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Section/division Occurrence Investigation Form Number: CA 12-12b

AIRCRAFT INCIDENT REPORT AND EXECUTIVE SUMMARY

Reference: CA18/3/2/0849

Aircraft Registration ZS-OTF

Date of Incident 15 June 2011 Time of Incident 0800Z

Type of Aircraft Boeing 737-436 Aircraft Type of Operation Scheduled Domestic Flight

Pilot-in-command Licence Type Airline Transport Age 62

Licence Valid Yes

Pilot-in-command Flying Experience

Total Flying Hours

PIC: 21780.0 1st Officer: 2218.0

Hours on Type

PIC: 6800.0 1st Officer: 170.9

Last point of departure O.R Tambo International Aerodrome (FAJS) Gauteng Province

Next point of intended landing Cape Town International Aerodrome (FACT) Western Cape Province

Location of the Incident site with reference to easily defined geographical points (GPS readings if possible)

O.R Tambo International Aerodrome (FAJS) Gauteng Province at GPS position S26° 08.02’ E028° 14.34’

Meteorological Information

Fine weather conditions prevailed at the time of the incident. The wind was calm at

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Section/division Occurrence Investigation Form Number: CA 12-12a

AIRCRAFT INCIDENT REPORT

Name of Owner/Operator : Lexshell 779 Investments (Pty) Ltd / Comair (Pty) Ltd Manufacturer : Boeing Aircraft Company Model : 737-436 Nationality : South African Registration Marks : ZS-OTF Place : O.R Tambo International Aerodrome (FAJS)

Gauteng Province Date : 15 June 2011 Time : 0800Z All times given in this report are Co-ordinated Universal Time (UTC) and will be denoted by (Z). South African Standard Time is UTC plus 2 hours. Purpose of the Investigation : In terms of Regulation 12.03.1 of the Civil Aviation Regulations (1997) this report was compiled in the interest of the promotion of aviation safety and the reduction of the risk of aviation Incidents or incidents and not to establish legal liability. Disclaimer: This report is given without prejudice to the rights of the CAA, which are reserved.

1. FACTUAL INFORMATION 1.1 History of Flight 1.1.1 On 15 June 2011 at approximately 1000Z, during daytime conditions, flight BA413

(ZS-OTF) took-off from Rwy 03L at O.R Tambo International Aerodrome on a scheduled domestic flight to Cape Town International Aerodrome.

1.1.2 During the take-off run, the number 1 tire tread separated and caused minor damage to the aircraft.

1.1.3 After the take-off, debris, including tire tread and a wheel-well slave door, were found on the runway at O.R Tambo. The captain was advised about the thread separation but elected to continue with the flight. The Aerodrome Rescue and Fire Fighters at Cape Town International Aerodrome was alerted.

1.1.4 The remainder of the flight to Cape Town was uneventful and the landing did not result in any emergency.

1.1.5 After disembarking the passengers, an inspection revealed damage to the flap(s) in the direct vicinity of the #1 wheel and tire as well as to the left hand landing gear doors.

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1.2 Injuries to Persons

Injuries Pilot Crew Pass. Other Fatal - - - - Serious - - - - Minor - - - - None 2 4 81 0

1.3 Damage to Aircraft 1.3.1 The aircraft sustained minor to substantial damage to the left hand flaps and the

outer centre and lower slave doors. The inner slave door was missing and most of the rod ends in that area sustained damage during the incident.

1.4 Other Damage 1.4.1 There was no other damage to any buildings, vehicles, navigation facilities,

aerodrome structures and installations or any damage to the environment. 1.5 Personnel Information

Captain:

Nationality South African

Gender Male Age 62

Licence Number 0270088701 Licence Type Airline Transport Licence valid Yes Type Endorsed Yes Ratings Instrument Medical Expiry Date 31 October 2011

Restrictions Corrective lenses Annual Urulogist’s report

Previous Incidents None Flying Experience:

Total Hours 21780 Total Past 90 Days 76.5 Total on Type Past 90 Days 76.5 Total on Type 6800

1st Officer / Co-pilot

Nationality South African Gender Male Age 38

Licence Number 0272297151 Licence Type Airline Transport Licence valid Yes Type Endorsed Yes Ratings Instrument Medical Expiry Date 31 October 2011 Restrictions Corrective lenses Previous Incidents Nil

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Flying Experience:

Total Hours 2218 Total Past 90 Days 74.3 Total on Type Past 90 Days 74.3 Total on Type 170.9

1.6 Aircraft Information

Airframe : Type Boeing 737-436 Serial Number 25305 Manufacturer Boeing Aircraft Company Date of Manufacture 1991 Total Airframe Hours / Cycles (At time of Incident)

42461.59 / 30671.0

Last C-check (Date & Hours) 12 June 2011 42442.25 Hours since Last C-check 19.34 C of A (Issue Date) 18 January 2002 C of R (Issue Date) (Present owner) 11 January 2002 Operating Categories Standard

Engine 1: Type CFM56-3C1 Serial Number 723158 Hours since New 65435 Cycles since New 52522 Hours / cycles since last C-check 65354 / 52460

Hours / cycles since O/H N/A – Engine on condition Engine 2: Type CFM56-3C1 Serial Number 856380 Hours since New 41483 Cycles since New 27993 Hours / cycles since last C-check 41402 / 27931

Hours since O/H N/A – Engine on condition

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Tire #1 Record: (See Appendix A” for Tire Manufacturer Report)

