are not prescribed for application by ATC between VFR and IFR flights in Class D airspace’3. The CAA published a Safety Notice 4 titled ‘Integrating Traffic in the Vicinity of an Aerodrome’ which states:

‘...The incident data highlights the importance for controllers to have established a plan for the safe integration of aircraft before they converge towards final approach, as well as the challenge that a controller is presented with when aircraft are established on directionally opposed base legs and/or when integration is required with an aircraft on an instrument approach. In such circumstances, early integration actions are required as delaying such manoeuvres results in very limited options and significantly increased risk. Controllers should therefore take these factors into account when establishing a plan and communicating an order in which aircraft are to approach an aerodrome for a landing, also bearing in mind that VFR aircraft may be unable to visually acquire IFR aircraft, e.g. when the IFR aircraft has not yet descended below cloud or is hidden by aircraft structure or glare...’

2 MATS Part 1, Section 2, Chapter 1, Paragraph 1.4. 3 MATS Part 1, Section 1, Chapter 5, Paragraph 5.3. 4 CAA Safety Notice 2013/001

3


CAA ATSI

CAA ATSI had access to written reports from both pilots, the Dundee Tower controller, area radar recordings, radar recordings from Edinburgh Airport, RT recordings and transcripts of the Dundee Tower frequency, together with the unit investigation report. ATSI also interviewed the Dundee Tower controller. The Dundee Tower controller (ATCO(1)) was providing an Aerodrome Control Service without the aid of surveillance equipment or Direction Finding equipment. At interview, he commented that he was significantly distracted prior to presenting himself for duty and this was compounded by the administrative tasks that he felt compelled to complete. Another controller, who was not operational at the time, was present in the Tower (ATCO(2)). At 1454 RAF Leuchars telephoned Dundee to notify ATC of the inbound Do328. ATCO(1) was busy dealing with an aircraft that had stopped in the wrong place on the apron and in a bid to help his colleague, ATCO(2) took the call. Leuchars advised ATCO(2) that the Do328 was approaching from the N. The callsign of the Do328 indicated to ATCO(1) that it was operating a charter service. Most charter operations into Dundee operate from the S. ATCO(2) asked ATCO(1) if he wanted the Do328 to route to the O/H at 3000ft but, due to pending departure traffic that would be delayed if the Do328 routed to the O/H, ATCO(1) informed ATCO(2) that he wanted the Do328 to route towards a visual left-base for RW27. As there is no RT loudspeaker in the tower at Dundee, ATCO(2) was unaware of the operational situation at the time. The routeing towards left-base could have been made for valid operational reasons and ATCO(2) did not question it. The instruction was passed on to Leuchars. When the Leuchars controller issued the left-base routeing to the Do328 the Leuchars controller realised that, as the aircraft was operating from the N, it would be more expeditious to join on right-base and changed the instruction to the Do328 accordingly. Leuchars did not inform Dundee of the amended routeing. The Letter of Agreement (LOA) between Leuchars and Dundee states: 'Nothing in this Letter of Agreement shall prevent any controller at RAF Leuchars or Dundee from using discretion to modify these procedures to achieve greater flexibility and efficiency for a specific aircraft movement, provided the other agency in this agreement is notified, agreement obtained, and flight safety not jeopardized.’ At 1458:15 the Do328 contacted Dundee Tower and reported being “on a right-hand visual er base for two seven”. The Do328 was instructed to continue approach and informed that it was number two in traffic. At 1458:40 the PA34, which was in the left-hand circuit, informed ATCO(1) that it was downwind for a touch-and-go RW27. ATCO(1) replied “roger continue”. ATCO(1) reported at interview that he was looking for the Do328 on left-base and could not see the traffic. At 1458:50 ATCO(1) asked the Do328 to report its position. The Do328 pilot reported that he was “coming up to the er the town on the road bridge”. At that point the Do328 was 5nm NE of Dundee tracking S. At 1459:30 the PA34 pilot reported ready to turn base and ATCO(1) asked if he was visual with the Do328 that was “east of the field now”. The PA34 pilot replied negative and ATCO(1) instructed him to turn base but maintain 1000ft. At 1500:00 ATCO(1) transmitted to the Do328 “I don’t see you from the control tower just confirm have you crossed the south bank of the river.” The Do328 replied “we’re just crossing the river now

4

turning onto base climb climb” before informing ATCO(1) that they had a TCAS climb. When the transmission saying “climb climb” was made the Do328 was 3.2nm ENE of the airfield on a base leg at FL011 (altitude 1046ft). At 1500:19 the Do328 was no longer visible on the radar recordings. The PA34 was not visible on the radar recordings at any time during the course of the incident. ATCO(1) reported that he obtained visual contact with the Do328 as it reported the TCAS RA. The unit investigation into the incident recommended that consideration is given to allocating a level to inbound aircraft that would vertically separate it from traffic in the circuit until the Dundee Tower controller obtains visual contact This would create a more effective means of complying with the recommendations produced in Safety Notice 2013/001. Military ATM All heights/altitudes quoted are based upon SSR Mode C from the radar replay unless otherwise stated. Although RAF Leuchars ATC were aware of the Airprox within the Dundee visual circuit, they did not perceive a requirement to submit occurrence reports for the incident. Consequently, when their contributory participation in the incident sequence became clear 3½ months later, the persons involved did not have a detailed recollection of events. However, RT and landline data from RAF Leuchars ATC, including ‘live-mic’ recording, were available to assist the investigation. From RAF Leuchars ATC’s perspective, the incident sequence commenced at 1454:14 as Leuchars Approach contacted Dundee ATC to pre-note the inbound Do328. During this landline exchange, at 1454:33, Dundee ATC advised Leuchars Approach “okay, [Do328 c/s] visual left base 2-7, Q-N-H is 10…[pause] I am not the controller on duty, 1-0-1-1.” Leuchars Approach read back this clearance and Dundee ATC then corrected themselves saying “disregard, it’s 1-0-1-0, I’m sorry” which was acknowledged. The Do328 was being provided with a Deconfliction Service (DS) by Leuchars Zone, which was operating in a ‘band-boxed’ Departures/Zone control position, a standard configuration for Leuchars ATC. Based solely on analysis of the RT transcript for the period of the incident, Leuchars Zone was subject to a relatively high task-load, providing ATS to a number of formations of departing Typhoons, in addition to Zone traffic. Although there is no evidence on the landline transcript of liaison between Leuchars Approach and Leuchars Zone, at 1456:20, Leuchars Zone advised the Do328, “own navigation for left base, runway 27” which was acknowledged. A second voice is then heard on the ‘live-mic’, during the Do328’s read back, saying “right base…that’ll be right base.” Leuchars Zone immediately advised the Do328 “[Do328 c/s] my apologies, own navigation for right base runway 2-7 at Dundee” which was acknowledged. The Do328 subsequently left Leuchars Zone’s frequency at 1457:54, 8.3 nm N of Dundee airport. RAF Leuchars ATC have assessed that this second voice was Leuchars Approach, talking to the Leuchars Zone controller. Although Leuchars Approach could not recall the incident when subsequently asked, it was considered likely that as the Do328 was approaching Dundee from the N, they had believed at the time that an error was made in instructing a left-base join and thus they prompted Leuchars Zone to instruct the aircraft to join via right-base. However, this amended routeing was not advised by Leuchars ATC to Dundee ATC, which is a requirement of the LOA between the 2 units. Given the lack of detail in the recollection of the incident by Leuchars ATC, it is not possible to determine why Dundee ATC was not notified of the amended routeing of the Do328. Leuchars Zone may have intended to notify Dundee ATC but forgot to carry out the action due to the distraction caused by other tasks, given their high task-load at the time. Allied with this, Leuchars Approach may have assumed that Leuchars Zone would have conducted this liaison. However, following this incident, SATCO RAF Leuchars reminded ATC personnel of the requirement

5

contained within the LOA to notify and agree with Dundee ATC any changes to the flight profiles of inbound aircraft.

Summary The Airprox occurred within Class G airspace near the boundary of the Dundee ATZ. Both aircraft were under the control of the Dundee controller, who was providing a combined Aerodrome/Approach service. The PA34 was inbound VFR, positioning downwind left-hand to RW27. The Do328 was inbound IFR from the N. However, ATCO(1) believed that the aircraft was inbound from the S. Consequently, when his colleague, ATCO(2), was discussing the aircraft’s arrival routeing with RAF Leuchars, he requested it to join on left-base. Although this was agreed, Leuchars changed the route to join on right-base, without informing Dundee, thereby not complying with the LOA. When the Do328 contacted Dundee, ATCO(1) did not register that the aircraft reported on right-base. The Do328 pilot was informed he was number two in traffic but no information was passed about the position of number one. The PA34 was not informed about the believed position of the Do328. ATCO(1) tried to obtain visual contact with the Do328 but this was not achieved because he was looking towards the SE, whilst the aircraft was approaching from the NE. The Do328, subsequently, reacted to a TCAS RA climb. The PA34 pilot did not observe the Do328 until after the Airprox. PART B: SUMMARY OF THE BOARD’S DISCUSSIONS Information available included reports from the pilots of both aircraft, transcripts of the relevant RT frequencies, radar video recordings, reports from the controllers involved and reports from the appropriate ATC and operating authorities. The Board first considered the actions of the Dundee Tower controller. The Board opined that the Airprox sequence started when the Dundee Tower controller made an incorrect assumption, based on its callsign, that the Do328 was approaching from the South as opposed to it in fact being inbound from the North. A civil ATC member commented that if the controller had looked at its flight progress strip it would have shown the departure airport (Aberdeen) and this would have quickly resolved the impending confusion. Acting on his incorrect assumption, the controller asked a colleague to co-ordinate the aircraft’s arrival with RAF Leuchars to join on left-base. This was agreed but, subsequently, seeing the direction of arrival, Leuchars amended the join, under their own initiative, to proceed onto right-base, without informing Dundee of the change. The Military ATM advisor confirmed that this change should have been notified to Dundee. Board members considered this to be a contributory factor to the Airprox. Nevertheless, on initial contact the Do328 reported right-base and the Board opined that the controller should then have assimilated this information and re-appraised his understanding of the dynamics of the situation. Several members queried the performance of the Dundee controller. The ATSI advisor reported that during their investigation the controller had reported being distracted prior to presenting himself for duty and had also reported that he had been expected to carry out administrative tasks whilst at work, and that this had distracted him further. The Board considered this to be a contributory factor to the Airprox. The Do328 pilot was advised that he was number two in traffic but not, as he thought, shortly becoming number one. ATC and pilot members all agreed that the controller should have stated the position of the number one to the Do328 pilot in order to assist him in sequencing his join. Equally, because he had omitted this information, the Do328 pilot should have queried it. This was important because the Do328 would require visual contact with number one in order to join the circuit safely. Both of these omissions in action were considered to be contributory to the Airprox. When the PA34 pilot reported downwind, he was instructed to continue but not advised of his sequence number in the traffic pattern. At this point the controller was still looking for the Do328 approaching from the South. The Do328 pilot reported his position as “coming up to the town on the road bridge” but Board members considered this an ambiguous call because built-up areas are situated at both the north and south ends of the road bridge. They considered there should have been more positive position reports used by both ATC and the pilots; this was considered to be another contributory factor. When the PA34 pilot reported ready for base-leg neither he nor the

6

controller had visual contact with the Do328. He was instructed to turn base but to maintain 1000ft. This was a precaution so that the PA34 could be broken off the approach at a safe altitude if the Do328 was seen to be too close, but the Board considered that this may have introduced a further element of doubt as to which aircraft actually was number one in the traffic pattern. Ultimately, the Do328 continued towards final approach with no visual contact with the PA34 and then turned into conflict with the aircraft. This was considered by the Board to have been the cause of the Airprox. Subsequently, the Do328 pilot reported reacting to a TCAS RA climb and then the Captain took control of the aircraft because he had the PA34 in sight. Civil airline pilot members queried whether the Do328 crew had fully followed the TCAS RA, as the system would normally provide more than the reported 50ft vertical separation. They also queried the Captain’s rationale for taking control. Assuming that the handling pilot had applied the required control inputs on receipt of the TCAS RA, his actions should have generated sufficient separation. Although the separation as reported by the Do328 pilot had been 50ft vertical and 100m horizontal, the Board considered that, in these circumstances, there was in fact no risk of a collision because the Do328 pilot had received and actioned a TCAS RA and was then in visual contact with the PA34 as they climbed. Consequently, the risk was classified as Category C. PART C: ASSESSMENT OF CAUSE AND RISK Cause: Having been told that he was No.2 in the pattern, but in the absence of effective

Traffic Information, the Do328 pilot turned into conflict with the PA34. Risk: C. Contributory Factors: 1. Leuchars did not coordinate the right-hand base join with Dundee. 2. There was insufficient Traffic Information from ATC regarding the PA34. 3. The Dundee Controller was distracted by non-operational tasks. 4. The use of ambiguous reporting points. 5. A lack of questioning of the Traffic Information by the Do328 pilot. ERC Score5: 10.


1

AIRPROX REPORT No 2013070 Date/Time: 9 Jul 2013 1845Z Position: 5501N 00128W (8nm ESE NATEB)

Airspace: UAR UL602 (Class: C)

Reporter: PC Montrose Sector

1st Ac 2nd Ac

Type: B777 Typhoon FGR4

Operator: CAT HQ Air (Ops)

Alt/FL: FL380 FL330 Weather: VMC NK VMC CLAC

Visibility: N/R 10km

Reported Separation

Not seen 5000ft V/NK H


5000ft V/0.2nm H

CONTROLLER REPORTED PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE MONTROSE CONTROLLER reports working as Tactical (T) and Planner (P) on the band-boxed Montrose/Tyne/Humber Sectors. He was in the middle of a handover when he spotted two squawks (5111/5112) N of NATEB by 5nm at FL220, which were climbing and heading SE towards the B777. He had previously given the B777 a descent, when ready, to FL260 but as the military continued climbing and tracking head-on he cancelled the descent. The pilot advised he had already started descent but then advised he was maintaining FL380. The other controller took over as the P controller and telephoned the military to co-ordinate the traffic. As he was unsure if separation could be ensured he issued an avoiding turn to the right and then observed one of the military aircraft at FL330 and the other with no Mode C. THE RELIEF MONTROSE CONTROLLER reports arriving at the Montrose sector to take over the band-boxed Montrose/Tyne/Humber Sectors as the T and P controller. During the handover both controllers observed a 5111 and 5112 squawk NW of NATEB climbing rapidly through FL230. The off-going controller had already cleared the B777 (maintaining FL380) to FL260. As the two military squawks passed FL260 he unplugged from the T controller side, plugged in on the P controller side and telephoned Boulmer MIL to request immediate co-ordination. The T controller wanted to give avoiding action but he advised him to keep the B777 on-route until the intentions of Boulmer MIL were known. He received traffic information (TI) that the squawks were climbing to maintain FL330 (he believed they were indicating RVN on radar). He observed the 5112 squawk passing FL340 before its SSR label disappeared. By this stage right-turn avoiding action had been given by the T controller and the B777 had been instructed to maintain FL380. He passed this information to Boulmer MIL and asked their intentions. On stating that they were turning to the E, the B777 was turned back towards the ScTMA. He decided to file the incident as an Airprox. THE BOULMER WEAPONS CONTROLLER (WC1) reports he was controlling 2 Typhoons in Operational Training Area (OTA) E which called for return to base (RTB) at approx 18:44Z. The aircrew requested a climb to FL350 and a direct track to Coningsby. This was approved and the aircraft began to climb. The Allocator pointed out traffic in the Vale of York at FL380 that was going to

2

be a factor and so he decided to stop the climb of the Typhoons at FL330. This was agreed by the aircrew. He discussed with the SUP which sector would be controlling the traffic at FL380 and he subsequently attempted to telephone the Montrose sector, at approx 18:45Z, when the civil aircraft was approximately 45nm from the Typhoons. There was no response from the sector. However, the Typhoons were levelling at FL330 and the civil traffic was maintaining FL380 with no Mode S indications of a decent. At approx 18:46Z the Allocator transferred a call to him from the Montrose sector. The Montrose controller asked for TI about the Typhoons, which were now about 25nm from the civil aircraft. He subsequently asked him to avoid his traffic that was going to descend en-route. Accordingly, he issued a Radar Control turn to the Typhoons onto E in order to remain clear. Co-ordination was agreed with Montrose for the Typhoons to maintain FL330 and the civil traffic would not descend below FL350. THE B777 PILOT reports inbound IFR to Glasgow Airport, squawking SSR code 3436, under control of Scottish Radar. Strobes and navigation lights were illuminated and SSR Modes S and C were selected. The flight-deck crew complement was three pilots. He was heading 310°, 498kt at FL350 (he thought) when radar instructed a right turn heading 100° (he thought). He was informed about a formation head-on at FL330. He did not see the traffic or receive a TCAS target on the display. THE TYPHOON PILOTS report that all external lights and white HISLs were illuminated, the two aircraft were squawking Modes S and C, codes 5111/5112 respectively. They had completed a tactical training sortie in OTA E, during which time Hotspur (HR) had been providing a Traffic Service (TS). On completion, a recovery was initiated to RAF Coningsby, with Typhoon(1) initially heading 140°M and requesting a climb to FL350 at 1843:58. HR approved this request and a subsequent request, at 1844:28, for a right turn onto 155°M. Typhoon(2) was, initially, in approximately 2nm trail on Typhoon(1) but closed on it during the climb in order to achieve standard formation (inside 1nm). Due to being initially outside standard formation limits, Typhoon(2) continued to squawk M3/A+C during the climb. At 1844:48 HR instructed the Typhoon formation to stop climb at FL330, due to traffic at FL380. Typhoon(1) immediately gained radar contact on this traffic, 50.9nm away. At 1847:07 HR instructed Typhoon(1) to turn left onto 090°M. The Typhoon formation levelled at FL330 coincident with this transmission, with Typhoon (2) briefly ballooning to 33,250ft with 1013hPa set at 1847:12, before immediately correcting to FL330. At this time the civilian traffic was 16.2nm from Typhoon(1). During the level off Typhoon(2) closed inside standard formation parameters on Typhoon(1), deselecting M3/A+C and called “aboard” to Typhoon(1). Typhoon(1) then informed HR that the Typhoon flight were “standard formation” at 1847:18. HR then requested Typhoon(2) to descend to FL330 at 1847:25. Typhoon(1) replied that the Typhoon formation was in standard formation, level at FL330. At 1847:56 Typhoon(1) called steady 090°, level FL330, with no response from HR. At 1848:12 Typhoon(1), concerned at the lack of response from HR, requested a radio check. HR responded with an update on the civilian traffic. Typhoon(1) informed HR that the Typhoon formation was visual with the traffic (which had been tracked on radar throughout) and that the Typhoon formation was level at FL330. At this time the Typhoons were in the vicinity of the Newcastle airport overhead. At 1848:53 the Typhoon formation was cleared to route direct to RAF Coningsby, after requesting a right turn onto 155°M. This report was completed after reviewing the cockpit video recordings of both Typhoons. The Typhoon pilots assessed the risk of collision as low. Factual Background The MATS Part 11 describes formations: ‘Formations are to be considered as a single unit for separation/deconfliction purposes provided that the formation remains within the parameters shown’. For Class C airspace these are 1nm laterally and longitudinally and at the same level. The MATS Part 12 states that under a Radar Control Service: ‘If the intentions of Mode C transponding aircraft are not known, the minimum separation must be increased to 5000 feet. 1 MATS Part 1, Section 1, Chapter 4, Page 8

2 MATS Part 1, Section 1, Page 15

3

Unverified Mode C data may be used for separation purposes provided a minimum vertical separation of 5000 feet is maintained and radar returns, however presented, are not allowed to merge’. The MATS Part 13 defines On-Route (ATS): ’This term is used routinely by ATC for co-ordination purposes within the UK; aircraft are considered to be ‘on-route (ATS)’ when flying along the alignment and within 5 NM of the centre-line of published parameters of an Upper ATS Route (UAR) and other areas defined for the application of reduced co-ordination procedures’.


