Salute!
O.K., back to the stab trim, with some air data contributed.
So I looked up as much as I could find and seems a very logical and straightforward trim implementation. Not as cosmic as the Airbus system we beat to death for AF447, but not entirely as clean as most think.
There
are air data inputs to the "elevator feel system" via the "feel and centering unit', so we might see a compound failure sequence. If the crew engaged AP around 2,000 feet, then the AP would hav a say in the elevator and stab control unless the humans did the override trick, huh? If the trim system had a problem, it would be compounded by the erroneous air data.
My point of interest focuses upon an event about 10 or 15 seconds prior to the sudden descent. Reminds me of the 737 rudder hardover way back. Those planes did not enter a shallow dive, and went straight in with velocities I used to see when dive bombing on steep angles - 500 to 600 feet per second rates. The Russian crash two years ago showed a damned near vertical dive and it was a 737. So high vertical velocity is not all that unusual in extreme loss of control crashes, regardless of cause.
At 00:41:49, the aircraft hit the runway approximately 120m from the threshold with a speed of over 600 km/hr and a nose down pitch exceeding 50 degrees.
So my interest is upon the trim system and crew efforts to control a plane with serious problems. I recall the Air Alaska debacle and those folks went beyond the envelope at the end fighting the jet. Hence, I am looking at the trim actualtor(s) and its inputs by crew and AP. Suppose a wire/signal was reversed? Suppose the jackscrew failed as it did on Air Alaska? Jezz wondering.
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