BrisBoy C: The aircraft suffered a major problem. The pilots started working through the checklists and decided on an air return
I have to agree with you on this one. There could have been a return in the secondary flight plan and this was activated. Could well explain the points being overflown. The plan then had a discontinuity and so the aircraft maintains the last heading. Aircraft continues until eventually runs out of fuel.
There have been a few instances of aircraft landing after the pilots ejected from mil aircraft.
Taken from the aviationist ..During a training mission from Malmstrom Air Force Base, on Feb. 2, 1970, his F-106 entered an uncontrollable flat spin forcing him to eject. Unexpectedly, the aircraft recovered on its own and made a gentle belly landing and skidding for a few hundred yards on a field near Big Sandy, Montana, covered by some inches of snow...The aircraft, returned to active service after the mishap.
The Aviationist » The weird story of a U.S. jet that recovered from flat spin and made a gentle landing. Unpiloted
Sure it was a fighter and landed on a flat field covered in a few inches of snow, it still survived enough to be serviceable again.
The 777 is built like a tank just look at the video of the San Fran crash.
The plane could quite possible have 'landed' on the water and now sunk. If this happened then the black boxes would not be activated, unless they are activated if immersed in water.
Probably why all the searching is happening where it is. The last heading / track can be deduced from the pings and a plot drawn. The only problem is what the drift was at the height they were flying.
Everything could be at the bottom of the ocean. The water pressure would most likely crush parts of the fuselage but it is that pressure that will stop anything floating up. Eventually due to ocean currents items will be washed up but hundreds of miles away.
Suicide / hijacking does not add up any more. There is no reason to suspect 2 professional aviators. Hijacking well forget it, a call would have been made somehow, even by the cabin crew activating ELT's.
Lithium Fire that is the number 1 suspect. Just how many Lithium batteries were on board. Why the secret!