CAA ATSI

CAA ATSI reports that it had access to written reports from both pilots, the Montrose T an P controllers, area radar recordings, RTF recordings and transcripts of the Montrose Sector frequency, together with the unit investigation report.

At 1844:31 the B777 was 37.4nm SE of NATEB at FL380 (Figure 1). The Montrose controller instructed the B777 to descend when ready FL260.

Figure 1

At 1845:58 the Montrose controller, having observed the 5111 and 5112 squawks climbing, cancelled the B777’s descent (Figure 2), and instructed the crew to maintain FL380 (the Montrose controller was planning for 5000ft separation against the Typhoons). The B777 replied that they had just started descent. The Montrose controller instructed the B777 to maintain FL360 due to unidentified military traffic whereupon the B777 replied that they were maintaining FL380.

3 MATS Part 1, Glossary, Page 10

4

Figure 2.

At 1846:10 the P controller initiated a telephone call to RAF Boulmer for ‘immediate coordination please 5111 5112 squawks radar controller please’. The P controller was instructed to ‘standby for controller’. The Montrose T controller instructed the B777 to turn right 15° however, the P controller instructed the T controller to leave the B777 on route (General Air Traffic (GAT) on-route has priority over Operational or Defence Air Traffic and military controllers are required to avoid the GAT and co-ordinate conflicting traffic).

At 1846:50 RAF Boulmer spoke to the P controller who requested information on 5111 and 5112 squawks before instructing Boulmer that they needed to avoid their 3436 squawk immediately as they were descending FL260 on route.

At 1847:00, as the 5111 squawk was climbing through FL325, the T controller issued avoiding action to the B777, instructing the crew to turn right immediately heading 060° (Figure 3).

Figure 3.

5

The P controller advised the Boulmer controller that the B777 was turning right to avoid their traffic to which Boulmer replied that the 2 Typhoons were turning E (due to conflicting traffic to the W) and would stop the climb at FL330. The Planner controller replied that the 5112 squawk was indicating FL340 on his screen (although this is likely due to the predictive element of Multi Radar Tracking (MRT) and the high climb rate of the 5112 squawk (calculated to be in excess of 8,000fpm)). Assessment of the Mode C readout from individual radars indicated that the 5112 squawk did not climb above FL323 before the Mode C was switched-off as the Typhoon joined formation with the lead aircraft.

The Planner and Boulmer controllers established between them that the 2 Typhoons were stopping the climb at FL330 and the B777 was instructed to resume own navigation. The Planner controller queried why Boulmer were climbing traffic against the B777 descending into the Scottish TMA and Boulmer replied that they did not know the B777 was descending and had climbed to FL330. Boulmer military controllers are permitted to operate autonomously inside certain areas of controlled airspace providing that they either co-ordinate against civil aircraft or apply 5nm or 5000ft separation.

At the closest point of approach (CPA) the B777 and the two Typhoons were 0.2nm and 5000ft apart where 5nm or 2000ft was required (as the Typhoons had been co-ordinated). Separation was not lost.

Military ATM

The Typhoon Formation was climbing to FL330 en-route to RAF Coningsby, in receipt of a Radar Control Service (RCS) from WC1 at Hotspur CRC, RAF Boulmer. WC1 was a relatively inexperienced controller and assessed workload as ‘high to medium’ with moderate task complexity. The incident sequence commenced at 1844:04 as the Typhoon’s advised WC1 that they were

“complete, looking for climb FL3-5-0”. In reply, WC1 instructed them “clear join and climb FL350…Radar Control above FL195.” At this point, the B777 was 63.1nm SE of the Typhoons, tracking NW’ly, at FL380 with a Mode S Selected Flight Level (SFL) of FL380; the Typhoons were tracking SE’ly in 1.6nm trail, indicating a climb through FL106 and FL95 respectively.

At 1844:30, the FA contacted WC1 and asked them “seen the 3-4-3-6 [the B777] yeah? Coming in at 3-8-0?” WC1 replied, “3-4-3-6? Yeah. I’ll stop them [the Typhoon Formation] at 33, think they are going direct CGY anyway.” The FA seemed to agree with WC1’s plan, replying “yeah makes sense.” WC1 then advised the Typhoon Formation “civilian traffic tracking north up the coast, stop climb FL 3-3-0” which was acknowledged. At this point, 1844:42, the B777 was 56.6 nm SE of the Typhoon Formation, tracking NW’ly at FL380; the Typhoon Formation was tracking SE’ly in 1.8nm trail, indicating climbing through FL135 and FL108 respectively. At 1844:43, the B777’s Mode S SFL changed to FL260. The Hotspur CRC incident investigation determined that neither WC1, the FA, nor the Master Controller (MC) identified that the B777’s Mode S SFL had changed and that all believed that the B777 was an over-flight of the UK. The ASACS UKASACS Command and Control System (UCCS) displays both Plot and Track information for aircraft that it detects. A Plot is the digital representation of the analogue radar response from primary and secondary sensors and can be displayed as a primary, secondary or a combined Plot. A Track is generated by the UCCS, based on the information fed into it from a combination of radars which need to be manually set by the operator. The Track is displayed ‘on top of’ the appropriate Plot. Track information is displayed in summary form next to a Track identifier. Generally a WC will display only the Track identifier and the aircraft callsign with the remainder of the Track information contained in the Track Tote in the Command and Control Display (CCD), located in the top right of the surveillance display. The Track Tote contains a large amount of information, including the aircraft flight plan, current SSR Mode C and Mode S SFL.

6

The radar Plot of the B777 had 2 Tracks associated with it. On reviewing the CRC’s surveillance data for the incident, tracking responsibility for the B777 transferred to Hotspur CRC at 1820:26 as the aircraft entered the London Upper Information Region (UIR). At 1821:27 UCSS generated a 2nd ‘pending’ Track for the B777, 1nm NE of the original Track. At 1822:07, this 2nd ‘pending’ Track ‘moved’ to become super-imposed on the original Track but no significant information was displayed in this 2nd Track; this Track picture was maintained throughout the incident sequence. The ‘pending’ Track is displayed as orange on a dark grey background, whilst an ‘active’ Track is displayed as green on grey; controllers may then ‘toggle’ between the Tracks. The CRC’s investigator determined that the colour scheme for ‘active’ Track symbology is distinguishable from the ‘pending’ Track symbology and has confirmed that Track information is visible on the ‘lower’ Track, through the ‘upper’ Track. The CRC investigator stated that this ‘pending’ Track should have been manually deleted by the CRC’s Surveillance team but was not. Dual Tracking is a known issue that occurs when the UCCS determines that there are 2 Plots in the same location, usually as a result of using surveillance sensors with over-lapping coverage where one of the contributing radars is not ‘registered’ correctly. In this instance, one of the sensors initially reported a Plot for the B777 in a slightly different location to the existing Plot and a separate Track was generated, appearing adjacent to the existing Track. Between 1843:28 and 1844:39, the B777’s Mode S SFL of FL380 ‘dropped out’ and ‘re-appeared’ on the Track on 4 occasions. UCCS detected and displayed the B777’s Mode S SFL change to FL260 at 1844:43 but ‘dropped out’ at 1844:47. Between 1844:53 and 1846:50, the B777’s Mode S SFL of FL260 ‘dropped out’ and ‘re-appeared’ on the Track on a further 8 occasions. It is believed that these problems were associated with the UCCS’ dual tracking of the B777. The CRC investigation assessed that ‘co-ordinating a recovery of climbing aircraft is one of the busiest times in a WC’s routine and [they] would not necessarily have the spare capacity to ensure that [they] had the correct track selected and would not be looking at [the Track Tote] overlooking at the radar display’. That said, even had WC1 selected the ‘pending’ Track, the ‘active’ Track information would still have been visible to them beneath the ‘pending’ track, if it had been displayed correctly by the UCCS. Flight plan information separate to the track information is selectable by the user in the UCCS and provides both a blue ‘flight plan line’ on the WC’s surveillance display and textual information on the Tote; however, this option does not seem to have been utilised by WC1, the FA or the MC to determine the B777’s routing. At 1845:20, the MC initiated a conversation with the FA over unrelated GAT “just west of Leeming and climbing to 28 and that’s going to conflict. That’s going to be a bit close…33 it’s going to be smack bang in the middle. That’s 5000 ft both ways, no margin for error.” The FA agreed that the unrelated GAT was going to conflict and replied “Okay, I he [sic] stops at 28, happy.” The MC then advised “It looks like it’s going up to 28 by the look of it and maintaining. I think a quick call to the civvies might help.” The FA then called WC1 suggesting that the developing situation “might be worth a call to the civvies otherwise you will be sandwiched between the 2 and no-one knows what’s going on.” The call ended at 1846:20 as WC1 advised the FA “I’ll call Montrose.” At this point, the B777 was 31.1nm SE of the Typhoon Formation, tracking NW’ly at FL380 with a Mode S SFL of FL260; the

Typhoon Formation was tracking SE’ly in 2.2nm trail, climbing through FL288 and 266 respectively.

WC1 then attempted to contact Montrose; however, there was no response, possibly as a result of Montrose attempting to contact WC1, through the FA. At 1846:39, WC1 connected into a call from Montrose, transferred to them by the FA, and initially heard a voice at Montrose saying “I know but you’ve got to because otherwise there’s no co-ordination mate, you’re en-route until further.” WC1 then identified their control position and Montrose replied “Hi Hotspur, information please 5-1-1-1, 1-2 squawks?” WC1 read back the squawks and a second voice on the Montrose

7

line stated “you need to avoid our 3-4-3-6 immediately, we’re descending FL 260 en-route.” As this was said, at 1846:59, the B777’s Mode S SFL changed to FL360, then at 1847:03 to FL380, in response to Montrose’s reported instruction to maintain FL380; the change to FL380 was

detected and displayed by UCCS at 1847:04. In addition, at 1847:00 it becomes evident on the radar replay that the B777 had commenced a slow turn to the right.

WC1 immediately replied “Descending 2-6-0? Hang on, left East” and instructed the Typhoon Formation “[c/s] Radar Control, turn left 0-9-0” which was acknowledged. At this point, the B777 was 18.8 nm SE of the Typhoon Formation, tracking NW’ly at FL380 with a Mode S SFL of FL380; the Typhoon Formation was tracking SE’ly in 1.5 nm trail, indicating through FL331 and a climb through FL325 respectively. Co-incident with the Typhoon Formation’s acknowledgement, the second voice at Montrose told WC1 “we’re going right on avoiding action, we’re turning right.” The landline exchange continued until 1848:02 when vertical coordination was achieved between both parties, with 7.1nm lateral and 5000ft vertical separation still existing at that point. During that exchange, it transpired that the Montrose controllers had observed the SSR Mode C of the trailing Typhoon indicate FL340, before SSR information was lost as the trail Typhoon joined formation with their leader and the pilot set the transponder to stand-by. Further analysis by CRC Hotspur determined that the trail Typhoon had not climbed above FL330. Analysis by NATS of the trail Typhoon’s SSR Mode C data determined that the aircraft had exceeded the 8000fpm Rate of Climb (RoC) Regulation4 from 1846:43, until SSR data was lost at 1847:05 as the pilot selected the transponder to standby. Moreover, the level information presented to the Montrose controllers by the NATS MRT system is predictive. Thus, when the trail Typhoon’s SSR data was lost, MRT extrapolated the Typhoon’s potential level based on the last known RoC and SSR Mode C data. Consequently, the Montrose controllers observed the trail Typhoon’s level read-out indicate a climb above FL330. This is a known issue with MRT. Following the Montrose controller’s instruction to the B777 to maintain FL380, separation was maintained throughout the incident sequence. This occurrence has highlighted a number of known latent conditions within our ATM system; specifically, the display of predictive level information by NATS’ MRT system, ergonomic issues with the representation of symbology on the UCCS display and a technical issue relating to dual-sensor tracking by the UCCS.

Comments

HQ Air Command

It appears that the Typhoon pair were in compliance with all ATC instructions and used their sensors to gain situational awareness of the B777 at considerable range. Other than the slight balloon through the cleared height, which was quickly corrected, there does not appear to be anything more that the miitary aircraft could have done.

Summary The Airprox occurred in Class C airspace, whilst the B777 was routeing on UAR UL602. The aircraft involved were being provided respectively with a RCS by the Montrose Sector and RAF Boulmer. The Boulmer controller believed that the B777 was maintaining FL380 so instructed the Typhoons to climb to FL330 in order to provide 5000ft separation. The Montrose T controller instructed the B777 to maintain FL380, planning to provide 5000ft separation against the Typhoons. When the 5111 squawk was passing FL325 and co-ordination had not yet been effected, the Montrose T controller, unsure whether the Typhoons would stop the climb at FL330, gave the B777 avoiding action to the right in order to comply with the Rules of the Air. Boulmer turned their traffic to the E due to potential conflicting traffic to the W. The Montrose T and P controllers believed that the 5111 squawk had climbed through FL330 due to the predictive element of MRT. The Mode C displayed on their

4 MMATM Chapter 12 Paragraphs 28-32.

8

situation displays briefly showed the 5111 squawk at FL339 although this was inaccurate. No loss of separation occurred. PART B: SUMMARY OF THE BOARD’S DISCUSSIONS Information available included reports from the pilots of the aircraft involved, radar recordings, transcripts of the relevant RT frequencies, reports from the air traffic controllers involved and reports from the appropriate ATC and operating authorities. The Board first considered the actions of the Boulmer controller. The ASACS advisor confirmed that the Boulmer Weapons controller (WC) was aware of the presence of the B777; however, the WC was not aware of the aircraft’s routeing or descent profile. The advisor briefed the Board that this was largely because of the mechanisation of the UCCS system and he gave the Board a brief description of the radar displays available to Boulmer WCs. The WC radar displays differ significantly from those provided to the civil controllers at the Prestwick Centre (PC) and this was a significant feature of this Airprox. On this occasion, the PC radar display showed the B777’s data block, including callsign, level, Selected Flight Level (SFL) and destination (the last two letters of the airport’s 4-letter code (EGPF), alongside the aircraft’s position. The WC display only showed Modes A and C alongside the aircraft. Additional information, including Mode S (SFL) was available, but only in a ‘tote’ displayed in the radar display’s top right-hand corner. This has to be interrogated to obtain the information. Although this was a quick procedure, the WC did not interrogate the ‘tote’ in the period leading up to the incident. Consequently, he was not aware, from the SFL, that the B777 pilot had been cleared for descent. The advisor commented that the range shown on the radar display could have been extended to show the aircraft’s intended track and destination. However, the WC believed that the B777 was on an overflying flight path and, therefore, would not be descending. A civil ATC area member, with experience of this airspace, commented that at the time of this Airprox (1845) it was unlikely that aircraft routeing NW to NATEB would be overflying i.e. it was outside the usual Oceanic operating times. The ASACS advisor commented that the WC was relatively inexperienced and would probably not have been aware of this information. He added that he was also occupied with another possible confliction in his operating area. Turning to the Montrose controller, approximately 1½min after clearing the B777 pilot to descend to FL260, he observed the Typhoons climbing towards the B777. He instructed the B777 pilot to maintain FL380. Although the pilot initially reported descending, he then advised maintaining FL380. The civil ATC area member added that it was fortuitous that the B777 had not descended earlier. In his experience, once aircraft on this route were given descent it was usually carried out expeditiously in order to meet any ATC level restrictions. Board members then considered the actions of the Typhoon pilots and, specifically, the rate of climb (ROC) of the trailing Typhoon as it was climbing towards the lead aircraft. In doing so, the trailing Typhoon pilot had exceeded the 8000fpm ROC limit, which was a contributory factor in influencing the Montrose controller’s thinking. Although the trail Typhoon pilot had in fact not climbed above FL330, due to the prediction algorithms of the NATS Multi Role Tracking (MRT) system, the Montrose controller’s radar display showed it passing FL340. As the MRT system is predictive; when the trailing Typhoon switched off Mode C (as it joined formation) with a high ROC, MRT extrapolated the last known ROC and SSR Mode C in order to generate a potential level which it calculated would be FL340. Having been presented with two fast-jet aircraft climbing rapidly towards his aircraft with no knowledge of their intentions, it was apparent to the Board members why the Montrose controller had decided to file an Airprox. However, his action to instruct the B777 to maintain FL380, and the co-ordination carried out with Boulmer for the Typhoons to maintain FL330, ensured that they remained separated by at least 5000ft vertically. It was therefore considered that although the incident met the criteria for reporting, normal procedures, safety standards and parameters pertained and it was determined that it would be misleading to consider this an Airprox occurrence.

