Ok, I'll jump in.. I don't normally speculate (I'm a heavy Captain for a US airline with a lot of overwater experience in an ac like the 777), but I will add this, with CPDLC, HF, VHF, ACARS and SATCOM, I'll find some way to get a message out under duress.. especially CPDLC, for it's a couple of key strokes.. would take me.. 5 seconds, tops.
- Chances of complete loss of comm on the 777, very, very slim...
- Bomb explosion we would have found the pieces long ago...
- I don't like structural failure theory cause it would have led to disintegration of airplane and then aircraft pieces would have already been found...
my theories fall into these two areas:
1. Hi-jack (terrorism from outside or crew)
2. Hypoxia event leading to incapacitation of all life on board.. (has happened in the past)
I can see why you are arguing against either a complete systems failure or a bomb. I realise no-one has the answers, least of all me, I just have more questions. However...
If 1. Hi-jack is correct then why no distress communication from the pilot or indeed anyone at all on board during the take-over phase of the hi-jacking? If it was a hi-jack we have to believe it was sudden, total and prevented all communications capabilities of all passengers and crew. Even if part of the crew were responsible, would not the remainder of the crew or passengers have become aware at some stage that something was amiss and had time to send out a distress call of some kind before they could be stopped?
If 2. Hypoxia is correct then why did all means of communication manual
or automated cease so abruptly? That seems to indicate either deliberate intervention by an experienced crew member or an immediate catastrophic event causing all comms on the aircraft to fail simultaneously at the last known point of communication. But then how come it either continued to fly, or else just as in your bomb scenario, why has no wreckage been found by 5 days of SAR?
It seems to me that we are left with one indicator of a catastrophic event at the last known civilian reference point (sudden cessation of all communication) but other indicators of continued flight (military primary radar possibly tracking to west, no explosion "flash" picked up on military satellites (as I understand it) and lack of debris in area that has been searched for 5 days now).