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Landing in CONF 3 – Use of reversers

Presented by:. Hélène REBEL Head of A330/A340 Operational Standard. Landing in CONF 3 – Use of reversers. General considerations. Airbus Flight Crew Operating Manuals recommendation. CONF FULL – Maximum Reverse thrust. Maximize safety margins. General considerations.

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Landing in CONF 3 – Use of reversers

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

  2. General considerations Airbus Flight Crew Operating Manuals recommendation CONF FULL – Maximum Reverse thrust Maximize safety margins Landing in CONF 3 - Use of reversers

  3. General considerations • Above all, the first considerations must be: • The aircraft landing weight • The runway length • The braking means • The runway surface conditions • The tailwind • Autoland not certified in CONF 3 (CONF 15/20) for A300/A310 aircraft family • For economics, airlines could envisage: • Approach in CONF 3 • Idle or no reverse thrust at landing All operational and economics consequences have to be considered. Landing in CONF 3 - Use of reversers

  4. Content General considerations Fuel economy estimation Additional considerations: Other operating cost considerations Operational consequences Pro and Cons: Summary Conclusion Landing in CONF 3 - Use of reversers

  5. Fuel economy estimation • Depends on several parameters as: • Aircraft / Engine type • Aircraft weight during the approach • Approach speed • Autobrake selection • Airport elevation • The ISA conditions • … Fuel economy estimation Landing in CONF 3 - Use of reversers

  6. Fuel economy estimation • Simulation hypothesis • Airport elevation: Sea Level • ISA conditions • Approach speed VLS + 5 knots • Autobrake LO • 2 aircraft weights: light and heavy weights Landing in CONF 3 - Use of reversers

  7. Fuel economy estimation LANDING AT REV MAX REV IDLE 1500 ft: S/F configuration for landing: CONF 3 or FULL REV MAX 0 kt 70 kts * * 85 kts for Wide Body aircraft LANDING AT REV IDLE REV IDLE 1500 ft: S/F configuration for landing: CONF 3 or FULL 0 kt LANDING WITH NO REV IDLE THRUST 1500 ft: S/F configuration for landing: CONF 3 or FULL 0 kt • Simulation hypothesis – Cont’d Landing in CONF 3 - Use of reversers

  8. Fuel economy estimation Light weight Heavy weight • RESULTS Landing in CONF 3 - Use of reversers

  9. Content General considerations Fuel economy estimation Additional considerations: Other operating cost considerations Operational consequences Pro and Cons: Summary Conclusion Landing in CONF 3 - Use of reversers

  10. Other operating cost considerations • 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 Landing in CONF 3 - Use of reversers

  11. Other operating costs consideration Touch down: 20% to 30% Maneuvering : 10% to 20% Braking: 20% to 40% Straight line rolling: 20% to 30% • Tire wear is affected by several parameters which are mainly: • Loads • Pressure • Ground surface roughness • Temperature • Aircraft roll • Tires  If basic braking recommendations are applied:Overall tire DMC impact is likely to be small Landing in CONF 3 - Use of reversers

  12. Other operating costs consideration Example of brake energy difference depending on the approach speed and the use of reverse : A300-622 Autobrake LO Slightincrease Multiplied by 1.5 Multiplied by 2 • Brakes Increasing the approach speed and/or using Rev Idle will lead higher brake temperature Landing in CONF 3 - Use of reversers

  13. Other operating costs consideration • Brakes • In general carbon brake life is affected by • Carbon brake wear • Carbon brake oxidation • Catalytic oxidation • Thermal oxidation Landing in CONF 3 - Use of reversers

  14. Other operating costs consideration • 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 Landing in CONF 3 - Use of reversers

  15. Other operating costs consideration Messier - Bugatti Honeywell-ALS BF Goodrich Wear rate 80 150 250 315 500 0 Indicated temperatureC • The brake temperature • Brakes: Effect on Carbon Brake wear • Carbon brake wear is mainly affected by: •  Optimum brake temperature range is still compatible with such operations Landing in CONF 3 - Use of reversers

  16. Other operating costs consideration • 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 Landing in CONF 3 - Use of reversers

  17. Other operating costs consideration • 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 Landing in CONF 3 - Use of reversers

  18. Other operating costs consideration • 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 Landing in CONF 3 - Use of reversers

  19. Content General considerations Fuel economy estimation Additional considerations: Other operating cost considerations Operational consequences Pro and Cons: Summary Conclusion Landing in CONF 3 - Use of reversers

  20. Operational consequences • 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 Landing in CONF 3 - Use of reversers

  21. Operational consequences • 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: Landing in CONF 3 - Use of reversers

  22. Content General considerations Fuel economy estimation Additional considerations: Other operating cost considerations Operational consequences Pro and Cons: Summary Conclusion Landing in CONF 3 - Use of reversers

  23. Pro and Cons: Summary Landing in CONF 3 Fuel economy Tires DMC Brake oxidation Brake wear Noise reduction Brake cooling time Thrust reversers DMC FOD Runway occupancy time Tailstrike margins • The economics vary a lot from one airline to another but pro and cons can be summarized as follows: Use of Idle reverse thrust Landing in CONF 3 - Use of reversers

  24. Content General considerations Fuel economy estimation Additional considerations: Other operating cost considerations Operational consequences Pro and Cons: Summary Conclusion Landing in CONF 3 - Use of reversers

  25. 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 recommended • System Safety Assessment based on the fact that reversers are deployed at each landing • No real benefit in term of fuel economy Landing in CONF 3 - Use of reversers

  26. 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 use Good Dispatcher and Flight Crew awareness is necessary • Clear Airline policy has to be defined for: • All aircraft types • All considered runways Landing in CONF 3 - Use of reversers

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