9

PART C: ASSESSMENT OF CAUSE AND RISK Cause: A perceived conflict by the Montrose Sector controller. Degree of Risk: E. Contributory Factors: 1. One of the Typhoons exceeded 8000fpm rate of climb in CAS. 2. The Boulmer Weapons Controller assumed that the B777 would remain in

level flight. 3. The UCCS display mechanisation did not allow for display of destination

and did not facilitate ready display of Mode S. ERC Score5: 1


1


Position: 5359N 00130W (9.4nm WSW RAF Linton-on-Ouse)

Airspace: Vale of York AIAA (Class: G)


Type: Tucano T1 Socata TB20

Operator: HQ Air (Trg) Civ Pte

Alt/FL: 2400ft NK QFE (1025hPa) NK

Weather: IMC KLWD IMC KLWD

Visibility: 0km 0km


200ft V/0.5nm H NK


400ft V/0.1nm H


THE TUCANO PILOT reports recovering to RAF Linton-on-Ouse (LIN). The black and yellow ac had the SSR transponder selected on with Modes A and C; the lighting state was not reported. The ac was fitted with TCAS I. At the time of the Airprox the pilot was operating under IFR, IMC in cloud, with a Traffic Service from LIN APR. Prior to this, he was initially in VMC at FL120 when handed over to LIN APR from London Mil, 30nm on the 300R from LIN with a cloud layer estimated as base of 2000ft and cloud tops at 3000ft. He requested a Traffic Service and radar vectors for a PAR recovery and was instructed to descend to height 4000ft on the LIN QFE. He was then given a heading of 150°, updated to 145°. He was informed of traffic at a range of approximately 6nm at a position to the East of him, which he identified on TCAS, indicating 2000ft below. He was then instructed to descend to 2000ft and report cockpit checks complete. As he descended he entered cloud at 3000ft, becoming ‘fully IMC’ by 2800ft. At this point, heading 145° at 180kt and concentrating on his instrument scan, a TCAS alert sounded; he requested a Deconfliction Service and reduced the TCAS scale. ATC advised an immediate left turn onto North, which he implemented, at 2400ft, using 60° angle of bank, levelling off at 2300ft. At its closest point, the traffic indicated 200ft below and within 0.5nm on the TCAS display. ATC then called him clear of traffic and he completed the PAR without further incident. changing his intentions to land. The pilot noted that he ‘regained VMC’ at 2100ft but that he did not gain visual contact with the conflicting traffic at any point. He assessed the risk of collision as ‘High’. THE TB20 PILOT reports conducting a transit flight. The white and blue ac had navigation, beacon and strobe lights selected on, as was the SSR transponder with Modes A, C and S. The ac was not fitted with an ACAS. The pilot was operating under VFR initially. He and his passenger had planned the transit with the aid of a GPS map unit and initially took up their planned track, heading 316° at about 130kt and level below cloud at altitude 1300ft, some 2nm to the East of the Leeds Bradford International Airport (LBIA) CTR. This was confirmed by reference to the visible ground track and an NDB. After ‘exiting Fenton MATZ’ with Fenton APR, he contacted LBIA RAD, initially requesting a Traffic Service in order to climb through cloud to the planned cruise altitude of 4500ft, or FL65 if higher was required. He was instructed to standby and to remain outside CAS, which he did. He estimated that LBIA RAD agreed a Traffic Service when they were approximately 2nm West abeam the town of Wetherby, and that they were ‘fully IMC’ at 1400-1500ft in the climb. LBIA RAD passed


Tucano

CPA 1123:43400ft V/0.1nm H

TB20

1122:43

22:55

23:07

23:19

A037

A037

A027

A020

A012

23:31

A019

A013

A013

A014

A016

A016

A020 NM

0

1

2

2

TI, including details of opposite direction traffic in the descent. The pilot reminded LBIA RAD that he was ‘in solid IMC’ and stated he did not detect any sense of urgency in the controllers voice. He continued the climb, breaking out in to ‘clear air’ at 4000ft and continued to ‘the quadrantal cruise altitude’ of 4500ft. He and his passenger were unaware of an Airprox event until contacted by phone after the flight. THE LIN APR CONTROLLER reports he was bandboxing1 with DIR due to low traffic intensity. Weather conditions were good; colour code White2

with a layer of BKN cloud at 1800ft. He was controlling the Tucano pilot who had just been handed over from London at FL120. The Tucano pilot, being vectored for a PAR to RW03RH, was given Linton's weather and airfield details and a descent to height 4000ft due to the range from LIN. The LIN APR was monitoring ‘a Leeds squawk’, manoeuvring to the West of LIN, that was indicating 1000ft on Mode C. The Tucano pilot was descending to height 2000ft in accordance with the Radar Vector Chart and asked to report cockpit checks complete. Traffic information was passed to the Tucano pilot of an opposite direction contact, 12 o'clock, 4nm, indicating below but climbing. Traffic information was updated at 2nm with the track now indicating slightly below. The Tucano pilot requested a Deconfliction Service; an avoiding action turn onto a heading of 030° was issued. Once clear, vectors were given back ‘into the pattern’ and the Tucano pilot was handed over to DIR.

He perceived the severity of the incident as ‘Medium’. THE LIN SUP reports that, whilst he was in the VCR, the LIN APR had sent the DIR for a short break due to the low traffic levels. The SUP was content that the number of speaking units airborne would not cause an overload of capacity. The SUP was in the ACR during the occurrence. He stated he had remarked earlier that he was surprised that LBIA were ‘working a track’ outside their CTZ. However, due to it manoeuvring at low-level in Class G airspace, squawking with a verified Mode C, he elected not to call for traffic information. He was aware of the LIN APR vectoring the Tucano pilot for a PAR under a Traffic Service and heard the initial traffic information call. He noticed that the ‘Leeds track’ was now climbing and had taken up a reciprocal heading to the Tucano, which had commenced a descent to 2000ft. He therefore asked the LIN APR to amplify the traffic information with the ‘relative altitude difference in feet’. He then instructed the LIN APR to stop the Tucano’s descent as the rate of climb of the Leeds track had begun to increase. This instruction was not carried out as the Tucano pilot called the LIN APR almost immediately afterwards, requesting a Deconfliction Service. Avoiding action was passed and a separation of about 0.5nm was achieved, with the Mode C of the two aircraft indicating a difference of 200-400ft at CPA. An Airprox was not reported over RT at the time, but the Tucano pilot did subsequently file, after he had landed. Factual Background The weather for Leeds Bradford and RAF Linton-on-Ouse was recorded as follows:

METAR EGNM 111120Z 04004KT 320V130 9999 BKN015 14/10 Q1027= METAR EGXU 111050Z 32006KT 9000 HZ BKN018 16/11 Q1027 WHT BECMG FEW020 BLU=


CAA ATSI The incident occurred at 1123:42, 9.5nm to the SW of LIN, within Class G uncontrolled airspace, between a Tucano T1 and a Socata TB20 Trinidad. The Tucano pilot was in IMC, inbound to LIN in receipt of a Traffic Service from Linton Radar on a UHF frequency and was being vectored for a PAR recovery. Just prior to CPA, the Tucano pilot

1 Bandboxing is the practice of taking on the tasks of two ATC positions, traffic levels permitting. 2 Cloud base (at least 3/8 cloud) between 1500ft and 2500ft and/or visibility between 5km and 8km.

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requested a Deconfliction Service. The TB20 pilot was operating under IFR and was in IMC on a transit flight, in receipt of a Traffic Service from LBIA RAD on a VHF frequency. The workload of the LBIA controller was considered to be moderate. The TB20 pilot contacted LBIA RAD at 1118:29. He reported his location and routeing, stated he was climbing to 6500ft, and requesting transit clearance. The LBIA RAD replied, “[TB20 C/S] negative remain outside Leeds controlled airspace Leeds QNH one zero two seven you’re under a Basic Service”, which was acknowledged correctly. At 1120:49, the TB20 pilot requested, “…could you give us a Tr affic Service while we climb through cloud to get on top [TB20 C/S]”. The RAD responded, “Okay [TB20 C/S] squawk two six seven five”. This was read-back correctly and the TB20 pilot reported at 1000ft on 1027hPa just abeam Wetherby. The LBIA RAD advised, “Roger identified there about ten miles northeast east-northeast of Leeds under a reduced Traffic Service due to your altitude a-as you climb report when you’re VMC on top”. The TB20 pilot acknowledged, “Reduced Traffic Service until VMC on top ????? [TB20 C/S] thank you”. At 1122:00, the following RTF exchange between LBIA RAD and the TB20 pilot occurred:

RAD “and [TB20 C/S] there’s a contact er to the northwest of you there about er eight miles southeast bound indicating four thousand two hundred feet er with a climb arrow”

TB20 “I’ll try to keep a look out – just now going into cloud [TB20 C/S]. RAD “Roger thanks and er what level are you climbing to confirm” TB20 “Six thousand five hundred feet [TB20 C/S]” RAD “Roger the traffic just in your twelve o’clock six miles er opposite direction four thousand

feet indicated” TB20 “Copied [TB20 C/S]” RAD [1122:49] “[TB20 C/S] that er contact still in your twelve o’clock now four and a half miles

opposite direction indicating four thousand feet” TB20 “Keep a good l ookout just climbing through two thousand feet now on one zero two

seven” RAD “Roger”

The Tucano pilot’s written report indicated he was in receipt of radar vectors, heading 145°, in the descent to a height of 4000ft when he was advised of traffic 6nm away, which he reported was observed on TCAS 2000ft below. The Tucano pilot indicated that he was then instructed to descend to 2000ft by LIN APR. At 1123:09, the two aircraft were on reciprocal tracks at a range of 3nm, with the Tucano indicating FL027 (altitude 3100ft) and the TB20 FL013 (altitude 1700ft). The Tucano pilot’s written report indicated that in response to a TCAS TA he had requested a Deconfliction Service and was immediately advised to turn left onto North. At 1123:16, another aircraft called LBIA RAD and the controller replied “apologies last call again”. The LBIA RAD controller’s written report indicated that when next looking at the radar screen the two subject aircraft were a lot closer, at a separation range of 1nm and with 300ft vertical separation. The controller immediately passed updated traffic information as follows:

RAD [1123:25] “[Other aircraft C/S] standby break [TB20 C/S] the tr-contact twelve o’clock one mile indicating now two thousand three hundred feet” (see Figure 1).

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Figure 1 – Swanwick MRT at 1123:28

TB20 [1123:32] “Er that’s very close ma’am would you like us to stay on track or would you like me to turn left or right”. At 1123:36 the Tucano was at FL020 (altitude 2400ft) commencing the left turn and 0.6nm northwest of the TB20, which was at FL016 (altitude 2000ft), as shown in Figure 2 below.


At 1123:44 (CPA), the range between the two aircraft had reduced to 0.3nm with a vertical distance of 200ft as shown in Figure 3 below.

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At almost the same time, 1123:46, the following RTF exchange between LBIA RAD and the TB20 pilot occurred:

RAD “And that er contact now is turning northbound indicating two thousand three hundred feet now”

TB20 “We’ll maintain track on zero er three zero degrees” [note: It was likely the TB20 pilot meant to say 330 degrees, which was the aircraft’s track]

RAD “Okay it seems to be clearing to the northeast now” TB20 “???? copied [TB20 C/S]”.

At 1125:00, the TB20 pilot reported VMC on top in the climb, intending to level-off at altitude 4500ft.

At 1126:54, the TB20 pilot was advised that the Traffic Service was terminated and a Basic Service was agreed. The TB20 pilot was instructed to squawk 7000 before going en-route at 1134:20. CAP774 (UK Flight Information Services), Chapter 3 (Traffic Service), Page 1, paragraph 5, states:

‘The controller shall pass traffic information on relevant traffic, and shall update the traffic information if it continues to constitute a definite hazard, or if requested by the pilot...’

In Class G airspace, conflicting traffic may not be known to ATC and so it is necessary for all flights to make use of the 'see and avoid' principle. ATC will pass traffic information and instructions to assist pilots to 'see and avoid' each other. Both aircraft were IMC on a Traffic Service in an environment and conditions when it would have been appropriate for them to have agreed a Deconfliction Service. The LBIA RAD controller passed the TB20 pilot traffic information on the Tucano at a range of 8nm at 4200ft, with further updates as the range reduced to 6nm at 4000ft and at 4.5nm at 4000ft. At this point the vertical separation between the two aircraft was 2000ft. When the controller next looked at the situation the Tucano was descending on a reciprocal track at a range of 1.2nm and 300ft above the TB20. The controller immediately passed traffic information as a warning. The options available to the LBIA RAD at this late stage were very limited - had the controller considered giving avoiding action, the geometry of the situation would have dictated a right turn,

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in accordance with RoA (Rule 10 - converging head on), which would have increased the risk of collision as the Tucano had been turned left. CAP774, Chapter 3 (Traffic Service), Page 1, paragraph 6, states as follows:

‘Whether traffic information has been passed or not, a pilot is expected to discharge his collision avoidance responsibility without assistance from the controller. If after receiving traffic information, a pilot requires deconfliction advice, an upgrade to Deconfliction Service shall be requested.’

Paragraph 3 states as follows:

‘Pilots should be aware that a Traffic Service might not be appropriate for flight in IMC when other services are available.’

At a late stage the Tucano pilot requested a Deconfliction Service and the avoiding action left turn provided by LIN RAD, together with the swift action of the Tucano pilot in levelling off and making an immediate left turn with 60° of bank, was sufficient to resolve the conflict. The Tucano pilot reported that the TB20 passed within 0.5nm horizontally and 200ft below. Radar showed the minimum separation as 0.3nm laterally and 200ft vertically.

Military ATM This incident occurred 9.5nm WSW of LIN at 1123:41 on 11 Jul 13, between a Tucano and a TB20. The Tucano was recovering to LIN RW03RH for a PAR and was in receipt of a Traffic Service and latterly a Deconfliction Service from LIN APR. The TB20 pilot was operating under IFR, climbing to achieve VMC en-route and in receipt of a Traffic Service from LBIA RAD. All heights/altitudes quoted are based upon SSR Mode C from the radar replay unless otherwise stated. ‘Live-mic’ recording from the LIN SUP position was available to inform the investigation. LIN APR described their workload and task complexity as ‘low’ and was providing an ATS to one additional ac, along with the incident Tucano; the additional ac free-called LIN APR during the incident sequence for recovery to LIN. The incident sequence commenced at 1121:53 as the TB20 pilot began a slow climb from an indicated altitude of 700ft, tracking NW’ly, 9.8nm SE of the Tucano; the Tucano was heading 150°, indicating 3700ft (level 4000ft LIN QFE). Figure 1 depicts the geometry at this point; SSR 3A 4501 was the Tucano, SSR 3A 2675 was the TB20. Prior to the start of the incident sequence and until 1122:31, LIN APR was involved in a continuous exchange with an un-related Tucano free-calling for a PAR recovery, 21.3nm NNE of LIN and 25.1nm NE of the incident Tucano.

Figure 1: Incident Geometry at 1121:53.

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At 1121:15, LIN SUP was recorded asking “why are Leeds controlling that?”, a question linked to their reported comment that they were ‘surprised that LBIA were working a track outside of their CTZ’. However, due to it manoeuvring at low level in Class G, LIN elected not to call for TI as it was squawking with a verified Mode C. This is borne out on the transcript by the SUP’s question. Having completed the initial actions with the un-related Tucano, at 1122:34, LIN APR instructed the incident Tucano to “descend to height 2000ft, cockpit checks report complete” which was acknowledged; Figure 2 depicts the incident geometry at this point with the TB20’s RoC being about 590fpm.


The guidance material to CAP774 Chapter 3 (Traffic Service), paragraph 6 states that ‘when providing headings/levels for the purpose of positioning and/or sequencing or as navigational assistance, the controller should take into account traffic in the immediate vicinity, so that a risk of collision is not knowingly introduced by the instructions passed’. At 1122:47, LIN APR advised the Tucano of “traffic 12 o’clock, 4 miles, opposite direction, indicating below, climbing” which was acknowledged at 1122:52; Figure 3 depicts the incident geometry at this point.

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Figure 3: Incident Geometry at 1122:47. Based upon the report of the LIN SUP, this was the point at which he became aware of the developing situation, immediately advising LIN APR to “tell him how far below because he’ll go D-S on you.” This was a reference to LIN APR’s use of “below” to describe the TB20’s level, rather than using the phraseology contained within CAP413, Chapter 5, paragraph 1.63

. The Tucano pilot commenced descent at 1122:59 and indicated passing 3000ft LIN QFE at 1123:06; approximately the time at which he entered IMC.

The guidance material to CAP774, Chapter 3 (Traffic Service), paragraph 5 states that ‘controllers shall aim to pass information on relevant traffic before the conflicting aircraft is within 5 NM, in order to give the pilot sufficient time to meet his collision avoidance responsibilities and to allow for an update in traffic information if considered necessary’. MMATM, Chapter 11, paragraph 26 states that ‘when the prevailing circumstances suit the use of only approximate level information (ie slightly above/below, above/below, well above/below), the following may be used as guidance: a. Slightly above/below - vertical difference up to 1000 ft. b. Above/below - vertical difference of between 1000 ft and 3000 ft.

c. Well above/below - vertical difference exceeding 3000 ft (such information would normally be irrelevant but could be of importance, eg, if a high rate of climb or descent is involved)’

However, the MMATM does not give examples of circumstances in which only approximate level information may be used or useful. Moreover, this reference is at odds with CAP413, Chapter 5, paragraph 1.6 which provides the phraseology that ‘should’ be used ‘whenever practicable’ and it is noteworthy that the guidance within the MMATM is not incorporated within CAP493. The guidance material to CAP774, Chapter 3 (Traffic Service), paragraph 3 states that ‘pilots should be aware that a TS might not be appropriate for flight in IMC when other services are available’. About 10sec after the SUP’s advice to LIN APR, at 1123:10, LIN APR updated the TI to the Tucano pilot advising him “previously called traffic 12 o’clock, 2 miles, opposite direction, indicating 1000 ft below, climbing”. At this point, the TB20 was 2.7nm SE of the Tucano, tracking NW’ly, indicating a climb through 1300ft; the Tucano was heading 150° and indicating a descent through 2500 ft (about 2200ft LIN QFE). Based on the Tucano pilot’s report, this TI was almost co-incident with the receipt of a TCAS TA. As LIN APR was finishing their TI transmission and prompted by a perceived increase in the TB20’s RoC, LIN SUP instructed APP to “stop his descent [name of LIN APR] you’re about to descend him to him”. However, LIN SUP was interrupted by the Tucano pilot’s request for a DS. LIN APR immediately advised the Tucano “avoiding action, turn left immediately heading 0-3-0 degrees, traffic was 12 o’clock, 1 mile, opposite direction, indicating slightly below, climbing”. The pilot read-back “left 3-6-0 degrees” and whilst this error was not corrected by LIN APR, it was neither a causal nor contributory factor in this Airprox. It is worth highlighting that guidance for controllers on the provision of ATS to solo student pilots is to ‘avoid complex instructions’ and that it is considered ‘good practice’ not to include instructions to turn and climb in the same transmission. Thus, given that the TB20 was climbing, LIN APR correctly prioritised issuing lateral avoiding action to break the conflict, rather than to instruct a ‘level-off’ or a climb. Figure 4 depicts the incident geometry at 1123:20, the point that LIN APR passed the deconfliction advice, and is an approximation of LIN APR’s surveillance picture in the immediate vicinity of the Airprox.

