Well, E1, your post doesn’t enlighten anything, it just preaches one-line rhetoric from a anti-media/skeptical standpoint. Now I don’t support the media, but the simple fact they reported it doesn’t make it wrong.
That said, here’s my understanding of the senario as gleaned from a composite of sources, and deciphered using an educated guess. By the way, Padeye, I am an Aeronautical Engineer, but that isn’t to say I know the specifics of a 767-300. So even the presence of an aircraft engineer doesn’t automatically create any better explanation ;).
First, the traditional understanding of an elevators control linkage to a pair of yokes doesn’t allow any possibility for this differential action. That theory of a pilot/copilot tug of war is about as logical as saying a driver and passenger in the family car fighting over the wheel could cause the front wheels to go in opposite directions. It just doesn’t make sense.
Now, the news stories seem to be claiming, with some slight discrepancies, that the pilot was away from the cockpit in the main cabin. The plane suddenly pitched forward, the pilot ran to the cockpit and began attempting to bring the plane to a climb. They theorize that the pilot and copilot were pushing and pulling in opposite directions. The radar and flight data say that the plane began a steep dive, then a short climb, followed by a decent and a roll to inverted. It accelerated, and the wings shreared off and the plane then crashed nose first into the sea. This is the theory as I understand it.
The basis that I’ve heard is a supposed uttering, and prayer from the copilot before the initial desent. A yell, and then a series of pleas for help from the pilot to the copilot as the plane is coming out of the desent and into the final plunge. The radar data indicates a controled, but erratic pattern of flight. The flight data indicates an intact plane, and the differential position of the aileron. So all this crap, and we get a movie of the week type senario. I suppose its possible, and I don’t see any other possibilities.
The problems with it is the arguement that the copilot is a happy, successful family man, with no apparent cause for this. The airlines, and defensive pilots are getting protective and claiming that this isn’t possible. The concept of a differential elevator is unheard of by most, and they claim the plane was not mechanically flawed at the time. So, is the elevator supposd to work that way, or do they mean the plane was not malfunctioning with the exception of the elevators?
The 50 pound differential in force sounds plausible, but if the explanation is to have an override in the case of a jammed yoke, why have the elevators move seperately? I understand having one yoke break loose so the other is controlable, but I can’t see any good coming from the elevators operating seperately. If this is the case in design, then Boeing may be open for critisism, but they need to clarify if this is a design feature or not. Otherwise, I can’t see any other explanations other thna the suicidal copilot.