Buffalo Q400 crash
bod43 wrote:
On 13 May, 12:57, Robert Moore wrote:
James Robinson *wrote
The drop in airspeed was unnoticed, and the stall seemed
to catch them completely by surprise.
I wonder what the stall warning was doing all of this time?
Bob Moore
It appears that it was the stall warning (stick shaker) that the
captain (pilot flying) reacted to.
The reaction was to immediately pull back pretty hard
quickly precipitating an actual stall. 80% power was also
selected immediately. The stick was held back pretty much
until impact.
There was a theory on one of the other pilot forums that the captain
might have done all of his stall training when the aircraft was under
manual control, untrimmed, with the throttles cut until the speed dropped
below stall speed. He might have gotten used to having some backpressure
on the control column to avoid altitude loss under those conditions.
He might never have experienced stall training where the AP had ratcheted
the pitch trim toward its maximum, and was caught by surprise with the
sudden pitch up when the AP kicked off.
The FDR shows his immediate reaction to the stick shaker was to apply 20
lbs backpressure, which he immediately let go of as the aircraft pitched
up. He never pushed on the control column, however the wild
left/right/left/right rolls pretty well made controlling pitch a moot
point.
One curious thing about the FDR data is that it shows 20/25 lbs
backpressure on the control columns on both sides immediately after the
stick shaker fired, with the force on the #2 side the higher of the two.
Did both the captain and FO react by pulling up? Did the FO yank on the
control column at the worst time to steady herself because her seat moved
on the track? Very strange.
Not sure I buy it, but an interesting theory about stall training.
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