3 CAP413 … 1.6.2 states : c) (when giving traffic information to an aircraft which is climbing or descending) ‘… 1000 feet above/below cleared level.’

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At this point, 2nm lateral separation existed between the 2 ac, with the Tucano 4nm E of the edge of the LBIA CTR.


Albeit that the TB20 indicated 1700ft for one radar sweep at 1123:34, analysis of the radar replay showed that the TB20 indicated level at 1600ft from 1123:30 until after the CPA. The Tucano pilot’s response to the deconfliction advice was visible on the radar replay at 1123:39; Figures 5 and 6 show the incident geometry on the radar sweep immediately prior to the Tucano’s left turn (1123:36) and the second sweep after the initial turn.


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Although some track jitter is evident, the CPA occurred between radar sweeps at approx 1123:41 as the Tucano passed about 0.3nm N of the TB20, with 400 ft vertical separation indicated. The CPA was 6.7nm NW the LIN RW03RH centreline and 4.3nm E of the boundary of the LBIA CTR. In their Airprox report, the TB20 crew related that it ‘may have been better, as we were staying outside Leeds zone, to have gone to Linton Radar...coverage of which is suggested on the portions of the map we were flying over’. UK AIP ENR 1-6-3-3-1 states that ‘pilots intending to use the LARS should note the participating ATS Units close to their intended track and...when within approximately 40 nm of a participating ATS Unit, establish two-way RTF communication on the appropriate frequency’. UK AIP ENR 6-1-6-3 depicts LARS coverage in the UK and states that the relevant LARS ATS provider in that area is LIN. Turning first to the timing of initial TI to the Tucano, although slightly late, given that the relative speeds of the ac involved were such that 54sec elapsed between this TI and the CPA, this was neither a causal nor a contributory factor in this Airprox. Whilst with hindsight the avoiding action turn to the left required the Tucano to cross the TB20’s nose, given the Tucano’s proximity to the LBIA CTR and the surveillance display picture presented to LIN APR at the time, LIN APR’s advice was understandable. Moreover, the reduced lateral separation at the time of the Tucano pilot’s request for DS placed LIN APR in a difficult situation. Although the student pilot’s decision to request a DS was sound, his decision to descend into IMC in receipt of a TS, having been made aware of conflicting traffic, was less so. An earlier request for a DS, prior to entering IMC, would have permitted LIN APR to have provided deconfliction advice that would have achieved greater lateral separation than existed at the CPA. Moreover, whilst a delay in the student pilot’s commencement of the avoiding action was understandable given the flight conditions and his experience level, the approximately 10sec delay, coupled with the timing of the deconfliction advice, served to drastically reduce safety margins. The conflict was resolved by the student pilot following the deconfliction advice issued by LIN APR, coupled with the ‘fortuitous’ levelling-off by the TB20 pilot. With regards to the timing of the pilot’s request for a DS, this Airprox was similar to Airprox 2013067; a fact commented upon both by the Tucano Squadron Standardisation Officer and the Officer Commanding the Tucano Squadron and is linked to a previous recommendation from RAF FS to the CFS to review teaching of ATSOCAS to RAF aircrews. Given the incident geometry that existed at 1122:34 and that LIN APR was aware of the TB20’s presence and climb, it is reasonable to argue that the instruction to the Tucano pilot to “descend to height 2000ft” introduced a risk of collision. Whilst cognisant that the ‘pilot is expected to discharge his collision avoidance responsibility without assistance from the controller’, given the

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weather in the local area and that the TB20 was continuing its climb, a more defensive controlling technique on the part of LIN APR may have reduced the severity of this Airprox. With regards to the differences highlighted between MMATM, Chapter 11, paragraph 26; CAP 413, Chapter 5, paragraph 1.6 and CAP 493, BM SPA have requested that the MAA review the content of the MMATM to determine whether this guidance remains extant.

Comments

HQ Air Command Air Command endorse the comments of the Military ATM investigator. The recommendation for a 22 Trg Gp review of aircrew training in ATSOCAS is still outstanding due to resource issues. It nevertheless is crucial to identify the reason for aircrews choosing to operate in IMC under a TS when a DS might be much more appropriate. The pilot had complied with the regulations, which merely require a Radar Service (TS or DS) when IMC in most circumstances. His decision to upgrade to a DS was appropriate, albeit late, and his reaction to the avoiding action was as timely as could reasonably be expected from the solo student pilot; the TB20 pilot may also have taken action by levelling off in reaction to his TI. However, the incident highlights the limitations of such a methodology as a means of providing safe separation when IMC and should serve as a lesson to all those who perceive it to be an acceptable way to operate. The UKAB recommendation to the MAA following Airprox 2013067 (to consider providing advice on the wisdom of not taking a DS in IMC) may go some way to changing attitudes. However, the ‘social acceptability’ of operating IMC under a TS must be challenged, particularly when under vectors and when a DS is not operationally limiting. RAF FS issued a Safety Note following Airprox 2013067 and will issue a further one following the UKAB’s consideration of this event. RAF FS will also continue to work with the CAA and MAA on the content of CAPs 413 and 774 and recommends that the following paragraph is added to guidance contained in CAP774:

‘Conflicts that materialise after an instruction has been passed will be called in accordance with the service being provided. Controllers are only required to amend instructions to achieve Deconfliction Minima where a DS is being provided.’

Summary A Tucano and a TB20 flew into conflict at 1124 on 11th July 2013 at a position 9.4nm WSW of LIN. The incident occurred when the Tucano pilot (IMC and in receipt of a Traffic Service from LIN APR) descended towards the TB20 which was climbing on a reciprocal track (also IMC and in receipt of a Traffic Service from LBIA RAD). Under the terms of their selected ATS, both pilots were ultimately and equally responsible for collision avoidance.


Information available included reports from the pilots of both ac, transcripts of the relevant RT frequencies, radar photographs/video recordings, reports from the air traffic controllers involved and reports from the appropriate ATC and operating authorities. The Board first considered the application of ATS. A Traffic Service had been correctly agreed with both pilots, albeit with different ATSUs. The LBIA RAD workload was considered ‘moderate’ and the LIN APR described his workload and task complexity as ‘low’. LBIA RAD passed TI to the TB20 pilot on the Tucano in the 12 o’clock, opposite direction, at ranges of 6nm and 4.5nm. Crucially, although this latter TI was some 15sec after the Tucano pilot had been instructed to descend, the change in altitude was not yet apparent on the LBIA radar display. Hence the Tucano was described as being ‘at 4000ft’. The Tucano pilot received TI on the TB20 (shortly after being instructed to descend), in his 12 o’clock at a range of 4nm, below him and climbing. ATC members, both civil and military, opined that it was apparent from the recorded LIN SUP comments that he had identified the juxtaposition of the two aircraft and was anticipating a request for a Deconfliction Service from the Tucano pilot; the

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Board therefore felt that the situation could have been handled more proactively if the Supervisor had felt able to suggest a Deconfliction Service to the Tucano pilot. Members spent some time discussing the application of a Traffic Service in IMC and concluded that although CAP774 states4

:

‘The controller shall pass traffic information on relevant traffic, and shall update the traffic information if it continues to constitute a definite hazard, or if requested by the pilot...’

The reality was that the controllers may not always be able to do so. Indeed, the next paragraph of CAP774 states:

‘Whether traffic information has been passed or not, a pilot is expected to discharge his collision avoidance responsibility without assistance from the controller. If after receiving traffic information, a pilot requires deconfliction advice, an upgrade to Deconfliction Service shall be requested.’

The Board opined that it was patently not possible for a pilot to discharge his collision avoidance responsibility without assistance from the controller when flying in cloud and without the aid of a collision avoidance or warning system. Additionally, even with such a collision avoidance system it was felt that many pilots (and especially inexperienced pilots) would find it challenging to fly by sole reference to instruments whilst also assimilating TI and manoeuvering correctly to avoid traffic that they assessed to be conflicting. Members therefore opined that a Deconfliction Service was a far more suitable ATS for flight in cloud. Turning to the pilots’ actions, the Board considered that the TB20 pilot had planned his transit conscientiously but that he would have been better served by contacting LIN LARS after leaving the RAF Church Fenton MATZ rather than LBIA. This would have afforded the required level of coordination between LIN traffic, and TI could have been passed to LBIA on request. There was some doubt from members as to the level of understanding of the agreed Traffic Service by the TB20 pilot. He was apparently aware of the developing conflict, albeit at a late stage, but his comment, ““Er that’s very close ma’am would you like us to stay on track or would you like me to turn left or right”, some 11sec before CPA, indicated that he may not have been fully aware of his collision avoidance responsibility under CAP774, as quoted above. Members stated that misunderstanding of the ATSOCAS regulations seemed to be a common feature of many Airprox. For his part, the Tucano pilot was operating with an agreed Traffic Service and did not request a Deconfliction Service until about 23sec before CPA. He had apparently become increasingly concerned by the developing conflict, reinforced by his TCAS information, which culminated in the last TI call and his late request for a Deconfliction Service. Members opined that he would have been better placed by requesting a Deconfliction Service before entering cloud, hence allowing the controller sufficient time and space to sequence him and achieve deconfliction. The Tucano pilot reacted to the instruction to carry out avoiding action by rapidly levelling off and entering a steep turn to the left whilst flying under IMC on instruments; although it is easy to be wise after the event, some Board members opined that this carried significant risks of its own with respect to disorientation. When assessing the cause, members noted that the Tucano pilot had been given a vector, whereas the TB20 pilot was flying ‘own navigation’. The onus therefore rested on the LIN RAD controller who, it was opined, had descended the Tucano pilot into conflict with the TB20 that was visible on his radar display. The Board also opined that both pilots were in receipt of an inappropriate ATS for their flight conditions and noted that the TB20 pilot was not in contact with LIN LARS and that these were both contributory causes. Overall, it was felt that safety margins had been much reduced below normal and a Risk Category of B was therefore awarded. The Board also agreed a number of recommendations; firstly to examine pilot education with respect to ATSOCAS regulations and the specific benefits of a Deconfliction Service whilst operating in IMC, secondly to review the adequacy of guidance for the provision of level allocation to pilots under a Traffic Service, and thirdly to review harmonisation of military and civil RT phraseology.

4 Chapter 3 (Traffic Service), Page 1, paragraph 5.

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Cause

: The Linton controller descended the Tucano pilot in to conflict with the TB20.

Contributory Factor(s) 2. The TB20 pilot was not in contact with Linton LARS.

: 1. Both pilots were under an inappropriate ATS for the flight conditions.

Degree of Risk

: B.

ERC Score5

: 4.

Recommendation(s)

: 1. The CAA reviews the education of ATSOCAS and specifically the benefits of DS in IMC, and that the MAA address this same issue through each Front Line Command.

2. The CAA and MAA review the adequacy of guidance for the provision of level allocation to pilots under a TS.

3. The MAA reviews harmonisation of MMATM and CAP413 phraseology.


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AIRPROX REPORT No 2013072 Date/Time: 14 Jul 2013 1119Z (Sunday)

Position: 5203N 00034W (OH Ridgewell Gliding Site)

Airspace: London FIR (Class: G)


Type: ASW20 Glider Aquila A210

Operator: Civ Club Civ Trg

Alt/FL: 500ft 1200ft agl NK

Weather: VMC NK VMC NK

Visibility: 5nm >10km


200ft V/0ft H NK


NK


THE ASW20 PILOT reports flying his white, mid-wing, glider, with no lights fitted from Ridgewell gliding site. Five minutes after a winch-launch to 800ft he was in a continuous left-hand turn, 300m south of the landing strip, passing north, with 45° of bank, at 50kts, overhead the airfield, staying level at 500ft in weak rising air. He saw the A210 heading approximately 140°, crossing the landing strip and heading directly toward his glider. Approximately 4sec after the first sighting, the A210 passed ‘about 200ft’ above the ASW20; the glider pilot reports that his aircraft takes several seconds to roll from a 45° left-bank to a 45° right-bank, consequently he decided there was insufficient time for him to reverse his turn and he assessed that ‘an emergency dive was not justified’. He lost sight of the other aircraft and then regained visual contact as his glider passed through south and he was able to see the other aircraft continue on a s traight, south-easterly course. O ther members of the gliding club, observing from the ground, were not able to read the A210’s registration but were able to note its ‘crescent’ shaped leading edge. THE A210 PILOT reports flying a mainly white aircraft VFR at 1200ft, he thought, but did not report his pressure setting. He was cruising at 100kt squawking Mode 3/A 7000 with Mode C turned on but he did not see the glider, and so was unable to describe the circumstances of the Airprox. Factual Background The METAR for Cambridge (15nm west-north-west of Ridgewell) at 1120 was: METAR EGSC 141120Z VRB05KT 6000 BKN013 21/16 Q1024 Ridgewell gliding site is notified as a gliding site in the UK AIP en-route 5.5 and is also indicated on the 1:250,000 and 1:500,000 series maps by a standard gliding site symbol which shows the site elevation as 273ft amsl and the maximum altitude of the winch launch as 2300ft amsl (UKAB Note 1: approx 2000ft agl).

A2101000ft alt

Possible ASW20 primary returns

in this area


Wethersfield

NM

0 1

2

Analysis and Investigation UKAB Secretariat The radar recording showed the A210 passing directly overhead Ridgewell gliding site at 1119:10, squawking Mode 3/A 7000, tracking south-east, indicating an al titude of 1000ft and a gr ound-speed of 103kt. Given that Ridgewell gliding site is 273ft amsl, this indicates that the A210’s height was approximately 727ft, which is commensurate with the ASW20 pilot’s report of around 200ft minimum vertical separation. A primary radar return can be observed intermittently in the Ridgewell overhead just prior to the Airprox but it cannot be positively identified as the ASW20; consequently, there was no recorded vertical or horizontal separation.

Summary An Airprox occurred in Class G airspace overhead Ridgewell gliding site between an ASW20 glider and an A210; both aircraft were flying VFR.

PART B: SUMMARY OF THE BOARD’S DISCUSSIONS

The gliding and GA members opined that the A210 pilot appeared to have either planned his flight to pass over the gliding site (through the circuit and well below the winch height), or that he had not planned well enough and w as unaware of the gliding site. Both options were seen as equally dangerous and a fatal crash would almost certainly have been the result of his aircraft hitting the winch cable or a launching glider. The gliding member advised that pilots should always plan to keep well clear of gliding sites, keeping a good lookout for gliders and tugs which can be launching gliders or returning to the site with trailing tow-ropes. The Board opined that the annotation of Glider RTF on VFR charts and within the AIP ENR5.5, would greatly assist in this respect by providing a readily available contact frequency for those GA pilots who planned to fly close to glider sites, and who wished to determine their levels of gliding activity. When aircraft are converging, powered aircraft are required to give way to gliders1. When flying in the vicinity of what pilots ought reasonably to know is an aerodrome, they are required to conform to the pattern of traffic intending to land, or keep clear of the airspace in which the pattern is formed2

. The patterns flown by gliders can vary substantially from those of other aircraft, and the gliding members advised that the best way to comply with this Rule is to avoid notified gliding sites by a wide margin. When wishing to fly past gliding sites at lower altitudes, the gliding member advised that pilots should consider ensuring sufficient horizontal distance from the site to remain below an average glide angle of 30:1 (about 200ft per nm, which would be achievable at the minimum 500ft separation from the ground at a distance of 2.5nm from the site). It was also noted that many of the larger gliding sites can have winching up to 3000ft agl.

Ridgewell is marked as a gliding site on the 1:250,000 and 1 :500,000 series charts and so it is reasonable to expect the A210 pilot to have known of its presence; he would have been prudent to have given the site a w ider berth, especially as he w as flying at around normal circuit height. In addition, the onus was on the A210 pilot to give way to the glider, although the lack of any enhanced conspicuity features on both aircraft would have made visual acquisition by both pilots more difficult. Although there was likely to have been around 200ft between the aircraft, the A210 flew directly over the gliding site and over the ASW20, whose pilot had few options to avoid the other aircraft. The A210 pilot did not see the glider; the glider pilot saw the A210 and assessed that his flight path would keep him clear, albeit with safety margins much reduced below the normal. The Board concurred and assessed the Risk as B. The barriers pertinent to this Airprox were: ‘Aircrew rules and pr ocedures’, ‘visual sighting’ and ‘aircrew action’. Because the A210 pilot did not see the ASW20, and so could not give way, and the

1 Rules of the Air 2007 (as amended), Rule 9 (Converging). 2 Rules of the Air 2007(as amended), , Rule 12 (Flight in the vicinity of an aerodrome).

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ASW20 pilot saw the A210 so late that his only remaining course of action would have been to make an avoiding action dive, the remaining barriers were assessed at being ‘minimally’ effective. The A210 had 2 POB and the ASW20 had 1 POB so the ERC score was assessed as 20.


Cause

: The A210 pilot flew over a promulgated and active glider site, below the notified winch-launch altitude, and into conflict with the ASW20, which he did not see.

Degree of Risk

: B

ERC Score3

: 20

Recommendations

:

1. The CAA reviews annotation of gliding RTF on VFR charts and the AIP ENR5.5. 2. The CAA reviews the education of GA pilots regarding overall awareness of gliding operations with specific emphasis on flight in the vicinity of glider sites.


