Flight 370: A speculative scenario
From Flt 370: A Speculative Scenario by John Duncan:
...At 1:19AM the pilots signed off from Malaysian Air Traffic Control and passed into the airspace of Vietnamese air traffic control. Malaysia’s Acting Transport Minister Hishammuddin Hussein has said the ACARS system was deactivated even before the voice sign-off.
When Vietnamese ATC hadn’t heard from the plane by 1:30AM it asked other pilots in the area to attempt contact. One pilot about 30 minutes ahead did so and reported making a contact that contained a lot of static and “mumbling” from MH370, from someone that he took to be the co-pilot. That was the last signal heard from the aircraft.
I believe that a fire may well account for this---a fire perhaps started deliberately, as happened repeatedly on the Eithad flight, in or above the lavatories at the front of Business Class. Once in the ceiling space, the flames rendered inoperable various pieces of equipment and the electrical cabling that supplied them. Back-up equipment is of little use if connected to the same, disabled electrical circuits.
Such a fire would account for the series of equipment failures over a period of time, whereas a bomb or similar catastrophe could be expected to disable all at a stroke. Similarly, if hijackers had taken control of the aircraft, they could have been expected to shut down all systems more or less simultaneously, rather than pausing for irregular intervals before switching off the next system. If we accept that the ACARS system was rendered inoperable just prior to the 1:19AM sign-off to Air Traffic Control, the likelihood is that the pilots were as yet completely unaware of a fire raging above and behind them.
The pilots’ visual displays probably reported the ACARS failure, but such an alert would probably have been regarded, at least initially, as nothing critical, as radio-transmission failure is nothing extraordinary for the airline industry. The back-up system could be switched on and, in theory, all would be fine.
When flight computers started to fail it would have been a different matter. In trying to report the problem the pilots would have discovered that all their radio systems had gone down. At this time, there would also have been a bedlam of erupting cockpit alarms, swamping the harried pilots with an overload of information...
James Fallows supports the mechanical failure theory, encompassing the fire scenario that would necessarily include a fire deliberately set by the likely suspect/suspects, Islamic fanatics:
No theory of the plane's disappearance makes sense. But I've mentioned several times that I thought the "Chris Goodfellow scenario" required few logical leaps than most. Goodfellow, a Canadian who now lives in Florida, has hypothesized the following sequence: a sudden inflight emergency, followed by a turn back toward airports in Malaysia, followed by a still-unexplained incapacitation of the crew, and a still-unexplained flight out over the ocean.
If you would like to see an argued-out (rather than merely speculative) version of a contrary hypothesis, check out this on Leeham News and Comment. The item is based on an interview with Greg Feith, a former NTSB investigator, who argues (a) that the wreckage might well never be found, and (b) that the most likely scenarios, in his view, involve one of the pilots deliberately bringing the plane down...