Simple, yet the most plausible. Forget about those fanciful theories being bandied about,from pilot suicide to cyber hacking of its computers to hijacking then landing in Taliban Pakistan and other conspiracy theories.
The account provided by Chris Goodfellow, an experienced pilot (see link below) suggested some mishaps on board, turning back and finding the best landing place and flight maneuverings (including to put out the fire), made a lot of sense and it is strongly tied up with evidence collected so far, technical and sightings by people on the ground.
Malaysian and Thai military radars and the plane’s ‘pings’ picked up by an independent satellite seemed to have place MH370’s flight path towards the Indian Ocean. It is unlikely that it had flown north, otherwise the radars of several countries there would have pick up the plane. Thus, the ‘southern corridor’ in the Indian Ocean was the most likely area where the plane was and subsequently crashed due to fuel ran out.
There were two sightings of what may have been the plane. One off the east coast of Malaysia, by an oil rig worker off the coast of South Vietnam, of what may have been a plane on fire and then by a fisherman in a village on the east coast, near Kota Bahru, Kelantan. These were consistent with the last of the readings – Aircraft Communications Addressing and Reporting System (ACAR), transponder (see “How do you track a plane?”), militaries and the satellites (the ‘pings’ being the last).
It is conceivable, therefore, there was fire on board, the pilot had tried to put out the fire, had turned back and headed for the nearest, safest landing spot, Langkawi Island, (northwest, near Penang, see Google map), as the author had suggested.
Fire in an aircraft demands one thing: Get the machine on the ground as soon as possible.
The plane turing back, maneuverings, deliberate as we have now concluded, the flight paths, all these were consistent with what the author had suggested – a plane in trouble, the pilot turned back, tried to fix it, lost electronic communication, could not reach Langkawi, veered off course and headed towards the South Indian Ocean.
The loss of transponders and communications makes perfect sense in a fire.
I would bet my bottom dollar that the wreckage would eventually be found somewhere in the Indian Ocean, in one of the possible places that they are now searching. One does not have to look too far, as usually the least expected is where it is.