Application of Wake TurbulenceApplication of Wake TurbulenceSeparation at London HeathrowSeparation at London Heathrow

Paul JohnsonDevelopment Manager

NATS Heathrow

Passengers per year 67 MillionAircraft movements per year 470,000

Traffic Mix 31% Heavy, 69% Medium or below

Typical BusiestDay 1350 1382Hour 88-92 100

Inbounds 42-44Outbounds 46-48

Heathrow Vital StatisticsHeathrow Vital Statistics

Runways 27L & 27R Runway Alternation:Landing runway changes at 15:00

06:00 to 15:0015:00 to 23:30

Runways 09L & 09R Landing Runway 09LDeparture Runway 09R

TEAM In peak periods allows up to 6 additionallanding aircraft on the Departure runway

Noise RestrictionsNoise Restrictions

Wake CategoriesWake Categories

HEAVYMEDIUMLIGHT

A300B747

B757B707DC8

A318 A321FK100 TU54

DHC7 FK70Pa34 DA20

>162,000kg>104,000kg<162,000kg

>40,000kg<104,000kg

>17,000kg<40,000kg

<17,000kg

HEAVYUPPERMEDIUM

LOWERMEDIUM

SMALLLIGHT

NATS

>136,000kg>7,000kg

<136,000kg<7,000kg

ICAO

Separation Requirements are;LEADER FOLLOWER SPACING (NM)

HeavyHeavyHeavyHeavyHeavy

HeavyUpper MediumLower MediumSmallLight

45567

Upper MediumUpper MediumUpper MediumUpper MediumUpper Medium

HeavyUpper MediumLower MediumSmallLight

3446

Lower MediumLower MediumLower MediumLower MediumLower Medium

HeavyUpper MediumLower MediumSmallLight

35

SmallSmallSmallSmallSmall

HeavyUpper MediumLower MediumSmallLight 3

LightLightLightLightLight

HeavyUpper MediumLower MediumSmallLight

Notes:

•Wake Vortex Separation applied to 4DME fromtouchdown.•When the lead aircraft is inside 4DME and a reductionof ½ mile or more in the required wake vortex separationoccurs, the pilot of the following aircraft must beinformed.•Heathrow Final Director (FIN) responsible for providingappropriate spacing to achieve this.•Tower controller responsible for informing FIN ofrequirements related to runway occupancy time.

Separation for Wake Vortex reasons is not necessary.

•Minimum radar separation on final approach 3nm.•2.5nm minimum radar separation can be applied underspecified conditions.

Wake Encounters by AltitudeWake Encounters by Altitude

0

10

20

30

40

50

60

70

80

<=500 <=1000 <=2000 <=3000 <=4000 <=5000 <=6000 <=7000 <=8000 <=9000 <=10000

Altitude of Encounter (ft)

Num

ber

of E

ncou

nter

s be

twee

n 20

00 a

nd 2

004

H

H

H

Heathrow

Gatwick

London City

Luton Stansted

10 Nm

20 Nm30 Nm

Heathrow

London City

OCKBIG

LAM

BNN

Heathrow

London City

OCK

BIG

LAM

BNN

Heathrow

London City

OCK

BIG

LAM

BNN

Heathrow

London City

OCK

BIG

LAM

BNN

Heathrow

London City

OCK

BIG

LAM

BNN

Heathrow

London City

OCK

BIG

LAM

BNN

IntermediateNorth (INT N)

IntermediateSouth (INT S)

FinalDirector (FIN)

Heathrow

London City

OCK

BIG

LAM

BNN8,000ft

and above

8,000ftand above

5,000ft -8,000ft

4,000ft3,000ft

220kts 220kts

180kts160kts

H

HeathrowLondon City

9 Miles 11 Miles 13 Miles

2500ft3000ft

4000ft

H

HeathrowLondon City

9 Miles 11 Miles 13 Miles

2500ft3000ft

4000ft

H

HeathrowLondon City

9 Miles 11 Miles 13 Miles

2500ft3000ft

4000ft

H

HeathrowLondon City

9 Miles 11 Miles 13 Miles

2500ft3000ft

4000ft

Heathrow 4 DME

2.5 Miles120-140Kts

3 Miles160 Kts

68 Sec 68 Sec

Heathrow 4 DME

4.5 Miles

No Wind

5 Miles

113 Sec 113 Sec

Heathrow 4 DME

5 – 6 Miles

Headwind Wind

5 Miles

Pull Away situation causesloss of runway capacity

Heathrow 4 DME

4 Miles

Tailwind Wind

5 Miles

Catch up situation

Heathrow 4 DME

4.5 Miles

Tailwind Wind

6 Miles

Catch up situation requiresextra spacing outside 4 DME

Tower RequirementsTower RequirementsAnd ResponsibilitiesAnd Responsibilities

• Check Separation provided on ATM• Inform pilot if catch up more than half a mile• Monitor separation below 500ft• Monitor runway occupancy time• Monitor landing clearance margins• Consider variation between types• Provide feedback to radar

This is an interactive process

Tower RequirementsTower RequirementsAnd ResponsibilitiesAnd Responsibilities

Go-aroundsTypical go-around rates at HeathrowOf the order of 50 per month (1-2 per day)Normally only 1-2 per month due Wake Vortex

Strategies to avoid go-aroundsApproach and Tower controller interactionRadar aware of type and speed variationsInform pilot if catch up more than half a mile (visual)Visual switchGo-around

Preservation of separation

Departure SeparationsDeparture Separations

Diverging routes1 minute(or less using visual separation)

Same Route2 minutes(alternatively 5 miles radar separation)

Wake Vortex2 minutes(3 minutes when departing from an intersection)

SummarySummary• Segregated parallel runway operation

• Large numbers of queued pairs

• Small amount of airspace

• Holding enables Batching of wake categories

• Approach pattern and Continuous Descent Approaches creates wake “hotspots” where traffic patterns mergeand at 3000ft-4000ft on final approach

• Maximum half a mile catch up permitted inside 4 DME

• Aircraft performance and wind effects taken into account

• Interactive process between Tower and Approach to ensure that separation is preserved

Any Questions?Any Questions?