Sorry to intrude into such a knowledgeable (or wannabe knowledgeable) group. I've been lurking to learn, and test a few theories of my own (i.e. catastrophic electrical fire/failure, followed by loss of pressure in cabin). To that, I've paid attention to those that note the shut down of ACARS first. So to that, I have a question that I don't believe has been addressed to the pros here yet.
Much of the suspicion that is being cast on the cockpit crew at this moment stems from a Malaysian authority's (is that an oxymoron??) insistence that ACARS was deliberately shut down over 10 minutes before final communications and transponders failure/turned off. On one hand, I have to agree with one prior comment that until I saw a log off log, I'm not sure we can believe much from Malaysian authorities, or the press. Lousy track record and all that jazz... But for now, let's assume there was a formal log off.
I've heard pilots over the years mention that the ability to disable transponders is an important safety feature while in flight. But I don't hear much about the the same for ACARS, or the limited access you have to ACARS thru MCDUs on the pedestal. I have gone back to read older threads here about the value of ACARS, not to mention the insecure communications that are part and parcel of the system.
So two questions:
1: Is there a reason a pilot would voluntarily log off of ACARS?
2: Doesn't ACARS, if it loses VHF communications for a gap of time, request a voice log on at that time, forcing it to SATCOM? In which case, does it go thru it's own "log off" sequence? And isn't it possible that the crew would not notice if they were not depending upon it for weather (great weather that night), or confirming general log in events not needed until later?
The only reason I ask was that I tried some self education on ACARS and any anomalies - or why a crew may voluntary go thru a log off procedure in flight. And what I landed on was Canada's TSB report on the Swiss Air 111 crash back in 1998.
Transportation Safety Board of Canada - AVIATION REPORTS - 1998 - A98H0003
It probably taught me enough to know I'm even more a clueless novice. So I thought I would put it to the forum for further education.
Personally, can't see much reason for terrorism or suicide. The political views held by Capt Shah are about as far away from militant actions and fundamentalists as possible (pro Demoracy/anti-corruption). Nor would disgruntled attitudes towards Malaysian politics INRE the jailed opposition leader be much of a reason for killing what is a majority of innocent Chinese citizens.
Most importantly, I'd certainly hate to think that pilots' political views have to be considered for employment, or used to destroy reputations as a scapegoat. That's a dangerous precedent.
INRE suicide, according to media accounts, he and his wife had been separated for some time, but were sharing a home. So I can't see existing marital problems as suddenly being a reason for suicide.
All theories around deliberate acts, targeting the crew, start with ACARS... *if* it was deliberately shut down. Thus my questions. My thanks for your explanations, and I'll go back to lurking now.