Originally Posted by
Machinbird
3Hole
Don't you see a problem with an aircraft with an automatic trim system that trims silently? For years we have had alerting devices on THS trim movement (clackers & whoolers) to let you know the thing is moving. Then comes the new guy on the block with a "better" idea. (Airbus)
And yet autotrim (up into a stall) is still catching out boeing pilots too. The bus (outside of direct/boeing law) will at least wind the trim back down if ask for nose down. Wheras it seems the 737 at least will wind the trim up to the stall warning and then leave the pilot to remember (or not...) to unwind it in recovery. Which is "better" ??
But no one saw the trim move. No one heard it move. If they had thought about it, they should have anticipated it moving, but they had other problems and it bit them.
The trim would have moved straight back down had they requested nose down beyond what the elevators could deliver. They didn't. They needed what 30deg(?) nose down to recover - never asked fro anything close. There was no stall recovery attempt that was stopped by the trim, there was no stall recovery attempted - period.
Had the trim movement kicked the crew in the rear or slapped them in the face for every degree it would have made no damn difference - they would have said yes trim me up,
I'm trying to climb and the elevators aren't working... Had the THS ignored them and (say) gone to neutral, they would have overidden it with elevator all the way down. Had
they had spotted it ignoring them, they would probably have manually trimmed back up (and what should the poor plane do then?). Why?
Because they wanted to climb.
They were pitched up 15deg, falling out of the sky, plane not responding to controls [also low airspeed but they aren't sure on that]... and they had no clue they were stalled. Never mentioned. No (verbal) response to the stall warning - except perhaps "
I’m in TOGA eh" [so I can't be stalled?] Throttles forward, stick hard back, why aren't we climbing ? "
But we’ve got the engines what’s happening"
Sure, make the trim wheel clack, and in this case it's going to do all it's clacking during that 1min continuous stall warning. They didn't hear that, why would they hear the trim clack ?