I've re-read the french and english statements.
If you get a stall warning, is there any reason to maintain nose up ?
At 2 h 10 min 51, the stall warning was triggered again. The thrust
levers were positioned in the TO/GA detent and the PF maintained nose-up
inputs. The recorded angle of attack, of around 6 degrees at the
triggering of the stall warning, continued to increase. The trimmable
horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about
1 minute and remained in the latter position until the end of the flight.
At 02:10:51 the plane was at 38,000 (having climbed 3000ft at up to
7000ft/min.) Thrust at 100%.
At 02:11:40 altitude was fl 350, angle of attack was 40 degrees,
vertical speed was -10,000/ft/min.
At 02:12:03 Thrust levels are at IDLE (55% power). WHY ?
At 02:13:32 Plane arives at fl 100.
So, in 2m42s, plane dropped from 38 to 10k feet: -10.3k feet/min
Or, in 1m52s, plane dropped from 35 to 10k feet: -13.4k feet/min.
Now, in the pretty graphic at end of document, we see that during the
descent, the plane went from a roughly 30° heading to a 270°
(clockwise). In my limited experience in primitive desktop computer
flight simulators, when you need to turn ASAP, you bank big time and use
elevators to do a "nose up" to get the plane to turn.
Is it possible that this is what happened here ? Crew realised there was
an inpenetrable wall of thunderstorm and attempted to U-turn but it was
too late and they were caught in a downdraft ?
If you're going to make a very steep turn, would you reduce thrust of
engines to reduce G forces/stress on airframe ?
Also, in a steep bank/turn, would high angle of attack be reported by
the FDR ?
BTW, it was 56 seconds betwene pilots declaring fl 100 and last
recording with a vertical speed of 10.9kft/min. This is thus consistent
with last recording happening at/near sea level.
10,000ft/min is roughly 184km/h.
13,400ft/min is roughly 247km/h.
Would such speeds be consistent with terminal velocity of an aircraft
Is it correct to state that with a nose up attitude, an aircraft would
never gain enough forward speed during freefall/stall to exit stall
condition and regain some lift ?
If making an emergency U turn, would pilots think about reducing engine
thrust to help reduce G forces on aircraft structure ? Could this be why
the engines were reduced from TO/GA thrust down to IDLE ?
And later, if the other pilot becomes pilot flying, he may have
forgotten about other pilot having reduced thrust for the turn and not
think about getting thurst back to 100% to escape stall condition.
Could the crew have tried to rise above a thunderstorm ASAP but in doing
so, reduced their airspeed AND still got caught in a downdraft which
caused a deep stall from which they never recovered ?
And finally, how much warning would a radar give of a thunderstorm up
ahead ? Minutes ? seconds ?
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