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Old 3rd Dec 2013, 08:57
  #348 (permalink)  
DOVES

DOVE
 
Join Date: Oct 2003
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A SPIN

… when a GA was initiated, either due to the strong pitch up moment caused by the engines and the vertical upward component of traction or 'apparent lift', it was not easy, or even impossible, to stop the rapid attitude increase if not by trimming down or reducing engine thrust. …

So with:
-High-pitch attitude
-Slow/decreasing-speed, with AOA approaching stall

Whippersnapper http://www.pprune.org/tech-log/43116...ml#post6014975
…the elevator feel shift centre position moves and its hydraulic pressure increases. This is combined with the speed trim system trimming (aircraft) nose down. The combination is meant to emulate the old fashioned "stick pusher" on older aircraft with hydraulic controls.
My guess is that the speed trim is inhibited as the stick shaker is activated (perhaps as an assumption a trim system malfunction is the reason for the high AOA), but if AOA is further increased to the point that the stall is imminent, the speed trim is reactivated to trim nose down.

BOAC :http://www.pprune.org/tech-log/43116...ml#post6011471
…We always found that at 1kt/sec you did not have enough back stick to keep the nose high enough to reach anything other than a gentle 'mush out', and never got to stall speed. I assumed the point of it was to try to ensure there were no 'nasty' asymmetries waiting to bite…

It's just a little rotation (some rudder, some aileron, different thrust on the engines) on the yaw-axis to cause a spin.

OR
When the speed became so low, with AOA approaching stall the STS activated commanding automatically the pitch trim towards AND, the elevator feel pushing, and at least one CM distracted to communicate with TWR for 16 sec…
With so little altitude to even try a recovery..
The fate was written

Last edited by DOVES; 3rd Dec 2013 at 16:52.
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