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AIRPROX REPORT No 2013073 Date/Time: 13 Jul 2013 1124Z (Saturday)

Position: 5224N 00048E (3.3nm ENE RAF Honington)

Airspace: Lon FIR (Class: G)


Type: Vigilant T1 PA28


Alt/FL: 2600ft 2500ft QNH (NK hPa) QNH (NK hPa)

Weather: VMC CLBC VMC CLOC

Visibility: 30km >10km


100ft V/0ft H Not Seen


NK V/<0.1nm H


THE VIGILANT PILOT reports conducting an instructional sortie. The white, red and orange ‘day-glow’ ac had navigation lights, landing light and HISL selected on, as was the SSR transponder with Mode A only. The ac was not fitted with an ACAS. The pilot was operating under VFR in VMC with a Basic Service from Lakenheath APR on VHF radio. He ‘switched to Lakenheath QNH’ and climbed to 2500ft where he started instruction. He was 1nm SW of holding point ‘Yankee’, pointing out the identifying features of the holding point, with the ac in a medium turn to the R at 60kt, turning through heading 360°, when a blue and white ‘Piper Cherokee type’ ac, with ‘strobes and nav lights on’, was seen directly overhead, about 100ft above. The ac came from his 8 o'clock position, heading NE, in straight and level flight. The registration could not be seen. Lakenheath Approach were contacted by telephone after the flight and he was informed that TI had been passed. Neither he nor the trainee recalled hearing any TI calls. A mute switch was fitted to the ac, but was not used during the flight. He assessed the risk of collision as ‘Medium’. THE P28 PILOT reports transiting in level cruise. The white, green and gold ac had the SSR transponder selected on with Modes A and C. The lighting state was not reported; the ac was not fitted with an ACAS. The pilot was operating under VFR in VMC, in good visibility with little or no low cloud, and with a Basic Service from Lakenheath APR on VHF radio, he thought. The pilot stated that the flight progressed without memorable incident to either himself or his passenger. As with all flights, a good lookout was maintained with occasional minor course deviations when other traffic was seen. He noted that he very often operated from what was primarily a gliding site and was very aware of gliding traffic and the need to ‘keep a very sharp lookout’. He did not recall any instances of risk of collision on this flight. He was aware of a number of gliding sites on the route, and had planned to climb to about 3500ft approaching Tibenham (Priory Field) gliding site. During the part of the flight to the East of Cambridge, heading 072° at 105kt, he was in contact with Lakenheath APR, ‘with a Basic Service’. He did not recall RT traffic being particularly heavy and on leaving the ‘radar service’ he contacted his destination. THE LAKENHEATH APR CONTROLLER did not file a report but a transcript of the VHF RT was provided, as follows:


PA282800ft alt

CPA 1123:42NK V < 0.1nm H

Vigilant

23:1823:30

23:0622:541122:42

NM

0 1

2

From To Transcribed Speech Time

PA28 APR Lakenheath good morning [PA28 C/S] 1110:40

APR PA28 [PA28 C/S] Lakenheath departure squawk zero four five three 1110:45

PA28 APR [PA28 C/S] say again 1110:52

APR PA28 [PA28 C/S] squawk zero four five three 1110:59

PA28 APR zero four five three [PA28 C/S] 1110:59

PA28 APR [PA28 C/S] squawking zero four five three 1111:08

APR PA28 [PA28 C/S] pass your details 1111:19

PA28 APR [PA28 C/S] PA28 out of *** [departure airfield] uh we just passed uh overhead of Ca-Cambridge *** of the zero seven two of the charlie foxtrot delta, two passengers on board, two two zero zero, two two zero zero feet, one zero two four for MATZ penetration please

1111:23

APR PA28 [PA28 C/S] roger, MATZ penetration is approved, remain clear of Lakenheath, Mildenhall A T Z’s ***

1111:41

PA28 APR Roger understand the MATZ penetration approved, can you say the rest of the part of your message please slowly

1111:47

APR PA28 Yes sir, remain clear of the Lakenheath, Mildenhall A T Z. Lakenheath Q N H one zero two three

1111:53

PA28 APR One zero two three remain clear of the uh A T Z [PA28 C/S], thank you 1111:59

Other traffic 1112:02

Vigilant APR Lakenheath approach [Vigilant C/S] 1113:19

APR Vigilant [Vigilant C/S] Lakenheath 1113:32

Vigilant APR Wattisham radio [Vigilant C/S] is a military glider flying out of Honington, two P O B, requesting basic service

1113:40

APR Vigilant [Vigilant C/S] what altitude will you be climbing to 1113:53

Vigilant APR *** six thousand feet north of the airfield 1114:00

APR Vigilant [Vigilant C/S] roger squawk zero four five four 1114:08

Vigilant APR Squawk zero four five four [Vigilant C/S] 1114:14

APR Vigilant [Vigilant C/S] you’re radar contact under basic service, Lakenheath Q N H is one zero two three

1114:17

Vigilant APR One zero two three uh [Vigilant C/S] 1114:26

Vigilant APR Lakenheath approach I’m climbing to two and a half thousand feet 1115:01

APR Vigilant Copy that [Vigilant C/S] 1115:06

APR PA28 [PA28 C/S] traffic eleven o’clock ten miles is a glider at operating in the vicinity of Honington, climbing to two thousand five hundred feet

1115:28


APR PA28 [PA28 C/S] exiting my airspace to radar services terminated, frequency change approved squawk seven thousand

1129:27

PA28 APR Uh [PA28 C/S] were you calling me sir 1129:50

APR PA28 [PA28 C/S] affirmative you’re exiting my airspace to the east, squawk seven thousand, radar services terminated, frequency change approved

1130:03

3

From To Transcribed Speech Time

PA28 APR [PA28 C/S] roger say again squawk 1130:08

APR PA28 VFR seven thousand sir 1130:12

PA28 APR Seven thousand roger good day 1130:13


Vigilant APR Lakenheath approach uh 1134:13

Vigilant APR Lakenheath approach [Vigilant C/S] returning to Honington, request frequency change to one two two point one and transponder change to zero four six three

1134:20

APR Vigilant [Vigilant C/S] approved as requested, radar services terminated 1134:34

Vigilant APR Thank you [Vigilant C/S] 1134:41

Factual Background The RAF Marham weather was recorded as follows:

METAR EGYM 131050Z AUTO 36008KT 9999 NCD 26/17 Q1024 METAR EGYM 131150Z AUTO 34009KT 9999 NCD 27/16 Q1024

The Norwich airfield weather was recorded as follows:

METAR EGSH 131120Z VRB03KT CAVOK 25/15 Q1024 NOSIG Analysis and Investigation

UKAB Secretariat Both pilots were operating under VFR in Class G airspace and were equally responsible for collision avoidance1. The Vigilant pilot was in receipt of a Basic Service from the Lakenheath APR. The PA28 pilot was in communication with Lakenheath APR, however, although he was issued with a squawk and given TI, no ATS was formally agreed. The aircraft crossed flight paths twice; the first time, at about 1123:18, the PA28, heading ENE, crossed 0.2nm behind the Vigilant, heading SE; the second, with the PA28 and Vigilant heading E and NE respectively, at the CPA with the radar showing the tracks within 0.1nm. Although the Vigilant pilot described his flight path as a medium turn to the right, from the proximity of the SSR it is assumed that the second crossing was the reported Airprox. It was considered that the Vigilant pilot had right of way2

Figure 1: Area radar picture at 1115:28

. Although the Vigilant pilot reported that Lakenheath APR told him after his flight that TI had been passed, the transcript shows that TI was passed to the PA28 pilot only, at 1115:28, some 8min before the CPA (see Figure 1).

1 Rules of the Air 2007 (as amended), Rule 8 (Avoiding aerial collisions) 2 Rules of the Air 2007 (as amended), either Rule 11 (Overtaking).

4

A Basic Service is defined3

as follows:

‘A Basic Service is an ATS provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights. This may include weather information, changes of serviceability of facilities, conditions at aerodromes, general airspace activity information, and any other information likely to affect safety. The avoidance of other traffic is solely the pilot’s responsibility.

Basic Service relies on the pilot avoiding other traffic, unaided by controllers/FISOs. It is essential that a pilot receiving this service remains alert to the fact that, unlike a Traffic Service and a Deconfliction Service, the provider of a Basic Service is not required to monitor the flight’

The provision of Traffic Information and Deconfliction under a Basic Service is defined4

as follows:

Pilots should not expect any form of traffic information from a controller/FISO, as there is no such obligation placed on the controller/FISO under a Basic Service outside an Aerodrome Traffic Zone (ATZ), and the pilot remains responsible for collision avoidance at all times. However, on initial contact the controller/FISO may provide traffic information in general terms to assist with the pilot’s situational awareness. This will not normally be updated by the controller/FISO unless the situation has changed markedly, or the pilot requests an update. A controller with access to surveillance-derived information shall avoid the routine provision of traffic information on specific aircraft, and a pilot who considers that he requires such a regular flow of specific traffic information shall request a Traffic Service. However, if a controller/ FISO considers that a definite risk of collision exists, a warning may be issued to the pilot.

Traffic information in general terms could include warnings of aerial activity in a particular location, e.g. “Intense gliding activity over Smallville”.

In order to comply with the Rules of the Air Regulations 2007 ( as amended) with regard to flight within an A TZ, specific and, where appropriate, updated traffic information will be provided to aircraft receiving Aerodrome Air Traffic Services.

Comments

HQ Air Command Given that the PA28 pilot reports making ‘occasional minor course deviations when other traffic was seen,’ and his deviation to the left at 1123:05, it is possible that he initially sighted and avoided the Vigilant. However, given the eventual proximity and reported height separation, it seems very unlikely that he maintained this sighting until the CPA. The Vigilant pilot’s report of the incident geometry is hard to correlate to the radar trace but it is clear that his sighting only occurred as the PA28 passed overhead. He points out in his report that he was dividing his attention between instructing, pointing out ground features and lookout; once he had turned left, away from the approaching PA28, his chances of sighting it were very much reduced. The program to fit Vigilant with PowerFLARM5

is in progress and should improve awareness of proximate transponding and FLARM-equipped aircraft. This should reduce the impact of similar late/non-sighting events.

USAFE The Lakenheath RAPCON6

3 CAP774 (UK Flight Information Services) dated 19th November 2009, Chapter 2 (Basic Service), paragraph 1 (Definition)

place all crossers of the Lakenheath/Mildenhall CMATZ under a Basic Service, or higher if necessary, as a matter of routine; the controller's omission to state the service to the PA28 was an error but the intended service was clear from the traffic information passed on

4 ibid. paragraph 5 (Traffic Information) and paragraph 6 (Deconfliction). 5 http://www.powerflarm.aero/index.php/en/technology/traffic-detection 6 Radar Approach Control.

5

the Vigilant. While the RAPCON controller applied a Basic Service in accordance with its definition, the tracks and ultimate proximity of the 2 aircraft indicate that additional traffic information to both aircraft should have been considered. The Unit is addressing the matter.

Summary A Vigilant T1 and a PA28 flew into confliction at 1124 on 13th July 2013, 3.3nm ENE of RAF Honington. The Vigilant pilot was in receipt of a Basic Service from Lakenheath APR; the PA28 pilot was in communication with Lakenheath APR but was not in receipt of an agreed ATS. He received one TI call on the Vigilant 8min before CPA but he did not see it and continued en-route at about 1130. The Vigilant pilot did not report the Airprox on the RTF in use but did so after landing.


Information available included reports from the pilots of both ac, a transcript of the relevant RT frequency and radar video recordings. The Board first considered the pilots’ actions, noting that they were equally responsible for collision avoidance, and that the Vigilant pilot had right of way as the aircraft being overtaken. The PA28 pilot had given some consideration to his planned flight but was not in receipt of an ATS type that could have materially assisted with his collision avoidance responsibility. The Board noted that although an ATS had not been agreed, the PA28 pilot was, in effect, in receipt of a Basic Service. The Vigilant pilot did not see the PA28 until it was directly overhead, too late to take any avoiding action. The Vigilant pilot was faced with the competing requirements for a cockpit environment quiet enough for effective instruction and collision avoidance assistance, normally provided by a Traffic or Deconfliction Service. On this occasion, it transpired that conflicting traffic was the priority. Turning to the cause, it was apparent that the PA28 pilot had not been concerned by the proximity of other aircraft during his flight and, given the proximity reported by the Vigilant pilot, the Board’s opinion was that he did not see the Vigilant. Given the proximity and this non-sighting, the Board felt that safety margins had been much reduced below normal. The Lakenheath APR was not required to provide TI, but the Board opined that he had sufficient Situational Awareness of the two aircraft that warranted timely TI; the Board considered that lack of timely TI was contributory to the cause. It was also noted that had either pilot obtained a Traffic or Deconfliction Service, this Airprox would probably not have occurred. The Board considered that a recommendation was warranted for Lakenheath to review their RT nomenclature and ATS provision.


Cause

: A non-sighting by the PA28 pilot of the Vigilant that he was overtaking.

Contributory Factor(s)

: Lack of timely TI from the Lakenheath controller.

Degree of Risk

: B.

ERC Score7

: 100

Recommendation(s)


: Lakenheath review their RT nomenclature and ATS provision.

1


Position: 51 40N 000 09E (1.6nm North of Stapleford)

Airspace: Stapleford ATZ (Class: G)


Type: C152 PA28R

Operator: Civ Trg Civ Club

Alt/FL: 1200ft 1400ft QNH (NR hPa) QNH (NR hPa)

Weather: NK VMC CAVOK

Visibility: >10km >10km


Few Hundred ft V NR V/NR H


300ft V/0nm H


THE C152 PILOT reports flying in the left-hand visual circuit to RW04 at Stapleford, with a student, at 90kts. After reaching 1200ft and turning on to the cross-wind leg he noticed another aircraft climbing-out. After manoeuvring his aircraft to check the position of the PA28R, he could see that it was behind him and was getting closer. Concerned that the other pilot may not be aware of his position, or the decreasing separation, the C152 pilot instructed his student to assist with lookout and, when they realised the PA28R was continuing to close on them, he flew an ‘evasive manoeuvre,’ descending to 900ft whilst making an RT broadcast to see if the PA28R pilot was visual with his Cessna; he did not hear a response. The C152 pilot continued to manoeuvre to keep the PA28R in sight and then saw it fly ‘a few hundred feet’ above him before hearing its pilot report clear of the circuit and changing frequency. THE PA28R PILOT reports flying a white and blue aircraft, with transponder Modes 3/A and C turned on. He took off from RW04 behind the C152, which he assessed to be in the visual circuit. He was flying to Oaksey Park, requiring a westerly departure, and realised that he would over-take the other aircraft on the cross-wind leg, so both he and his passenger maintained visual contact with the C152 throughout the occurrence. He reports heading around 270°, whilst climbing at 100kt to his cruising altitude of 1400ft, over-taking ‘behind’ the C152, and did not consider that, at any time, he ‘became too close to it’. THE STAPLEFORD AIR/GROUND OPERATOR was not able to report any details of the incident. Factual Background The London City weather 0850 was recorded as: METAR EGLC 100850Z 02009KT 350V090 9999 FEW042 20/12 Q1026 The Stanstead weather at 0850 was recorded as: METAR EGSS 100850Z 03010KT 9999 FEW021 19/13 Q1027


C152↑ 1200ft amsl

PA28R↑ 1400ft amsl

0909:26

600’

09:461000’

Stansted CTA 1500-2500ft amsl & TMZ Sfc-1500ft

1000’

800’

0910:02100ft V / 0.2nm H

CPA 0910:50300ft V / 0.2nm H

1000’

1100’1000’

1300’

NM

0 1 2

Stapleford ATZ

2


UKAB Secretariat At 0909:26 the C152 can be seen on the Stanstead radar, 1.2nm north-east of Stapleford, tracking north-east, indicating 1000ft amsl as the PA28R appears 0.4nm south-west of it indicating 600ft amsl. Both aircraft track north-east until 0909:47, when first the PA28R and then the C152 turn left; the C152 takes up a north-westerly track, indicating 1000ft amsl, and the PA28R takes a more northerly track, indicating 800ft amsl and turning slightly inside the C152’s turn. At 0910:02 the PA28R, heading northwards at 1000ft amsl indicated, passes 0.2nm behind the C152 which is tracking approximately 290°, indicating 1100ft amsl. At 0910:19 the aircraft are 0.3nm apart, both indicating 1100ft amsl. Shortly afterwards, the C152 continues on its track and the PA28R (now indicating 1200ft amsl) continues to turn left onto a more westerly track and again passes 0.2nm behind the C152 (now indicating a descent through 1100ft amsl). The PA28R rolls out 0.2nm behind the C152, on a similar track, indicating a steady climb through 1300ft amsl. At 0910:50 the aircraft returns briefly merge before the C152’s return disappears; at this point the PA28R is indicating 1300ft amsl and, before it’s return disappears, the C152 indicates 1100ft amsl. The C152 had right of way because it was being overtaken by the PA28R, which should have overtaken on the right of the C152.1 Furthermore, the PA28R pilot had the responsibility to ‘keep out of the way’ of the C152 until the aircraft were clear of each other.2 Finally, an aircraft which is obliged to give way to another aircraft is required to avoid passing over or under the other aircraft, or crossing ahead of it, unless passing well clear of it.3

Summary The C152 took off from RW04 at Stapleford and entered the left-hand visual circuit climbing to 1200ft. The PA28R took off from the same runway for a westerly departure, climbing to 1400ft. The crew of the PA28R maintained visual contact with the C152 whilst first passing from left to right, 0.2nm behind it, and then passing around 300ft above the C152. The C152 pilot, concerned by the proximity of the higher performance aircraft, descended to 900ft to avoid the PA28R.


