Hi,
Originally Posted by Idle Thrust
I have read all four of the threads on this subject so I might have missed something (there's a lot of chaff amongst the wheat here) but has it been established that with the THS at the end of its range (13), with full nose down SS, the elevator would not have enough effect to lower the nose?
There have many posts about using the trim wheels but has it been confirmed that the only way to lower the nose would be to move the THS?
The THS was set very close to the end of its range (14 deg NU). The only clue given by the aircraft manual about elevator authority is that, they are powerfull, but it depends also on airspeed and THS settings: in case of a jammed THS above 8+ deg NU, the elevators control would be ok (say for a landing) if the aircraft airspeed is below 185 knots.
In AF447 case, the airspeed, once stalled, went far below 185 knots. Consequently it should be assumed that the elevator authority was not the main issue despite having the THS at 13 deg NU. Nonetheless, the airflow at one point into such a stall could also affect elevators control. Only Airbus could tell us if it is recoverable without moving the THS trim wheel.
Originally Posted by YRP
It seems that the crew made little or no ND inputs (apart from briefly shortly after the captain's return). So the THS position was not have been a factor. Whether there is enough elevator authority to recover is only a factor if they actually attempted it, no?
(I'm not making a statement on whether or not there was enough authority.)
Spot on.
This THS settings would be a non issue (beside an academic discussion about crew training to use it) if it would be confirmed, in the next interim report, that there was no real attempt to recover from this fully developed stall.
That was also my point from the last report. At any point before impact, did they really acknowledged that they were stalled? So far, it is leaked: NO.
If not, why this persistence in error? What really confused them?