Landing in CONF 3 – Use of reversers Hélène REBEL Head of A330/A340 Operational Standard...

Landing in CONF 3 – Use of reversers

Hélène REBELHead of A330/A340 Operational Standard

Presented by:

April 2007 Landing in CONF 3 - Use of reversers © A

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General considerations

Airbus Flight Crew Operating Manuals recommendation

Maximize safety margins

CONF FULL – Maximum Reverse thrust


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• Above all, the first considerations must be:

The aircraft landing weightThe runway lengthThe braking meansThe runway surface conditionsThe tailwindAutoland not certified in CONF 3 (CONF 15/20) for A300/A310

aircraft family

• For economics, airlines could envisage:Approach in CONF 3Idle or no reverse thrust at landing

All operational and economics consequences have to be considered.


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Content


Fuel economy estimation

Additional considerations:

Other operating cost considerations

Operational consequences

Pro and Cons: Summary

Conclusion


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• Depends on several parameters as:

– Aircraft / Engine type– Aircraft weight during the approach– Approach speed– Autobrake selection– Airport elevation– The ISA conditions– …



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• Simulation hypothesis

Airport elevation: Sea LevelISA conditionsApproach speed VLS + 5 knotsAutobrake LO2 aircraft weights: light and heavy weights


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• Simulation hypothesis – Cont’d

1500 ft:

S/F configuration for landing: CONF 3 or FULL

REV IDLE

LANDING AT REV IDLE

0 kt

1500 ft:


IDLE THRUST

LANDING WITH NO REV

0 kt

1500 ft:


70 kts *

REV IDLEREV MAX

LANDING AT REV MAX

0 kt

* 85 kts for Wide Body aircraft


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• RESULTSAverage fuel consumption increase in kg

betweenREV MAX

and

REV IDLE

REV IDLE and

No REV

CONF FULL

and

CONF 3

CONF FULL / REV MAX

and

CONF 3 / REV IDLE

A320

family

10 to 1510 to 15

15 to 2015 to 20

22

22

10 to 1510 to 15

5 to 155 to 15

15 to 3015 to 30

20 to 4020 to 40

A330

family

25 to 4525 to 45

40 to 6040 to 60

55

55

10 to 1510 to 15

10 to 2510 to 25

40 to 5540 to 55

60 to 7560 to 75

A340-200/300

3535

4040

55

55

1515

15 to 2015 to 20

5050

6060

A340-500/600

6565

85 to 9085 to 90

1010

1515

1010

55

7575

9595

A300

family

30 to 4030 to 40

50 to 6550 to 65

33

33

15 to 2515 to 25

15 to 3015 to 30

5050

8080

Light weightLight weight

Heavy weightHeavy weight


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Content







Conclusion


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Direct Maintenance Cost (DMC) is mainly affected by thermal cycling or age of the materials

Deployment of reversers has a minor impact in DMC

• Thrust Reversers

Lower reversers thrust Reduction of FOD risk and associated maintenance

No advantage to do a landing without reversers


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Other operating costs consideration

Tire wear is affected by several parameters which are mainly:– Loads

– Pressure

– Ground surface roughness

– Temperature

– Aircraft roll

If basic braking recommendations are applied:Overall tire DMC impact is likely to be small

Straight line rolling:

20% to 30%Maneuvering :

10% to 20%Touch down:

20% to 30%

Braking:

20% to 40%

•Tires


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• Brakes

Braking Energy (106 J / wheel)REV MAX REV IDLE No REV

CONF FULL

(30/40)

99

1818

1414

2727

1818

3333

CONF 3

(15/20)

1010

2020

1515

3333

2020

4040

Increasing the approach speed and/or using Rev Idle will lead higher brake temperature

Example of brake energy difference depending on the approach speed and the use of reverse : A300-622

Autobrake LO

Slightincrease

Multiplied by 1.5Multiplied by 2


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• Brakes

In general carbon brake life is affected by

– Carbon brake wear

– Carbon brake oxidation• Catalytic oxidation

• Thermal oxidation


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Carbon brake wear is mainly affected by:

– Number of brake applications

Not linked to the approach conf or the use of reversers

• Brakes: Effect on Carbon Brake wear


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– The brake temperature

Messier - Bugatti

Honeywell-ALS

BF Goodrich

0

Wear rate

80Indicated temperatureC

250150 315 500

Optimum brake temperature range is still compatible with such operations

• Brakes: Effect on Carbon Brake wear

Carbon brake wear is mainly affected by:


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Thermal oxidation is temperature and time related:

– Repetitive high temperature occurrences– Long duration of carbon exposure to high temperature

• Brakes: Effect on Carbon Brake thermal oxidation

Thermal oxidation leads to severe brake damage (disk rupture, etc) or loss in braking efficiency

Premature brakes removal


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Increased approach speed Higher brake energy is necessary to stop the aircraft

Rev Idle instead of Rev max Poor sharing of brake energy between reversers and brakes

Depending on flight crew braking management, brake oxidation could be drastically increased

• Brakes: Effect on Carbon Brake thermal oxidation


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To minimize negative effect on the brakes the following could be considered:

– Restrict the application of such procedure to runway where Autobrake LO can be used and is actually used.

– Do not override the autobrake to shorten the landing distance.

– Respect basic Airbus SOP recommendations:

• Delay the brake fans selection for 5 minutes (or at the gate) if turn-around permits.

• Avoid prolonged parking brake application on hot brakes.

• Brakes: General guidelines


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Content







Conclusion


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• Approach in CONF 3:

Higher pitch attitude

May increase the number of alert triggering by the Flight Data Monitoring software

Impact on tailstrike margins

–Tailstrike margins are reduced (except for the A321 aircraft) but, for example, roughly corresponds to:

– 5 to 6 degrees on Single Aisle Aircraft family– 7 to 8 degrees on Long Range Aircraft family

Tailstrike margins remain comfortable


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Potential increase in runway occupancy time and block time

Additional brake cooling time: could be limitative in case of short turn around-time

Must be taken into account for operations

• Use of reversers at Idle:


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Content







Conclusion


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Landing in CONF 3

Use of Idle reverse thrust

Tires DMC

Thrust reversers DMC

Tailstrike margins

Brake wear

Brake oxidation

Brake cooling time

Runway occupancy time

• The economics vary a lot from one airline to another but pro and cons can be summarized as follows:

Fuel economy

Noise reduction

FOD


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Content







Conclusion


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Conclusion

– Airbus recommendation is:

• To maximize safety margins in normal operation, Airbus SOP still recommends to approach in CONF FULL and to use MAX thrust reverse for landing.

• For economics, provided runway length and conditions are favorable, landing in CONF 3 and/or use of idle reverse thrust can be considered.

• No REV landing not recommendedSystem Safety Assessment based on the fact that reversers are

deployed at each landingNo real benefit in term of fuel economy


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Conclusion

• When applying such procedure, to minimize induced negative effect, the following could be considered:

• Restrict the application of such procedure on runway where Autobrake LO can be used and check dispatch conditions.

• Do not override the autobrake to shorten the landing distance

• Pay particular attention on brake fans useGood Dispatcher and Flight Crew awareness is necessaryGood Dispatcher and Flight Crew awareness is necessary

Clear Airline policy has to be defined for:Clear Airline policy has to be defined for:- All aircraft typesAll aircraft types- All considered runwaysAll considered runways

Landing in CONF 3 – Use of reversers Hélène REBEL Head of A330/A340 Operational Standard...

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Transcript of Landing in CONF 3 – Use of reversers Hélène REBEL Head of A330/A340 Operational Standard...