Information available included reports from the pilots of both ac, transcripts of the relevant RT frequencies, radar photographs/video recordings, reports from the air traffic controllers involved and reports from the appropriate ATC and operating authorities. Board members noted that this Airprox occurred at a busy training airfield and that this, and the presence of the Stanstead CTA and TMZ to the north, could have constrained both pilots’ routings. Nonetheless, the Board members were clear that the PA28 pilot had the responsibility to keep well clear of the C152 whilst overtaking it, and should have avoided overtaking above it. Some Board members opined that it was possible that the PA28 pilot had believed that he had overtaken the C152 when their flight-paths had first crossed but, because the PA28 pilot had reported his heading as 270° at CPA, it was more likely that he had maintained visual contact with the C152 throughout and had not actually overtaken until the second crossing. Given that both pilots could see the other’s aircraft, and that the C152 pilot had also taken effective and timely avoiding action, the Board agreed that there was not a risk of collision and decided that the Degree of Risk was C. Nevertheless, the Board noted that the PA28 pilot was required, by the Rules of the Air, to keep well clear of the C152 whilst overtaking it. The measured separation was 300ft V and 0.2nm H; the GA pilot members felt that, whilst this could be considered sufficient separation in many other Class G airspace encounters, it

1 Rules of the Air 2007, Rule 11, para 1. 2 Rules of the Air 2007, Rule 11, para 2. 3 Rules of the Air 2007, Rule 8, para 4.

3

was too close to be deemed ‘keeping well clear’ during an overtaking manoeuvre. Consequently, the Board concluded that the cause of the Airprox was that the PA28 pilot flew close enough to cause the C152 pilot concern.


Cause

: PA28 pilot flew close enough to cause the C152 pilot concern.

Degree of Risk

: C

ERC Score4


: 2

1


Position: 5203N 00014W (2.7nm NE RAF Henlow)



Type: Vigilant T1 PA28


Alt/FL: 2500ft 2500ft QFE (1019hPa) QNH (NK)

Weather: VMC HAZE VMC CLBC



0ft V/0.5nm H Not Seen


NK V/0.2nm H

PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE VIGILANT PILOT reports conducting an instructional sortie, seated in the RH seat. The white and ‘day-glow’ orange aircraft had landing, navigation and strobe lights selected on, as was the SSR transponder with Mode A. The aircraft was not fitted with an ACAS. The pilot was operating under VFR in VMC without an ATS with Henlow A/G RTF selected. Approximately 3nm S of Biggleswade and 2nm to the E of Henlow, heading S at 60kt in level flight, he saw an aircraft approaching from the 12 o’clock position. He made a steep turn to the R, in order to avoid a collision; the PA 28 pilot did not appear to take any avoiding action. He noted that the haze made it difficult to see the other aircraft. He assessed the risk of collision as ‘High’. THE PA28 PILOT reports conducting a transit. The red and white aircraft had the SSR transponder selected on with Modes A, C and S; the lighting state was not reported. The aircraft was not fitted with an ACAS. Both the pilot and his passenger, also a PPL holder, were operating under VFR in VMC without an ATS, ‘listening to Luton’. He was transiting on a heading of 320°, in the level cruise at 110kt and altitude 2500ft , outside CAS and in ‘very adequate visibility’. Neither he nor his passenger were aware of an Airprox until contacted after the event and asked to complete an Airprox form. Factual Background The weather at Luton was recorded as follows:

METAR EGGW 170920Z VRB02KT 9000 NSC 24/15 Q1025 METAR EGGW 170950Z VRB03KT CAVOK 25/15 Q1025


PA282500ft alt

CPA 0935:58NK V/0.2nm HNM

0

1

2

3

Vigilant T135:46

35:34

35:22

35:10

0934:58

2


UKAB Secretariat Both pilots were equally responsible for collision avoidance1. From the geometry of the encounter, it was apparent that they were required to alter course to the right if there was a danger of collision2, which was the avoiding action the Vigilant pilot took. Neither pilot was in receipt of an ATS. The PA28 pilot did not see the Vigilant and did not recall being involved in an Airprox. HQ Air Command The Vigilant pilot saw and avoided the conflicting PA28 and correctly highlighted the point that the geometry was a significant factor in delaying his visual acquisition, both due to the lack of any lateral movement and the fact that the PA28 was almost head-on. The sighting range was reasonable in these circumstances. The Vigilant fleet often operate in areas where no radar services are available, or where a service is not compatible with the instructional nature of the majority of their sorties. The upcoming fitment of PowerFLARM3 to the fleet should provide advanced warning of the approach of other transponding ac, and highlight the location of conflicting FLARM-equipped ac.

Summary A Vigilant T1 and a PA28 flew into confliction at 0936 on 17th July 2013. The Vigilant pilot took avoiding action; the PA28 pilot did not see the Vigilant. PART B: SUMMARY OF THE BOARD'S DISCUSSIONS Information available included reports from the pilots of both ac and a radar video recording. The Board first considered the pilots’ actions. They were both operating in Class G airspace under VFR and without an ATS. The Vigilant pilot achieved collision avoidance by manoeuvring to the right when he saw the PA28. The PA28 pilot did not recall seeing the Vigilant, although Board members opined that it was ‘there to be seen’. Planning to route around glider sites was considered a valuable factor to mitigate against mid-air collision, but should also be coupled with added lookout for gliders, motor gliders and tugs, both on the ground and in the air. Members were of the opinion that the incident occurred at a position where both pilots could have availed themselves of the proven benefit of an ATS. The Board concluded that the cause of the Airprox was a non-sighting by the PA28 pilot but that effective, albeit late, action was taken by the Vigilant pilot and that safety margins had not been significantly reduced. PART C: ASSESSMENT OF CAUSE AND RISK Cause: A non-sighting by the PA28 pilot. Degree of Risk: C. ERC Score4: 4

1 Rules of the Air 2007 (as amended), Rule 8 (Avoiding aerial collisions). 2 Rules of the Air 2007 (as amended), Rule 10 (Approaching head-on). 3 PowerFLARM is a traffic warning system, developed from FLARM (Flight Alarm). In addition to other FLARM and PowerFLARM equipped aircraft, it can also detect and warn against aircraft fitted with SSR transponders with Mode C or S selected or emitting an ‘ADS-B out’ signal. 4 Although the Event Risk Classification (ERC) trial had been formally terminated for future development at the time of the Board, for data continuity and consistency purposes, Director UKAB and the UKAB Secretariat provided a shadow assessment of ERC.

1


Position: 5207N 00054W (5nm NE Silverstone)



Type: PA42 Nimbus 2C

Operator: Civ Comm Civ Pte

Alt/FL: 3000ft 3000ft NK (1021hPa) QNH (1024hPa)

Weather: VMC NK VMC CLBC

Visibility: >10km 20km


0ft V/50m H <100ft


NK V/<0.1nm H PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE PA42 PILOT reports conducting a transit flight, the majority of which he was aware was covered by a NOTAM for gliding activity. The white, blue and red ac had navigation, strobe lights and HISLs selected on, as was the SSR transponder with Modes A and C. The ac was not fitted with an ACAS. The pilot was operating under VFR in VMC and was not in receipt of an ATS. He concentrated on an effective lookout to mitigate the risk due to the increased glider activity, and had already seen and avoided several gliders. He noted that, although there was no cloud and that visibility was ‘good’, conditions were hazy with no horizon. Whilst in straight-and-level cruise, heading 065° at 220kt and 3000ft, he saw a glider just right of the nose, at an estimated range of 200m, head-on and co-altitude. He broke left immediately to avoid collision. He stated the glider pilot did not appear to manoeuvre. He assessed the risk of collision as ‘High’. THE NIMBUS PILOT reports conducting a competition flight1. The white and red ac was not fitted with external lighting or an SSR transponder but was fitted with FLARM2. The pilot was operating under VFR in VMC, without an ATS, and was listening out on the BGA RTF of 130.125MHz3, he thought. Whilst in ‘level cruise’, heading 235° at 60kt, he saw a white, low-wing, twin-engine ac just to the right of the nose, at an estimated range of less than 100ft and co-altitude, in a ‘well banked’ left turn. He stated that ‘all the avoiding action was taken by the twin’ and that if it had not been taken, they would have collided. He noted that, at the time, his lookout was compromised due to his concentrating on finding ‘signs of lift’. He assessed the risk of collision as ‘High’.

1 The competition ACN is reproduced at Annex A. 2 Flight Alarm (FLARM) is the name given to a low power, weight and cost electronic device designed to alert pilots to potential collision. It responds to other FLARM equipped aircraft with an effective range of 3-5km and is therefore optimised for low speed aircraft. 3 British Gliding Association (BGA) members are assigned 5 RT frequencies by the CAA with which to facilitate intra-glider and Aeronautical Ground Station communication. The frequency 130.125MHz has the promulgated primary use of ‘Training (lead and follow)’ and secondary uses of ‘Other cross-country location messages ‘ and ‘Local and other flying Competition start and finish lines’.

Diagram based on radarand GPS logger data

PA423100ft alt CPA 1513:41

NK V < 0.1nm H13:27

NM

0 1 2

Group of PSR onlytracking SW

SSR/PSR/GPS track merge

Nimbus GPS track

13:09

1512:51

Nimbus

2

Factual Background The Cranfield weather was recorded as follows:

METAR EGTC 131450Z 03006KT 350V070 9999 FEW049 29/15 Q1024 METAR EGTC 131550Z 02006KT 350V070 CAVOK 28/16 Q1024

A NOTAM was issued for the gliding competition, as follows:

(H2472/13 NOTAMN Q) EGTT/QWGLW/IV/M /W /000/100/5208N00151W010 A) EGTT B) 1307130402 C) 1307212014 D) SR-SS E) MAJOR GLIDING COMPETITION INCLUDING CROSS-COUNTRY RTE. INTENSE ACT WI 10NM RADIUS 520803N 0015103W (BIDFORD AD, WARWICKSHIRE). UP TO 30 GLIDERS AND 5 TUG ACFT MAY PARTICIPATE. GLIDERS WILL NORMALLY OPR BLW THE INVERSION LVL OR BTN THE TOPS OF ANY CU CLOUDS AND 500FT AGL. RTF 129.975MHZ. FOR INFO ON DAILY TASK RTES CTC GLIDER COMP CTL TEL 01789 778807 OR 07803 299773 OR VIEW WWW.BGALADDER.CO.UK/SHOWTASK.ASP FOR BIDFORD. 13-07-0095/AS3. F) SFC G) FL100)


UKAB Secretariat Both pilots were operating under VFR in VMC. They had equal responsibility for collision avoidance4 and, as they were approaching head-on, were required to alter their course to the right if there was a danger of collision5. Neither pilot had right of way6 and neither was in receipt of an ATS.

Summary A PA42 and a Nimbus 2C came into conflict at 1514 on 17th July 2013, at a position 5nm NE of Silverstone. The PA42 pilot took avoiding action by turning left; the Nimbus pilot saw the PA42 too late to take avoiding action. PART B: SUMMARY OF THE BOARD'S DISCUSSIONS Information available included reports from the pilots of both ac, radar video recordings and a GPS logger file. The Board first considered the pilots’ actions. Both pilots were equally responsible for collision avoidance and the PA42 pilot had reported a heightened awareness of increased gliding activity, with a commensurate increase in his lookout activity. The Nimbus pilot reported that his lookout may have been compromised by his increased concentration on finding ‘signs of lift’. In the event, the PA 42 pilot saw the glider at what the Board considered to be near to his last opportunity to achieve effective collision avoidance. He broke left and the glider pilot, with less rapid manoeuvering capability (and who the Board opined had seen the PA42 a few seconds later), stated that a collision would have occurred otherwise. The Board considered that the PA42 pilot’s avoiding actions were entirely appropriate and, not having had the time or separation to turn to the right iaw Rule 10 (Approaching head-on), he fully discharged his collision avoidance responsibility under Rule 8 (Avoiding aerial collisions). Pilot members opined that powered-aircraft pilots could mitigate glider collision risk vertically by either transiting above an inversion layer or cloud base or by staying low, or horizontally 4 Rules of the Air 2007 (as amended), Rule 8 (Avoiding aerial collisions). 5 ibid., Rule 10 (Approaching head-on). 6 ibid., Rule 9 (Converging) states that ‘flying machines shall give way to airships, gliders and balloons’, however, Rule 9 is subject to Rule 10, in which a right of way or requirement to give way is not asserted.

3

by applying as wide a berth as possible from known gliding activities. However, it was acknowledged that these strategies could create problems of their own due to airspace constraints or confliction with low-flying military traffic for example: any plan very much depended on the specific route and conditions of the day but the point to be made was that both powered-aircraft and glider pilots should actively consider all mitigations possible, especially when planning to operate through or near to NOTAM’d activities. . The Board also considered the effectiveness of notification procedures associated with glider competitions and opined that there was potential for improvement. The current NOTAM information did not directly include intended competition task routes or general routeing areas; it relied on other affected airspace users, who could be up to hundreds of kilometres from the NOTAM glider site, taking further action to check for more comprehensive routeing information. Recognising the late stage at which daily tasks might be decided (sometimes only a few hours before launch), the Board opined that, nevertheless, more effective and timely promulgation of tasks and routes was required such that affected airspace users could easily acquire up-to-date and pertinent information without having to check through a number of diverse sources of information (which might not be readily available depending on the facilities at the departure airfield or strip). The Board resolved to recommend to the BGA Competition Committee that it review the content of glider competition NOTAMs and promulgation of daily task notification, such that affected airspace users could more readily obtain information on glider flights that could affect their operations. In this respect, it was noted that a number of electronic planning aids were available that could be used by the aviation community to provide more dynamic awareness of planned tasks. The Board considered that the PA42 pilot had seen the Nimbus glider at or near his last opportunity to effect collision avoidance and that there was a high probability that the aircraft would have collided had he not done so. His break manoeuvre resolved the confliction, thereby improving matters, but the Board opined that, in this instance, safety margins had been much reduced below the normal. PART C: ASSESSMENT OF CAUSE AND RISK Cause: A conflict of flight-paths resolved by the PA42 pilot. Degree of Risk: B. ERC Score7: 20 Recommendation: The BGA Competition Committee reviews content of glider competition

NOTAMs and promulgation of daily task notification.


Annex A to 2013079

1

Annex A to 2013079

2

Annex A to 2013079

3

1

AIRPROX REPORT No 2013080 Date/Time: 14 Jul 2013 0846Z (Sunday)

Position: 5134N 00016W (2.5nm NE of Damyns Hall)

Airspace: London FIR (Class: G)


Type: MD902 C172

Operator: Civ Comm Civ Pte

Alt/FL: 1600ft 1600ft QNH (1024hPa) NK (NR hPa)

Weather: VMC CLBC VMC CLBC



NR V/200m H 0ft V/NR H


0ft V/0.1nm H PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE MD902 PILOT reports flying a blue and yellow helicopter straight and level, heading 200°, at 120kts and returning to Redhill, having been on task near Chelmsford; he reported his workload as low. Landing lights, HISLs, strobe lights and navigation lights were all on, and the transponder was squawking Modes 3/A and C. The crew were receiving a Basic Service from Farnborough LARS North. When the helicopter was near Brentwood, the crew member in the front left-hand seat saw the C172 in his left, 11 o’clock position, around 200m away at the same level. He immediately alerted the pilot who turned the helicopter about 60° to the right to maximise separation. The pilot perceived that the C172 was already turning right to avoid them and estimated the minimum horizontal separation as 200m. The MD902 pilot recalls that the Farnborough LARS frequency had a high level of traffic on it and so he elected to report the Airprox by telephone after landing. THE C172 PILOT reports heading 010° at 100kts, with the tail beacon, strobe lights and navigation lights turned on, and receiving a Basic Service from Farnborough LARS North. He had originally been heading from Biggin Hill to Duxford but Farnborough reported that the weather at Duxford was poor, and so he elected to divert to North Weald. He reports that he did not see the helicopter until ‘very late’ and thought this may have been partly due to the reduced visibility and the distraction caused by looking for the North Weald approach plate. Although he did not take any avoiding action, he felt he could have done ‘if it had been necessary.’ THE FARNBOROUGH LARS CONTROLLER reports the sector was ‘very busy’ due to an airshow at Duxford and poor weather in the area. When he took over the position the MD902 was ‘on task’ in the Brentwood area, under a Basic Service, and he recalls acknowledging when the pilot reported overhead Brentwood at 1000ft. At around 0840, the pilot reported that his tasking was complete and that he was heading back towards Redhill; at 0848 the pilot reported changing frequency to Heathrow Special. At no point did the LARS controller observe another aircraft in close proximity to the MD902. Factual Background The weather observed at Cambridge at 0820 and 0850 was:

METAR EGSC 140820Z VRB03KT 4800 HZ BKN007 18/15 Q1025 METAR EGSC 140850Z VRB02KT 4500 HZ BKN007 18/15 Q1025

Diagram based on radar data MD9021600ft alt

C1721600ft alt

CPA 0846:240ft V/< 0.1nm H

46:10

45:5845:46

45:34

NM

0 1

2

The weather observed at Stanstead at 0820 was:

METAR EGSS 140820Z 33004KT 260V030 6000 SCT011 20/16 Q1025 The weather observed at London City at 0850 was:

METAR EGLC 140850Z AUTO VRB03KT 9999NDV NCD 23/15 Q1024 The weather observed at Southend at 0850 was:

METAR EGMC 140850Z 12005KT 080V180 CAVOK 23/16 Q1024 Analysis and Investigation

CAA ATSI had access to Farnborough RT and area radar recordings, together with the written reports from the Farnborough controller and both pilots. At the time of the AIRPROX, poor weather was being experienced around the London TMA resulting in a number of aircraft diverting, as they were unable to reach their final destinations. The unofficial weather at North Weald was reported as 5000 metres in haze and FEW at 1800ft.

The MD902 departed Redhill and contacted Farnborough LARS North at 0828:00, in the vicinity of Brentwood, reporting VFR at 1800ft on 1024hPa, and requesting a Basic Service. The Farnborough LARS North controller agreed a Basic Service confirming the London QNH as 1024hPa. The MD902 continued heading north-east to operate in the Chelmsford area. At 0838:25 the C172 contacted Farnborough LARS North, routeing VFR from Biggin Hill to

Duxford, reporting overhead Swanley at 2000ft and requesting a Basic Service. The controller agreed a Basic Service and instructed the C172 to squawk 5032, confirming the London QNH as 1024hPa. The controller informed the C172 pilot, “(C172)c/s just be aware the cloud-base at Duxford is currently around six hundred feet, I haven’t had any aircraft that have got in there recently they’re having to hold er to try and wait for the weather”. The C172 pilot replied, “(C172)c/s copy that”.

