Quote: Ian W
However, into this action PF was putting in as much aileron as he could, often apparently full SS. The result of this would be to make the low wing AOA higher so less lift so a tendency for the aircraft to apparently do the opposite of what was wanted until the wing sweep effect was larger than the aileron AOA effect.
I think it was the increased drag and not the higher AOA, i agree though that it looks like it did not help in leveling the wings.
rudderrudderrat
i don't know the physics of stalled aircraft behaviour, but I think the stability was a result of dihedral rather than sweep.
When stalled, if one wing is lower, it presents a greater plan surface area to the airflow than the higher wing, resulting in a levelling couple.
I tend to agree. Dihedral helped, sweep back did not help.
I think PF's roll input would help level the wings because the lowered aileron would present more drag. (edit in the same way that down elevator lowered the nose and reactivated the stall warning)
Here i disagree again. See my post from few days ago
Adverse yaw
From
follow up post Honestly i donīt know how this missing sideslip estimation influences the behaviour of the rudder in a stall, or how the functioning yaw damping influences it in a positive or negative way. But hopefully somebody can explain.
Would somebody be able to explain on my followup question concerning the function of yaw dampening and missing side slip estimation in Alt2?
BOAC
Quite a few folk here just a bit confused about aircraft, and in particular swept wing, stability, but I don't actually think any of this is relevant to this thread.
I agree inthe way, that it did not play a role causing this upset.
But i strongly disagree in general.
The aerodynamic behaviour of the aircraft seems to be a blanc card in nowadays training and knowledge base. We wonder, wy the pilot pulled the stick despite being in a stall. We might also wonder, why he applied full left aileron and not using rudder to level the wings. It might have the same reason: Not knowing, what the outcome in an aerodynamic point of view) theses actions would be. He wanted to stop the descent and climb up again, therefore pull back on the stick. That worked probably more than 99% of his flying career. Tell the aircraft what to do, point the nose up and apply sufficient power, and the aircraft will follow the orders. Same with bank. If right wing is down, put the SS to the left. When the wing is level, put the stick to neutral and it will stay there. That worked again more than 99% of his flying career.
Unfortunately there are situations, when you have to switch from normal behaviour to "trouble shooting mode", and for that you have to know the performance envelope of your aircraft and how it behaves, if you touch that envelope or go outside of it.
Military fast jet pilots do that on a day to day basis, therefore they know exactly how the aircraft will behave and and how to react by flight control input to get the desired result.
This crew had no clue what might have helped to get out of the situation they themselves flew (stalled) into. Agreed, they should not have gotten into this situation first hand, but thatīs what īs happening in our non perfect technical and human world.
Therefore again, i tend to say, that it is also very important to look into those issues after the stall happened instead of exchanging arguments about tactile feedback and yoke Vs.SS the 50th. time. We placed those statements and they stand from either side.