1. Landing in CONF 3 – Use of reversers
Hélène REBEL
Head of A330/A340 Operational Standard
Presented by:
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
April 2007

3. General considerations
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.
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
Landing in CONF 3 - Use of reversers
April 2007

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
April 2007

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
April 2007

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
April 2007

7. Fuel economy estimation
Simulation hypothesis – Cont’d
1500 ft:
S/F configuration for landing: CONF 3 or FULL
70 kts *
REV IDLE
REV MAX
LANDING AT REV MAX
0 kt
* 85 kts for Wide Body aircraft
1500 ft:
S/F configuration for landing: CONF 3 or FULL
REV IDLE
LANDING AT REV IDLE
0 kt
1500 ft:
S/F configuration for landing: CONF 3 or FULL
IDLE THRUST
LANDING WITH NO REV
0 kt
Landing in CONF 3 - Use of reversers
April 2007

8. Fuel economy estimation
RESULTS
Average fuel consumption increase in kg between
REV MAX and
REV IDLE
REV IDLE and
No REV
CONF FULL
and
CONF 3
CONF FULL / REV MAX
CONF 3 / REV IDLE
A320
family
10 to 15
15 to 20 2
5 to 15
15 to 30
20 to 40
A330
25 to 45
40 to 60 5
10 to 25
40 to 55
60 to 75
A /300 35 40 15 50 60
A /600 65
85 to 90 10 75 95
A300
30 to 40
50 to 65 3
15 to 25 80
Light weight
Heavy weight
Landing in CONF 3 - Use of reversers
April 2007

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
April 2007

10. Other operating cost considerations
Thrust Reversers
Lower reversers thrust  Reduction of FOD risk and associated maintenance
Direct Maintenance Cost (DMC) is mainly affected by thermal cycling or age of the materials
Deployment of reversers has a minor impact in DMC
 No advantage to do a landing without reversers
Landing in CONF 3 - Use of reversers
April 2007

11. Other operating costs consideration
Tires
Tire wear is affected by several parameters which are mainly:
Loads
Pressure
Ground surface roughness
Temperature
Aircraft roll
Straight line rolling:
20% to 30%
Maneuvering :
10% to 20%
Touch down:
Braking:
20% to 40%
 If basic braking recommendations are applied: Overall tire DMC impact is likely to be small
Landing in CONF 3 - Use of reversers
April 2007

12. Other operating costs consideration
Brakes
Example of brake energy difference depending on the approach speed and the use of reverse : A
Autobrake LO
Braking Energy (106 J / wheel)
REV MAX
REV IDLE
No REV
CONF FULL
(30/40) 9 18 14 27 33
CONF 3
(15/20) 10 20 15 40
Slight increase
Multiplied by 1.5
Multiplied by 2
 Increasing the approach speed and/or using Rev Idle will lead higher brake temperature
Landing in CONF 3 - Use of reversers
April 2007

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
April 2007

14. Other operating costs consideration
Brakes: Effect on Carbon Brake wear
Carbon brake wear is mainly affected by:
Number of brake applications
 Not linked to the approach conf or the use of reversers
Landing in CONF 3 - Use of reversers
April 2007

15. Other operating costs consideration
Brakes: Effect on Carbon Brake wear
Carbon brake wear is mainly affected by:
The brake temperature
Messier - Bugatti
Honeywell-ALS
BF Goodrich
Wear rate 80
Indicated temperatureC
250
150
315
500
 Optimum brake temperature range is still compatible with such operations
Landing in CONF 3 - Use of reversers
April 2007

16. Other operating costs consideration
Brakes: Effect on Carbon Brake thermal oxidation
Thermal oxidation is temperature and time related:
Repetitive high temperature occurrences
Long duration of carbon exposure to high temperature
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
April 2007

17. Other operating costs consideration
Brakes: Effect on Carbon Brake thermal oxidation
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
Landing in CONF 3 - Use of reversers
April 2007

18. Other operating costs consideration
Brakes: General guidelines
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.
Landing in CONF 3 - Use of reversers
April 2007

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
April 2007

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
April 2007

21. Operational consequences
Use of reversers at Idle:
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
Landing in CONF 3 - Use of reversers
April 2007

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
April 2007

23. Pro and Cons: Summary
The economics vary a lot from one airline to another but pro and cons can be summarized as follows:
Landing in CONF 3
Use of Idle reverse thrust
Fuel economy
Noise reduction
FOD
Tires DMC
Thrust reversers DMC
Tailstrike margins
Brake wear
Brake oxidation
Brake cooling time
Runway occupancy time
Landing in CONF 3 - Use of reversers
April 2007

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
April 2007

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
April 2007

26. Good Dispatcher and Flight Crew awareness is necessary
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
April 2007