Trying to fly attitude in an Airbus fbw aircraft is very difficult in normal law as you are commanding a pitch rate.
If the crew had made a poor response the aircraft may have gone into this mode:
ABNORMAL ATTITUDE FLIGHT LAW
A completely different law emerges automatically when the aircraft is in an extreme upset as follows:
* pitch attitude > 50 deg nose up or > 30 deg nose down
* bank angle > 125 deg
* AOA > 30 deg or >-10 deg
* speed > 440 kts or < 60 kts
* mach > M0.96 or < M0.1
The abnormal attitude law is:
- PITCH ALTERNATE with no protection except LOAD FACTOR protection. No automatic pitch trim.
- ROLL DIRECT with full authority
- YAW ALTERNATE
After recovery the flight law reverts to:
- PITCH ALTERNATE law
- ROLL DIRECT law
- YAW ALTERNATE
The aircraft returns to a degraded mode (not normal law as usual) because there is a certain level of suspicion about its ability to control the aircraft (that is how could it have got to the extreme flight state in the first place? The protections should have intervened well before the pitch, bank, AOA, speed and mach limits above).
There was a similar incident in the North Atlantic a number of years ago when an A340 had a speed upset and rapidly departed its alloted level.
Last edited by tubby linton; 7th Oct 2008 at 21:04.