Here's the key description of the a/c's movements from the ATSB Media Conference:
Quote:
While the full interpretation and analysis of the recorded data will take some time, preliminary review of the data indicates that the aircraft was cruising at 37,000 feet, when the aircraft initiated a climb of about 200 feet, before returning back to 37,000 feet. About 1 minute later, the aircraft pitched nose-down, to a maximum pitch angle of about 8.4 degrees, and descended about 650 feet in about 20 seconds, before returning to the cruising level. About 70 seconds after returning to 37,000 feet there was a further nose-down pitch, to a maximum pitch angle of about 3.5 degrees, and the aircraft descended about 400 feet in about 16 seconds, before returning once again to the cruising level.
|
Given the concentration of injury at the rear of the a/c, it would seem logical to speculate that the initial elevator movement which caused the 200 ft climb could have been violent enough to throw those at the rear of the plane into the cabin ceiling, and throwing them to the floor when what was probably an equal and opposite elevator movement returned the a/c to FL370.
Whilst the 8.4 degree pitch down and the 650 foot descent is very severe, we aren't told how quickly the a/c returned to FL370 and it seems to me that the second movement sequence would not have involved the tail of the a/c moving down then up in a way that would throw unrestrained people and objects into the ceiling for three to four seconds and then into the floor.
Similarly the third movement sequence of a pitch down of 3.5 degrees followed by a pitch up seems to me unlikely to account for the physical reaction of people and objects that has been described.
So, just based on logic and physics, the only one of the three movement sequences that has involved a sudden tail down followed by a tail up was the initial 200ft climb/descent sequence. It will be interesting to find out the pitch angles involved in this movement sequence but I would surmise they involved close to full amplitude elevator deflection and thefore extreme pitch and therefore extreme forces of the kind that would account for the movement of unrestrained people and objects.
Do others agree with this analysis or is it too simplistic?
Of course it doesn't explain what caused the sudden elevator movement in the first place but that is plainly a critical part of the investigation in case it reveals a latent defect in the avionics programming similar to that which was revealed with the MAS B777ER incident out of Perth a couple of years back.