At 0841:40 the MD902 pilot reported, “er Farnborough er (MD902)c/s now complete er

Chelmsford routeing back to er Redhill er fifteen hundred feet one zero two four advise going en- route”. The controller replied, “(MD902)c/s that’s all copied report crossing the Thames”. This was acknowledged by the MD902 pilot.

At 0844:46 radar showed the MD902 tracking south-westerly at an altitude of 1700ft. The C172

was in the MD902’s half-past ten at a range of 5.4nm, tracking north, on the east side of the M25, at 1600ft. The two aircraft continued to converge.

At 0845:00 the C172 pilot reported, “Yeah er Farnborough north er (C172)c/s in view of the er

weather at Duxford er I think we’ll er divert and er go to erm land at er North Weald er are you able to give me their weather”. The Farnborough controller responded, “Roger I’ll see if I can get an unofficial observation for you”.

The ATSU indicated that there was no direct dial facility for North Weald and the controller

needed to look up at the information display overhead the radar display in order to obtain the BT telephone number. The controller then became involved in a lengthy conversation with North Weald.

Meanwhile the two aircraft continued to converge and at 0846:15 the range between them was

0.5nm with both aircraft indicating an altitude of 1600ft. At 0846:22 the range between the aircraft had reduced to 0.1nm as shown in Figure 1 below.

3

Figure 1 - Swanwick MRT at 0846:22

The CPA occurred between radar sweeps at 0846:24, when the estimated range between the two

aircraft was 0.03nm (182ft), with the C172 tracking to pass behind the MD902 (see Figure 2). At 0826:26 the two aircraft, at a range of 0.1nm, had passed and were diverging at an altitude of 1600ft as shown in Figure 2 below.

Figure 2 - Swanwick MRT at 0846:26

The MD902 pilot’s written report indicated that, as a result of sighting the C172 at a range of

approximately 200m, he turned right by 60° to increase separation. The traffic loading on the RT frequency was such that he was unable to report the Airprox at the time.

The written report from the C172 pilot indicated that the MD902 was not sighted until very late; he

assessed that cockpit distractions, such as looking for the North Weald approach plate and poor visibility, may have contributed to the late sighting. He also reported that he could have taken avoiding action had it been necessary.

4

Meanwhile, at 0847:10 the following RTF exchanged occurred: ATC: “And er (C172)c/s North Weald weather when ready to copy” C172: “Yeah go ahead”

ATC: “(C172)c/s it’s er the visibility five thousand metres in haze, their cloud few at one thousand eight hundred”

C172:“Yeah five thousand metres in haze and er few at one thousand eight

hundred feet, in which case we’ll land at North Weald (C172)c/s” ATC: “(C172)c/s roger that’s copied I have pre-noted them so they are expecting you” C172: “(C172)c/s copied thanks” At 0848:33 the MD902 reported, “er Farnborough (MD902)c/s just approaching the Thames, I’ll go

en-route thanks”. The controller responded, “(MD902)c/s roger goodbye”. At 0849:01 the controller cautioned the C172 that Stapleford ATZ was active and the pilot

responded that he almost had North Weald in sight; shortly afterwards the pilot changed squawk to 7000 and transferred to North Weald on frequency 123.52MHz.

The written report from the Farnborough controller indicated that he had not observed any other

aircraft in close proximity to the MD902. Neither the MD902 pilot, nor the C172 pilot, mentioned sighting the other aircraft whilst on the frequency. The MD902 pilot subsequently telephoned Farnborough ATSU to report the Airprox.

The ATSU written report indicated that pilots will often request weather information from

Farnborough and that this can often be lengthy and time consuming. Farnborough controllers will either ring the airfield concerned or may ask an available assistant to do this. There was an assistant available but it was unknown what tasks they were involved with at the time.

ATSI Analysis: The two aircraft were in receipt of a Basic Service from Farnborough LARS North. ‘A Basic Service is an ATS provided for the purpose of giving advice and information useful for the

safe and efficient conduct of flights. This may include weather information, changes of serviceability of facilities, conditions at aerodromes, general airspace activity information, and any other information likely to affect safety. The avoidance of other traffic is solely the pilot’s responsibility.

Basic Service relies on the pilot avoiding other traffic, unaided by controllers/FISOs. It is essential

that a pilot receiving this service remains alert to the fact that, unlike a Traffic Service and a Deconfliction Service, the provider of a Basic Service is not required to monitor the flight1

.’

The controller was busy and RT loading was reported as high. It is likely that the Airprox occurred as the controller’s attention was focused on obtaining the telephone number and weather for North Weald.

The C172 pilot was very likely distracted by the diversion, weather and looking for an approach

plate and, when he sighted the MD902, considered that avoiding action was not necessary. The MD902 pilot sighted the C172 and turned right to avoid it, believing that the C172 had also

turned right. 1 CAP774, Chapter 2, Page1, Paragraph 1

5

Within Class G airspace, regardless of the service being provided, pilots are ultimately

responsible for collision avoidance. A pilot who considers that he requires a regular flow of specific traffic information must request a Traffic Service. The controller was not required to monitor the two aircraft and had not observed them in close proximity. The controller was therefore unable to provide any warning.

UKAB Secretariat Both aircraft were being flown in Class G airspace and both pilots had the responsibility to ensure

that their aircraft did not collide or come in to such proximity to each other as to create a danger of collision.2

The aircraft were converging, and the C172 had the MD902 on its right; consequently the C172 should have given way to the MD902.3

Summary The Airprox occurred in class G airspace between an MD902 and a C172. Both pilots were receiving a Basic Service from Farnborough LARS North but the controller did not observe the two aircraft in proximity and was not able to provide any warning. The aircraft were both flying at 1600ft amsl and were converging with the MD902 on the C172’s right. Both pilots were operating VFR in VMC, however the weather at the C172’s destination had deteriorated and the pilot had elected to divert to North Weald and reports that his work-load was increased as he divided his attention between looking-out and finding the North Weald approach plate. The C172’s pilot reports that he saw the MD902 ‘very late’ and did not take any avoiding action. A member of the MD902’s crew saw the C172 around 200m away and the pilot made a right avoiding action turn resulting in a CPA of 0ft vertically and <0.1nm horizontally. PART B: SUMMARY OF THE BOARD'S DISCUSSIONS Information available included reports from the pilots of both ac and the Farnborough LARS controller, transcripts of the relevant RT frequencies, radar video recordings, and reports from the appropriate ATC and operating authorities. The helicopter and the GA pilot members lead the discussion and noted that both aircraft were being flown in a perfectly normal manner, with the pilots going about their business under a Basic Service. There was some discussion about the Air Traffic Service they had elected to adopt as some members felt that, given the haze and deteriorating weather observations, a Traffic Service would have been more appropriate. Whilst it was agreed that a Traffic Service may have helped the pilots to see the other aircraft earlier, it was also noted that the pilots had reported the visibility as 8km and 10km at the time of the Airprox and so they had more than adequate conditions to rely on visual lookout. Board members then discussed the role of the Farnborough controller and wondered if, despite being under a Basic Service, Traffic Information could have been passed. An advisor informed the Board that Farnborough LARS is extremely busy at weekends, as was clearly the case on this particular Sunday, and it would have been unlikely that the controller would have had the capacity to offer more that the terms of the Basic Service required. If the pilots had requested a Traffic Service the controller could have assessed his workload and priorities to try to provide the services requested but, given the high traffic loading, he may not have been able to offer more than a Basic Service anyway. It was agreed that given the traffic densities on the day it was not reasonable to expect the Farnborough LARS controller to have spotted the confliction, and so Traffic Information should not have been expected by default.

2 Rules of the Air 2007, Rule 8, Avoiding aerial collisions 3 Rules of the Air 2007, Rule 9, Converging

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The MD902 was being operated on behalf of a police force and the Board was surprised that it was not fitted with a TCAS; although not a panacea for all situations, in this circumstance of meeting another squawking aircraft TCAS would have been able to detect, provide indications, and offer flight vectors to resolve this confliction. When discussing the risk associated with this Airprox the Board noted the late sighting by both pilots despite their reportedly good weather conditions. Although the C172 pilot reported that he could have taken avoiding action ‘if it had been necessary’, the Board felt that this was probably a misperception; at a CPA of less than 0.1nm, members felt that, at that distance, some sort of avoidance manoeuvre would have been warranted. Notwithstanding the C172 pilot’s statement and the fact that the MD902 pilot’s actual avoiding action had been effective, the Board considered that this had been a close encounter where normal safety margins had been much reduced; they graded the Degree of Risk as B. PART C: ASSESSMENT OF CAUSE AND RISK Cause: Late sighting by both pilots, resolved by the MD902 pilot. Degree of Risk: B ERC Score4

: 20

Recommendation: The National Police Air Service reviews the equipping and employment of TCAS (and P-FLARM) in Police Helicopters.


1


Position: 5710N 00341W (6nm E Aviemore)

Airspace: LFA 14 (Class: G)


Type: Sea King Tornado GR4

Operator: HQ Air (Ops) HQ Air (Ops)

Alt/FL: 150ft 300ft agl agl

Weather: VMC VMC CLBC



100ft V/0m H Not Seen


NK PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE SEA KING PILOT reports undertaking mountain flying training in the Cairngorms. The yellow helicopter had the upper strobe light selected on and to red, the lower strobe off, pilot’s landing lamp on, rear spot light on and pointing backwards, and navigation lights on. The SSR transponder was selected on with Modes A and C. The aircraft was not fitted with an ACAS. The Sea King pilot was operating under VFR in VMC without an ATS. It was noted prior to flight that there was an increased risk from extensive fast-jet traffic associated with a NOTAM’d local military exercise but when their low-level booking was made the route showed no conflictions in CADS1. After approximately 1hr of mountain flying training, the Sea King pilot elected to land at Glenmore Lodge2 to pick up some role equipment which had been left on a previous operation. The recovery and pre-landing checks (including strobes to red, although both rear and forward spot lights were on) were completed and the base was contacted by FM radio to establish whether the landing site was available. Low-level common frequency was being monitored but no calls were made. The pilot was in a descending right hand turn, passing through a heading of 070° at 60kt and approaching a position of long finals about ¼nm from the site, when the crew noticed both the jet noise and the shadow of an aircraft as it flew directly overhead, about 100ft above. The other aircraft was identified as a Tornado but it had not been seen prior to CPA. Expecting the possibility of a second aircraft, the strobes were selected back to white and a call was made on the low-level common RTF to which the Tornado pilot replied confirming that he had indeed just passed Glenmore and that he had not seen the Sea King. He assessed the risk of collision as ‘Low’. THE TORNADO PILOT reports conducting a passenger flight, operating on detachment from home base. The grey camouflaged aircraft had navigation, obstruction and strobe lights selected on, as was the SSR transponder with Modes A and C. The aircraft was not fitted with an ACAS. The pilot was operating under VFR in VMC without an ATS and was listening out on the low-level common frequency. After 15min of general handling, the pilot entered low-level 10nm South of Inverness airport and flew a pre-planned low level route in an anti-clockwise direction down Loch Ness to Fort

1 Centralised Aviation Data Service (CADS) is a secure, and collaborative, advisory web based flight planning service that reduces the risk of collision with other aircraft and physical hazards such as overhead wires in uncontrolled airspace. 2 Glenmore Lodge is the Scottish National Outdoor Training Centre, located 6nm East of Aviemore, in the Cairngorms National Park.

Diagram based on pilot reports

Tornado

CPA 1524

Sea King

2

William and then East towards the Cairngorms. As he entered low-level, he made a radio call on the low-level common frequency detailing this route but heard no reply. Shortly after flying past Glenmore Lodge, heading 090° at 400kt, he climbed for a medium-level transit back to base. On passing 4000ft the pilot heard a transmission on the low-level common RTF from a Sea King pilot, calling to a Tornado aircraft in the vicinity of the Cairngorms. The Tornado pilot replied and ascertained that he had just over-flown the helicopter in the vicinity of Glenmore Lodge. Neither the pilot nor the passenger saw the helicopter at any stage and thus were unable to assess the probability of collision. He noted that the weather was excellent, with no cloud and 30nm visibility. Factual Background The Inverness weather was recorded as follows:

METAR EGPE 191520Z 03010KT 9999 FEW040 22/14 Q1028 Analysis and Investigation

UKAB Secretariat Both pilots were entitled airspace users in the military low-flying system, correctly booked in and authorised to perform their tasks. They were equally responsible for collision avoidance3 and the Sea King pilot had right of way4. Glenmore Lodge is positioned at the Eastern end of a West-East orientated geological basin and, from the Tornado pilot’s approach path, the Sea King would have been manoeuvering against a background of trees, fields and terrain. The Sea King pilot was in a descending right hand turn, away from the approaching Tornado, and his attention was focused on the landing area. Occurrence Investigation The Sea King crew attended a SAR shift hand over brief, which included MET brief, NOTAMs, aircraft serviceability and any other issues. All crew were sufficiently rested and within crew rest time for the duration of the shift. Following the brief the crew decided to carry out a routine training flight to include a test of a recently repaired Rad Alt, mountain flight training and pick up of First Aid equipment from Glenmore Lodge in the Cairngorms. The planned take off time was 1400L. This time was selected to take advantage of reduced low flying activity from RAF Lossiemouth in the local airspace. Approx 45min prior to take off, the crew planned the sortie including an update of the MET and NOTAMs. As part of this planning process, the Ops Assistant input the sortie details into the CADS. As part of the out brief a check of CADS was carried out indicating there was no other planned military air traffic in the operating area. The actual departure time was 1500L. This was due to a visit from other personnel. The Ops Assistant adjusted CADS to reflect this timing change. After successfully testing the Rad Alt over the sea, the Sea King pilot proceeded to the Cairngorm mountain range to conduct mountain flying. On route to the Cairngorm range, he tuned the radio to the Low Level Common (LLC) frequency. They monitored the frequency throughout their time at low level over land, no broadcast was made to announce their position or intentions. On completion of the mountain flying, the Sea King pilot manoeuvred from a highpoint near Cairngorm mountain towards the Glenmore Lodge in the base of the valley. During this manoeuvre, the aircraft was flown at approx 100-150ft agl, as the crew were aware of the fast jet low flying limit of not below 250ft. This is a standard practice for rotary assets to give some separation from fast jet traffic.

3 Rules of the Air 2007 (as amended), Rule 8 (Avoiding aerial collisions) 4 ibid., Rule 11 (Overtaking)

3

After confirming by FM radio with Glenmore Lodge that the landing site was available, the Sea King pilot began an approach to land. Recovery and pre-landing checks were carried out. He was in a descending right hand turn, about ¼nm south of the lodge when the crew became aware of a fast jet passing overhead. The first indication was jet noise followed by a shadow passing over the aircraft. Only one of the rear-crew recalled seeing the other aircraft directly overhead and estimated it passed overhead at a distance of 100ft, but he did not have sufficient time to warn the other crew. The Sea King pilot made a transmission on LLC with his current position, mentioning that a fast jet had just passed overhead. The Tornado pilot replied, confirming that he had just passed Glenmore Lodge. The Tornado squadron was deployed to RAF Lossiemouth to take part in a large exercise, where the Squadron were operating from the ‘Northern HAS site’. The Tornado pilot planned 2 singleton passenger sorties on Thursday 18 July to be flown on the morning of Friday 19 July. The original plan was to carry out 2 consecutive sorties with an engine running change5, with both sorties using the same plan. The standard passenger flight paperwork was completed with correct authorisation for the flights. This included authorisation to carry out up to 15min of low-level flying. The Tornado pilot reported for duty on 19 July, being well rested and within crew rest hours, where he met and briefed both passengers. The pilot received a standard pre-flight brief, including MET conditions, airfield and aircraft serviceability. The final planning aspects of the sortie were completed, including low-level booking, warn-out and a check of warnings/NOTAMs for the period of each sortie. Both routes were input to CADS as separate sorties by the Ops staff. On this detachment the Squadron Ops staff travelled from the Pilot briefing facility on the Northern HAS site to a permanently based Squadron Ops to utilise a computer dedicated for CADS use; approximately 5 minutes walk. The Tornado pilot received an out-brief prior to flight and carried out the first sortie as planned, landing with sufficient fuel to carry out the second sortie without refuelling. On seeing-in the ac, the line crew noticed a minor unserviceability, resulting in a delay to the second sortie. The Tornado pilot crewed out of the aircraft and completed the sortie with an in-brief and post sortie paperwork. He decided to fly the second sortie at 1530L after the exercise traffic had landed. The original plan was used and the Tornado pilot rechecked MET, NOTAMs and warnings. The warn-out/low level bookings were amended to reflect the new takeoff time. The timings on CADS were not amended. The pilot received a standard out-brief prior to crewing in. This did not include a fly through on CADS to check for any deconfliction issues. The Tornado pilot took off at 1530L from RAF Lossiemouth and routed towards Tain range, to identify the various targets. On completion of the range reconnaissance, they proceeded south towards the Nairn gap. The pilot contacted Inverness RAD to pass his intentions and agreed a Traffic Service as he passed the airfield. Once south of Inverness airfield, he changed from Inverness RAD to the LLC frequency and immediately made a transmission to broadcast his position and intentions. He heard no response and flew the route as planned. Whilst flying, the Tornado pilot selected thermal heat cues to be displayed in the HUD. As only 15min low-level flying was planned, no further calls on LLC were made. The Tornado pilot entered the Cairngorm area and transited from south to north. The route took the aircraft over the top of the Cairngorm Mountains and into the valley to the south of Glenmore Lodge. Whilst entering the valley, the pilot manoeuvred the aircraft into a right hand turn with the right wing down, enabling him to look into the valley ahead. He flew past Glenmore Lodge, lining the aircraft up to pass through the valley 1nm to the north-east (see Airprox diagram). Shortly after passing Glenmore Lodge, the Tornado pilot heard the transmission from the Sea King pilot on LLC. The Tornado pilot assessed that he had been in proximity to the Sea King and replied on LLC, confirming he had just passed Glenmore Lodge. He confirmed that he had not seen the Sea King and completed the sortie with no further issues. The Tornado aircraft video tape did not record any flight data.

5 One engine is kept running after landing, maintaining power to the aircraft systems, whilst the returning passenger gets out and the next passenger is strapped in.

