Hello all...
I've been reading this thread since it's inception and have reached a point where my own curiosity compells me to ask a couple of questions... (Apologies if these questions have already been asked in this thread).
Before I do so, I will firmly point out that my association to aviation is purely as a hobby, but a very intense one, so my questions are from a lay person point of view, so I make no claims to any advanced knowledge of structures, accident investigation and so forth... Preamble over.
JBS, you frequently mention the 'sudden loud sound' on the CVR indicating a sudden explosive decompression. I even recall seeing a lineup of the comparison of those sounds for all of the accidents you believe are due to the cargo door opening in flight based on the sound of a DC-10 cargo door opening in flight. You also state that it they 'do not match the sound of a bomb' yet, I do not recall seeing the same comparison of the incidents based on the CVR sound of an actual 'bomb' that would show a definitive difference in the acoustic patterns from a confirmed bomb going off in the cargo hold. I am curious as to how the sound would differ if it were indeed a bomb that went off.
Also, in reading several of the accident reports, it is stated in them that the main deck floor beams of UA811 buckled downwards (albeit slightly for that accident) as well as with the Turkish DC-10 accident, the floor showed definitive signs of buckling downwards. Yet the reports for the Air India and Pan Am indicate that not only did the floor beams, but the seat legs and even forensic evidence on the passengers in the immediate area all show an
upward force having been exerted. I did not see that information in the TWA800 evidence, so I'm not including that in this question. I am curious as to how this discrepancy occurred if the intial event was the same for all accidents.
Again, I am not an aircraft structure expert nor do I know physics aside from the basics, but if there was an initial explosion in the aircraft (whether it be a bomb or a fuel tank explosion), there would obviously be a great deal of overpressure created internally due to the expansion of gases. Those gases will try to escape the aircraft any means possible using the weakest point in the structure (and I use that term only in a frame of reference as it is an opening to the outiside of the aircraft). That weakest point would be the cargo door in most cases -- blowing the door away from the aircraft as the floor buckles and full structural failure takes place. What would the difference in damage patterns be if the cargo door opening was the initial event, or if an explosion was the initial event creating the overpressure that may have caused the door to give way....
William