Originally Posted by
RAT 5
At a height of 900 m there was a simultaneous control column nose down input and stabilizer nose down deflection from -2,5 deg (6,5 units) to +2,5 deg (1,5 units) (the FDR recorded a nose down stabilizer input from the stabilizer trim switch of the control wheel lasting 12 seconds, while the CVR record contains a specific noise of rotation of the trim wheels located on both sides of the central pedestal), as a result the aircraft, having climbed to about 1000 m, turned into descent with negative vertical acceleration of -1g.
I still think the answer lies in that quote.
If they pulled -1g to gain the level-off altitude,
I know what you mean, but 'pushed' might be more appropriate. But, moving on: I've read that the CVR recorded the captain's concern as to whether 8000 was set in MCP and the F/O's reply that "yes, here it is." If that was indeed the case why was there a control input at 900m to level off? The FD & HUD would still have been in TOGA climb to 8000. And for anyone to hold the pitch trim for 12 secs is unthinkable unless they were in a frozen state of panic. Both these guys had 1000's of hours and therefore I hope were competent & experienced.
I have been in a rapid climb, nose high, high speed ALT ACQ situation (B757) and reducing power was the game saver as the attitude was rapidly reduced, not trim.
Why level off prematurely would be more to the point. Could this not be the first in the causal chain. Given what appears to be on the face of it, a big heave- ho to arrest the climb in a hurry, an evasive manoeuvre, what could they have possibly been trying to avoid. I would suggest heavy weather seems the most obvious.