Originally Posted by
tubby linton
At 4:31 in the video in post 362 is the item in the background the jack screw for the stab?
This should be a pic of the jack screw on a 737. I dont know how the 767 one looks, but the screw in this picture and the triangular bracket going to the tail plane is very similar to the screw and bracket in the video at about 4.30. If so, then the jack screw in the video seems to be at about 2/3 nose up position.
But, can this be possible? If the jack screw is almost full nose up, how come the airplane plunged like it did? Even if we suppose the trim was running towards nose up at the time of impact, how many seconds would it need to run to this apparent position from lets say a neutral position? Would it be possible at all in the available 18 to 20 sec to first get the airplane to start plunging where the jack screw obviously cant have been in almost full nose up position, and then at some time before impact start running in the nose up direction and have time to reach the position it seems to have had at impact? And another question, considering the very high indicated airspeed the aircraft had at impact, would an almost full nose up trim position be compatible with wings AoA below a value where generated lift wouldnt tear the wings off of the aircraft?
What would the AoA be for the airspeed the aircraft is assumed to have had at impact and at the same time generating say 3G? I believe somewhere between say 5 to 9 degrees AoA at say 400 knots at low altitude would produce so much lift that the wings would tear off?
So, could it be possible that the tail plane was not in the postion that the screw jack is indicating, ie that the screw jack had broken loose in one end before impact?