He was rejected by his wife, and possibly by his mistress (got a call from someone just before the flight). His friend says he didn't seem like himself, and shouldn't have been flying.
His retirement fund may have been heavily invested in Malaysia Airlines stock, which had declined about 90 percent in the past few years (or so I hear). Business Week says:
"...Long before one of its Boeing (BA) jumbo jets vanished into the tropical darkness, Malaysia Airlines was struggling to find its financial footing. The carrier has lost money for more than three years, beset by high costs, a proliferation of unprofitable new flying in its network, and two low-cost rivals at its home airport in Kuala Lumpur..."
According to the same Business Week article, Malaysia Airlines has lost more than 1.2 billion in the last three years. The captain was concerned about the viability of his company (bankruptcy, losing his job, jeopardizing his retirement plans). This alone wasn't enough to make him snap, but it was a contributing factor.
Let's analyze this scenario. He could have taken out the copilot with one blow from the cockpit crash ax, timed for right after the sign-off call to Malaysian ATC.
He turned off course, turned off the emitting ADS-B and transponder, and maybe the ACARS (but didn't get out of his seat to pull the circuit breakers for the SATCOM). He ran up the cabin to 25,000 feet or more manually, and made a PA announcement of a mechanical problem as the oxygen masks deployed automatically at about 14,000 feet cabin altitude. The flight attendants had the passengers stay in their seats, on oxygen. The passengers couldn't leave their seats or they'd pass out almost immediately (if they didn't already as he ran up the cabin altitude). After 20 minutes max, the cabin oxygen generators exhausted, and the last of the passengers passed out and then died. The flight attendants either died with a mask on or used the walkaround bottles to try to survive, but even this was not enough if the cabin was very high, especially if they were exerting themselves by moving around the cabin.
Everyone but the Captain could have been dead or near death by 30 minutes after his initial off-course maneuvering, even without running the cabin up to extremes, above 30,000 feet.
After a few more turns, possibly intending to confuse the ATC primary and military radars, he set the course for the south and eventually passed out himself from too high of a cabin altitude with oxygen, or simply removed his own oxygen and went to sleep. Or maybe he stayed awake for several hours, but I doubt it.
The airplane flew on autopilot until it ran out of fuel, then plunged into the ocean.
Game over.
I think they should run this (last part) scenario in the simulator to see what the attitude of the airplane was at impact. The airplane probably descended slowly after the first engine flamed out, maintaining course. It didn't crash until the second engine flamed out, but I think the generators would have dropped off line and the autopilot would have disconnected, even though there might have been windmilling hydraulics that otherwise could have enabled the flight controls. I doubt it impacted in a landing attitude, since the wreckage would have been more intact and there would have been quite a bit of floating debris - and if the airplane had floated for a time the ELT's would have been picked up by satellite. Once they submerged, they soon quit working, and only the ULB is still emitting -- and only for another couple of weeks.
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Business Week: Malaysia Airlines Has Been Missing Profits for Years
http://www.businessweek.com/articles/2014-03-24/malaysia-airlines-was-in-trouble-long-before-flight-370
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Time of Useful Consciousness (no supplemental oxygen):
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15,000 feet: 30 minutes or more
18,000 feet: 20-30 minutes
22,000 feet: 5-10 minutes
25,000 feet: 3-5 minutes
28,000 feet: 2.5-3 minutes
30,000 feet: 1-3 minutes
35,000 feet: 30-60 seconds
40,000 feet: 15-20 seconds
45,000 feet: 9-15 seconds
http://www.theairlinepilots.com/medical/decompressionandhypoxia.htm
Your scenario is right in the ballpark according to the facts as we are finding them out to be.
The Malaysian military is now admitting that it had the flight on radar from 1:19 until 2:40 — a major reversal of their original denial.
It took two minutes to turn it around.
It went up to 45,000 for 23 minutes then dropped precipitously to 12,000ft and headed northwest up to waypoint Igrex, a busy flight corridor, that he was on until probably 2:40 when Malaysian radar lost contact.
When Inmarsat paints it at 3:11, it is no longer on that northwest heading but heading south.
Two questions:
1] How long did he remain at 12,000ft — until 2:40 or all the way south and why???
2] Did he drop to 12,000ft so that at some point west of Indonesia he could get the door open and bail out to be picked up by the person he got an illegal cell phone call from just before the flight?
Most of us pilots in my sphere of influence do not believe there was any climbing and certainly no rapid descent. It would not have served any purpose unless there was a struggle involved. Remember the transponder is off and Malaysian military radar can not accurately know for certain altitude from the distance all this was suppose to occur. Most importantly, in any scenario, who knows, who cares about the climb and descent. Mostly a sideshow element.
It never occurred to me to think about before this incident, but yes it would very simple to kill off passengers and most crewmembers. Again absolutely no reason to climb to accomplish. Certainly one would not descend rapidly if that is what you are trying to accomplish. 777 chemical oxygen generators last 22 minutes. HOWEVER that 22 minutes takes into account the plane is descending. IF the plane does NOT descend, the oxygen lasts less than the 22 minutes. How long is anyones guess.
The Captain would have been acutely aware of the Helios flight 522 crash where a B737 flew for almost 2 hours with the pilots and passengers dead. HOWEVER, an off duty cabin crewmember survived the whole period using the portable oxygen bottles. He made acess to the cockpit, but did not know how to establish communication and of course how to fly the plane. He made a heroic effort but ended up spinning it end.
ADS-B is part of the transponder system. You turn off transponder, ADS-B is turned off. Again has no meaning.Turning off ACARS much more simple than many make it out to be.
Autopilot automatically disconnects when an engine fails due to many reasons. All very simple, all very logical to the system. IF pilot still alive, he would just re connect. If he is dead, the plane plummets from that position. The failed engine provides too much drag and aerodynamics are interrupted.
Pilot suicide has as much possibility as any other theory right now. I hope you understand that most of in the pilot community, again in my sphere of influence see alot of problems with that theory. Mostly because we spend our whole career protecting what we consider to be the most valuable commodity on board that plane. That would be the passengers. Also, we have established relationship with many many of the cabin crewmembers. In and off the plane, on the road, we would do anything to make sure they are protected and safe. Not in our psych to kill them. Yes there have been two recent examples, but it is hard to accept.