Make & Description

Dunlop Bridgestone H40x14.5 – 19 / 26PR*225MPH

Pattern F2D Part Number APS01337 BS Serial Number 608NH092 Hours / cycles since New 8812 / 6335 Hours / cycles since O/H 257 / 45 TBO cycles 1800

1.7 Meteorological Information

Wind direction Calm Wind speed

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1.10 Aerodrome Information

Departure Aerodrome:

Aerodrome Location O.R Tambo International Airport

Aerodrome Co-ordinates S26° 08.02’ E028° 14.34’ Aerodrome Elevation 5558 ft ASL Runway Designations 03R/21L 03L/21R Runway Dimensions 3400m x 60m 4418m x 60m Runway Used 03L Runway Surface Tarred Approach Facilities Not applicable

After the take-off, debris, including tire tread and a wheel-well slave door, were found on the runway.

Destination Aerodrome:

Aerodrome Location Cape Town International Airport

Aerodrome Co-ordinates S33° 58.05’ E018° 36.19’ Aerodrome Elevation 151 ft ASL Runway Designations 01/19 Runway Dimensions 3201m x 60m Runway Used 01 Runway Surface Tarred Approach Facilities Not applicable

1.11 Flight Recorders 1.11.1 The aircraft was equipped with a flight data recorder and a cockpit voice recorder.

Neither recorder was downloaded following the incident. 1.12 Wreckage and Impact Information 1.12.1 Minor damage was sustained by the upper and mid flap lower surfaces and

substantial damage to the lower flap.

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Figure 1: Damage to the upper and mid flap lower surfaces and the lower flap.

Figure 2:Damage to the lower surface of the lower flap.

1.12.2 The outer centre and lower slave doors also sustained minor damage. The inner

slave door was missing and most of the rod ends in that area sustained damage.

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Figure 3: Damage to the lower Landing gear door.

Figure 4: Damage to the number 1 tire.

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1.13 Medical and Pathological Information 1.13.1 Not applicable. 1.14 Fire 1.14.1 There was no evidence of fire in flight or after the impact. 1.15 Survival Aspects 1.15.1 Not applicable. 1.16 Tests and Research 1.16.1 The tire in was dispatched to the manufacturer for further examination as to the

cause of the thread separation. 1.16.2 According to the manufacturer there was sufficient evidence to conclude that there

was a mechanical breakdown of adhesion within the 5 ply casing repair plug between the repair rubber and casing cord structure. Examination showed that the break down has developed over a small number of landings.

1.16.3 It is clearly evident that during the last take-off the break down was exacerbated

due to the weight of the unworn thread which was sufficient to pull away from the casing due to significant centrifugal forces imparted during take-off at a high airport and at the maximum aircraft loading and take-off speed.

1.16.4 The tire was found to be completely satisfactory on shearography inspection and

the tire was retreaded and final inspected in accordance with approved retread procedures and specifications.

1.17 Organizational and Management Information 1.17.1 The operator was in possession of a valid AOC. 1.17.2 According to available documentation, the aircraft was maintained as required by

the manufacturer and the Regulator and the maintenance organization was in possession of a valid maintenance certificate.

1.18 Additional Information 1.18.1 Not applicable. 1.19 Useful or Effective Investigation Techniques 1.19.1 Not applicable.

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2. ANALYSIS 2.1 The aircraft took off from O.R Tambo International Aerodrome on a scheduled

domestic flight to Cape Town International Aerodrome. During the take-off run, the number 1 tire tread separated. After the take-off, debris, including tire tread and a wheel-well slave door, were found on the runway at O.R Tambo. The captain was advised about the thread separation but elected to continue with the flight. The Aerodrome Rescue and Fire Fighters at Cape Town International Aerodrome was alerted, however, the remainder of the flight to Cape Town was uneventful and the landing did not result in any emergency. After disembarking the passengers, an inspection revealed damage to the flap(s) in the direct vicinity of the #1 wheel and tire as well as to the left hand landing gear doors. It is evident that the operator operates under severe operating conditions and it is considered possible that the maximum performance of the aircraft may have been beyond the capability of this approved repair process.

3. CONCLUSION 3.1 Findings 3.1.1 The flight crew were licensed and qualified for the flight in accordance with existing

regulations. 3.1.2 The maintenance records indicated that the aircraft was equipped and maintained

in accordance with existing regulations and approved procedures. 3.1.3 The weather did not contribute to this incident 3.1.4 There was an effect on Air traffic control 3.2 Probable Cause/s 3.2.1 Mechanical breakdown (thread separation) of adhesion within the casing repair plug

between the repair rubber and casing cord structure of number 1 tire, during take-off.

3.3 Contributing Factor(s): 3.3.1 Severe operating conditions, using high airports and maximum performance of the

aircraft. 4. SAFETY RECOMMENDATIONS 4.1 Since the operator operates under severe operating conditions, it was considered

possible that the maximum performance of the aircraft may have been beyond the capability of this approved repair process. With this in mind, it is strongly recommended that the SACAA Airworthiness Section should examine the possibility of revising the approved conditions for this repair

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process, especially when these tires are used at high elevation airports at severe operating conditions.

5. APPENDICES 5.1 Appendix A” – Tire Manufacturer Report.

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Compiled by: JJ du Plessis Date: 30 November 2011 For: Director of Civil Aviation Investigator-in-charge: JJ du Plessis Date: 30 November 2011 Co-Investigator: N/A Date: N/A