From Norman Stanley Fletcher and some others :
..."to give you a feel for what the pilots may have experienced, these are the paramaters that would have to occur for Abnormal Attitude Law to be invoked:
Pitch attitude > 50° nose up or 30° nose down
Bank angle > 125°
Angle of attack > 30° or < - 10° (- 15° for A319 and A321)
Speed > 440 knots or < 60 knots
Mach > 0.91 or < 0.1..."
All the above is correct as are all the posts dealing with flight control reversions.
They, IMHO, are hardly applicable in this case as :
- They were on autopilot
- A passenger was quoted as reporting that the captain came on the PA and said that " the A/P had been knocked-out and they were flying manually".
- This points to an A/P disconnect.
The conditions are a lot smaller than those for a reversion :
-High speed protection is active (Vmo bust)
-Alpha protection is active (AoA greater than Alpha prot +1° )
-Pitch attitude over 25° nose up or 13° nose down
-Bank angle in excess of 45°
As everybody was talking about 50 to 60° bank angles and some porpoising, one at least of these reported values could have triggered an A/P disengagement.
Please note that in this case, they could have re-connected the A/P when calm conditions were resumed. The reason why they - apparently - did not could be explained by caution and - maybe - confusion as to the causes of the upset.