4

CADS was not updated to reflect the new timings of the second Tornado sortie, therefore any other CADS user would not have been made aware of deconfliction issues. At home base, the Squadron used stand alone computers in preference to DII terminals as DII terminals were deemed too slow and unreliable. Whilst on detachment at RAF Lossiemouth, no stand alone computer was available. The Squadron Ops procedure for CADS input whilst on this detachment was to walk across to an adjacent RAF Lossiemouth based Squadron and input the data on their dedicated CADS computer. The time to travel to the RAF Lossiemouth based Squadron from the detached Squadron location was approximately 5min walk. This also meant that no CADS flythrough was carried out at the out-brief as the designated CADS computer was not co-located at the out-brief desk. The out-brief did not specifically mention a check of CADS. The only mention was a generic ‘deconfliction’ in the out-brief check list. A check of CADS was not a mandated requirement at the time. No transmission was made on the LLC frequency by the Sea King pilot to broadcast their position and intentions. This was not a mandated requirement for the Sea King pilot.

Comments

HQ Air Command Whilst this incident could perhaps be viewed as a normal operating hazard, the lack of an accurate take-off time on CADS resulted in the sortie being flown without the best available situational awareness. This event occurred immediately prior to specific Defence-wide guidance on the use of CADS, so its use was not mandated at the time. It is nevertheless worthy of note that CADS was available, in-use and would have identified the conflict to the Tornado captain and authorizer, had it been updated with the delayed take-off time.

Since this event, CADS has become a mandatory element of sortie planning and authorization and depicts the planned tracks of approximately 120 sorties per day. The use of CADS has not reduced the requirement for solid sensor-management and thorough look-out during the sortie but has created the facility for awareness of potential military conflictions and subsequent mitigation. CADS continues to be rolled-out and will include other organisations, including air assets of HM Coastguard and the Police Force. RAF Flight Safety has provided LF Ops with a form of words to go into the LF Handbook, suggesting when calls on the LF Common frequency might be appropriate.

Summary A Tornado GR4 and a Sea King helicopter flew into confliction near Glenmore Lodge at 1524 on 19th July 2013. Both pilots were operating under VFR in the military low-flying system and were at low level. The Tornado pilot did not see the other aircraft. PART B: SUMMARY OF THE BOARD'S DISCUSSIONS Information available included reports from the pilots of both ac and reports from the appropriate operating authorities. Board members first considered the pilots’ actions during the flights. The Sea King crew were conducting a routine sortie for which the pilot had taken mitigating action against low-level fast-jet traffic by listening out on LLC (in the hope of gaining extra SA), and by consciously planning to remain not above 150ft agl (thereby generating a degree of height deconfliction from fast-jet traffic which was required to remain not below 250ft agl). The Board commented that, given he was about to conduct the focused task of landing at Glenmore Lodge where his attention would undoubtedly be on positioning and carrying out the landing manoeuvre rather than wider look-out, the Sea King pilot

5

might usefully have made a radio call to that effect in order to warn other low-level users. For his part, the Tornado pilot had used LLC on entering low-level, iaw SOP, but was geographically separated from the Sea King at the time and his transmission was therefore not heard by the Sea King pilot probably because of terrain masking. The Board felt that the key to this incident lay in the planning phase of the sortie and, in particular, the use of CADS. The delayed Tornado take-off time for the second passenger sortie had not been entered into the CADS system, and the Tornado pilot had not checked CADS for potential conflictions during his out-brief, which, at the time, was not a mandated action. The Military Pilot member informed the Board that CADS operation had been in its infancy at the time, and that subsequent development had resulted in SOPs for its use that could have prevented this occurrence. Notwithstanding, it was noted that CADS could only provide deconfliction between planned routes, and that military aircraft very frequently flew off-route for operational training reasons, thereby reducing the effectiveness of CADS deconfliction advice. The Board were informed that the tool was therefore used purely for conflict awareness, highlighting areas and times where there was potential for confliction to occur, and that ‘see and avoid’ remained the primary means of deconfliction at low-level. The Board were also informed that deconfliction would be further enhanced with the planned introduction of an ACAS to the Tornado fleet, which would have assisted in this occurrence by providing an electronic warning to the Tornado pilot of the Sea King’s presence. Given that the Tornado pilot did not see the Sea King during what was effectively an overtaking manoeuvre, the Board were unanimous in their assessment of the cause. However, members were divided over the degree of risk. All agreed that the incident was risk bearing, but some were of the opinion that chance had played a major part in events and that nothing more could have been done to improve matters (Category A). After considerable discussion there was a majority opinion that the height deconfliction achieved due to the pilots remaining respectively below 150ft agl (Sea King) and above 250ft agl (Tornado) had provided an element of separation, and effectively avoiding action, of its own even though the pilots had not been aware of the other’s aircraft. Nevertheless, it was decided, by a majority, that safety margins had been reduced much below the normal (Category B). PART C: ASSESSMENT OF CAUSE AND RISK Cause: A non-sighting by the GR4 pilot. Degree of Risk: B. ERC Score6: 101


1


Position: 5126N 00058W (19.5nm W LHR)

Airspace: Lon UIR (Class: C)


Type: A320 Unknown

Operator: CAT NK

Alt/FL: FL340 NK

Weather: NK NK

Visibility: NK NK


NK NK


NK

PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE A320 PILOT reports transiting in level cruise at FL340, just to the west of Heathrow. The First Officer (FO) in the RH seat, was looking down at the PLOG1. The Captain, in the LH seat, looked to the West out of the flight deck ‘Direct Vision’2 window. As he turned to look ahead, he perceived an object travelling towards them, at what appeared to be the same level, slightly above the flight deck windscreen. Having very little time to focus, he was under the apprehension that they were on a collision course with no time to react. His immediate reaction was to duck to the right and reach over to alert the FO; there was no time to talk to alert him. The FO turned and looked at him, thinking something was wrong with the aircraft. The Captain was fully expecting to experience some kind of impact with a conflicting aircraft. His first words to the FO were, “did you see that”, who replied, “see what”. The Captain perceived an object pass within a few feet above the aircraft. It could best be described as cigar/rugby ball like in shape, bright silver, and metallic like in construction. His first reaction after gathering his thoughts, was to interrogate the TCAS for returns within the area; none were seen. He then asked ATC for information on any aircraft in the vicinity, again there were no known aircraft in the area at the time and no other primary or secondary returns. He explained the situation to ATC and the crew both decided they would file an Airprox. Upon arriving at the destination, the Captain spoke extensively by phone with the ATC watch manager for that sector. The UK Airprox Board Secretariat was unable to trace the other aircraft. Factual Background At 1835 on 19 Jul 2013 at the position of CPA, the sun was at a bearing of 278° and elevation 21° at ground level3. This equates to an elevation of about 24° at FL340.

1 An abbreviation for Progress or Pilot’s Log. The PLOG is a tabular record which includes information such as planned track, heading, altitude, ETA and fuel state for each leg of the journey. Information such as actual track, heading, altitude, ETA and fuel state is completed as the flight progresses and is used to assess the safe progress of the flight. 2 The Direct Vision (DV) window, also known as the Direct Ventilation window, is a part of the windscreen that can be opened should direct vision be required, e.g. in the event of windscreen obscuration the pilot can open the DV window and look ‘directly’ outside, rather than attempt to judge a landing through the obscured windscreen. 3 As a guide, with a hand held at arm’s length, back of the hand facing you and fingers spread as wide as possible, the span from little finger to thumb subtends an angle of 20°-25°.

Diagram based on radar dataand pilot report

A320FL340

CPA 1835

2


CAA ATSI

The incident was reported to have occurred at approximately 1835, 19.5nm to the West of London Heathrow at FL340. The A320 pilot was operating under IFR in receipt of a Radar Control Service from London Control. CAA ATSI had access to area radar recording, together with the written report from the A320 pilot and the NATS Ltd investigation report.

The estimated viewing aspect through the DV window is shown at Figure 1 below.

Figure 1: LH DV window Viewing Aspect

At the time of the reported occurrence (1835:22) the radar recording was filtered to show aircraft operating within the level band FL320 and FL390 along with unknown primary contacts, these have been circled red in Figure 2 below.

Figure 2: Swanwick MRT at 1835:22

An unknown primary contact was recorded in A320’s 10 o’clock at a range of 2.2nm. This contact first appeared on the radar at 1828:53, in the vicinity of the village of Eling, approximately 30nm West of Heathrow. The unknown contact routed West and landed at White Waltham at 1846. This was identified as being a Tiger Moth aircraft which was operating at low-level and was eliminated from the investigation.

3

Three other aircraft are shown: a B747, 38.2nm West of the A320 at FL370 tracking east-southeast; a B737, 23.4nm northwest of the A320 at FL358 tracking south-southeast and another B737, 28.2nm ahead of the A320 at the same level on a similar routeing. The NATS Ltd AIS pre-flight bulletin, nav-warning for the London FIR, contained three NOTAMS which promulgated the release of Meteorological and Radiosonde balloons (with unlimited upper levels). The sponsors of each were contacted and it was confirmed that no balloons were released from the specified sites on the incident date. A NATS Ltd investigation was not able to verify the origin, level or size of the object reported by the A320 pilot. The Military Radar Analysis Cell (RAC) where unable to trace the reported object.

There were no radar traffic returns within the immediate vicinity of the A320. There were two aircraft 20nm and 35nm West and slightly above the level of the A320 and one aircraft 20 miles ahead of the A320 at the same level. It was considered possible that given the position of the sun, these aircraft may have been glinting in the sun. However, it was not possible to trace the object or determine the likely cause of the sighting.

Summary An A320 pilot, in Northbound level cruise at FL340, perceived an object through the LH DV window which he assessed as travelling towards him at the same level, slightly above the flight deck windscreen. There were no aircraft in the vicinity indicated on TCAS or on radar. There were no recorded releases of meteorological balloons in the area. PART B: SUMMARY OF THE BOARD'S DISCUSSIONS Information available included a report from the A320 pilot, radar video recordings and a report from the appropriate ATC authority. The Board established that there did not appear to be any conflicting traffic on radar and that no TCAS alerts or advisories had been issued. The involvement of a meteorological balloon was ruled out and it was calculated that a helium filled envelope would have to be of the order of 1m in diameter to reach FL340, hence ruling out commercially available toy balloons. Nevertheless, the A320 pilot was subject to a powerful impression of immediate danger, caused by his perception of an object closing rapidly on his aircraft. Although only supposition, members opined that this may have been due to a combination of a possible reflection from the low sun off one of the aircraft to the West, and of the pilot’s head movement as he looked forward. After some discussion it was decided that, although the reflection theory held some merit, the overall dearth of information relating to the event rendered a meaningful finding impossible. PART C: ASSESSMENT OF CAUSE AND RISK

Cause: Sighting report. Degree of Risk: D. ERC Score4: N/S


1

AIRPROX REPORT No 2013100 Date/Time: 6 Aug 2013 1745Z

Position: 5130N 00032E (2nm W London City Airport - elevation 19ft)

Airspace: Lon/City CTR (Class: D)


Type: RJ1H R44

Operator: CAT Civ Pte

Alt/FL: 1200ft 2000ft QNH (1015hPa) QNH (1016hPa)

Weather: VMC CLBC VMC NK

Visibility: >10km NK


0ft V/0.5nm H NK V/0.5nm H


300ft V/0.5nm H PART A: SUMMARY OF INFORMATION REPORTED TO UKAB THE RJ1H PILOT reports he was inbound IFR to London City airport, in contact with the Tower (TWR) controller. All external lights were switched on (landing, strobes, logo, navigation and wing). SSR Modes C and S were selected, code 6735. Whilst established on the ILS approach to RW09 he received traffic information (TI) initially from City Radar, frequency 128.025MHz and then from London City TWR, frequency 118.075MHz, about a helicopter over the River Thames, E of Canary Wharf, S of his aircraft in his 9 o’clock (sic) position. The First Officer was in visual contact with this traffic. After passing the Outer Marker he received a TCAS TA and then an RA “Descend”. As he was fully established on the ILS RW09, in visual contact with the corresponding traffic, he continued the steep approach for landing on RW09. He assessed the risk of collision as ‘None’. THE R44 PILOT reports his helicopter has a black fuselage. SSR Mode C, code 7050, was selected. He was on a VFR flight in the London City, Class D, CTR under the control of City Radar. He was holding at the Isle of Dogs, instructed to proceed N behind the RJ1H. He circled and then held in a hover. He held at the Isle of Dogs until he saw the aircraft when it passed N abeam on final approach at approximately 3nm. He watched it until it was almost straight ahead and then began to accelerate and move forward. He passed at least 1nm behind the RJ1H. He assessed the risk of collision as ‘None’. THE LONDON CITY WATCH MANAGER reports that the RJ1H pilot reported to City Tower, after landing, that he had received a TCAS RA, at 1747, from a helicopter, which he had had in sight. After receiving an Airprox report from the pilot, he listened to ATC RTF recordings and reviewed the Separation Monitoring Function and observed a helicopter holding at the Isle of Dogs. This helicopter was not talking to City Tower.


RJ1

CPA 1746:26300ft V/0.4nm H

A10

46:1446:02

46:0245:50

1745:38

R44

A12A14A17A20A19

A13A14A15A16A16A16

NM

0 1 2 3

2

Factual Background The London City weather was: EGLC 061720Z 35005KT CAVOK 22/08 Q1015= EGLC 061750Z VRB02KT CAVOK 22/08 Q1015 MATS Part 11 states the ATC responsibilities for Class D airspace:’....Pass traffic information to IFR flights on VFR flights and give traffic avoidance advice if requested; Pass traffic information to VFR flights on IFR flights and other VFR flights’. Analysis and Investigation

CAA ATSI

CAA ATSI had access to written reports from both pilots, area radar recordings, RTF recordings and transcripts of the City Radar frequency and the London City Tower frequency. No report was received from the City Radar controller.

The R44 was receiving a Radar Control Service (RCS) from City Radar. At 1740:20 the R44 was given a clearance to proceed eastbound along the Thames to the Isle of Dogs not above 2000ft VFR.

At 1744:03 the RJ1H, also being provided with an RCS by City Radar, was given a closing heading for the ILS RW09 of 060°.

At 1744:42 the R44 was holding at the Isle of Dogs, in accordance with its clearance, with the RJ1H establishing on final approach (Figure 1). The City Radar controller passed TI on the RJ1H and the R44 reported having the traffic in sight.

Figure 1.

At 1745:10 the RJ1H pilot was informed of the presence of the R44, holding S of a two mile final and was told that the R44 would pass behind him. The RJ1H was transferred to London City Tower. The City Radar controller instructed the R44 pilot, after the RJ1H had passed, to proceed up the Lea Valley not above 2000ft VFR. The controller also instructed the R44 pilot to arrange his flight to pass behind the RJ1H, which was complied with.

1 MATS Part 1, Section 1, Chapter 2, Page 2

3

Summary The Airprox occurred within Class D airspace of the London City CTR. The RJ1H was operating IFR and the R44 VFR. Both the City radar and the London City TWR controllers complied with ATC responsibilities for flights within Class D airspace; appropriate TI was issued to both flights. The R44 was visual with the RJ1H and complied with the City radar’s instruction to pass behind it. The RJ1H received a TCAS RA to descend, which was complied with by descending on the ILS. Neither pilot considered there was any risk of collision. PART B: SUMMARY OF THE BOARD’S DISCUSSIONS Information available included reports from the pilots of both aircraft, area radar recordings, transcripts of the relevant RT frequencies and reports from the appropriate ATC and operating authorities. The Airprox was reported by the RJ1H pilot following receipt of a TCAS RA against an R44 crossing behind. Board members wondered why the pilot of the RJ1H had decided to file an Airprox report as there had been no risk of a collision and both aircraft had been operating as cleared. It transpired that the associated airline’s company reporting form does not have a separate field for reporting TCAS alerts, therefore, it is possible that the Airprox box was used instead. It was noted that there have been a number of similar Airprox reports from the same company operating into LCY. The Board then considered the actions of the pilots. The R44 had been instructed to cross behind the RJ1H, which it had in sight. Although the pilot reported he had headed North from the Isle of Dogs after the RJ1H had passed through his twelve o’clock, radar recordings indicate that he actually set course before the aircraft had crossed. Whilst this complied with the ATC clearance, it resulted in the RJ1H receiving a TCAS RA due to the helicopter’s forward vector then impinging on the RJ1H’s TCAS Protection Volume. Airline members commented that this was due to the high Glide Path angle at London City (5½°), where the aircraft was higher on approach than at other airports such that the RJ1H would still have been above the TCAS Descent RA reporting threshold of 900ft at the time. Civil ATC members stated that it was not possible to cross single-engine helicopters further to the west due to operating restrictions. The Board members agreed that the cause of the Airprox had been the TCAS RA received by the RJ1H due to the R44 flight vector. However, there was considerable discussion over the associated risk and, specifically, whether it should be classified as a Category C (no risk of collision) or a Category E (normal procedures, safety standards and parameters pertained). Many members considered that, because this was normal operations at LCY, with no risk of collision, an E was appropriate. However, it was equally pointed out that it should not be normal procedure to receive a TCAS RA on final approach (or at any other time in flight). The definition of a Category E is that: "an incident meets the criteria for reporting, but, by analysis, it was determined that the occurrence was so benign that it would be misleading to consider it an Airprox occurrence. Normal procedures, safety standards and parameters pertained", the key consideration was therefore whether 'normal procedures, safety standards and parameters pertained’. After much debate, it was decided that normal procedures and parameters had in fact pertained (in as much as the LCY 5½° approach is an unusually steep approach compared to other airfields) and that integrated operations conducted as in this case had met ‘normal safety standards’ because there had been no risk of collision or breakdown in situational awareness by the pilots, who had both received timely Traffic Information from ATC and had had each other in sight before the TCAS system had generated the RA. Notwithstanding, the Board remained very concerned that TCAS RA warnings should not be considered as ‘normal’ at any time. They therefore resolved to recommend that the CAA reviews TCAS interaction between local traffic and CAT inbound and outbound LCY in order to determine how operating procedures might be modified to avoid similar occurrences.

4

PART C: ASSESSMENT OF CAUSE AND RISK Cause: Although well clear of the other aircraft, and with it in sight within Class D

airspace, following appropriate TI from ATC, the R44 flight vector generated a TCAS RA in the RJ1H.

Risk: E ERC Score2: 1. Recommendation: The CAA reviews TCAS interaction between local traffic and CAT inbound and

outbound LCY.


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