regarding somekind of fire, let me quote my own post three days ago :
i must say i finally do not believe all the fancy rumours.
i think they had somekind of an initially undetected smoldering fire in the electronic bay which disabled one system after another - starting with acars. after system failures began they decided to turn back to malaysia , using the heading mode .
just in the turn the fire melted through the structure resulting in a rapid decompression. the crew oxygen bottles, stored in the electronic bay, failed and the pilots were out of order. the decompression by itself also put off this fire.
the autopilot continued to work and stucked in the turn on a heading towards indian ocean where the plane continued until fuel exhaustion and then crashed.
any news on altitude changes etc are just false rumour from the malysian side.
it maybe that "simple".
i of course also can only guess but tell you should the thing will ever be resolved many of you will look as stupid as it can be with all the conspirancy theories. it makes perfectly no sense to hijack an aircraft just to fly it on the open ocean and crash without any word, suicide by pilot for life insurance is if far more easy by car against a tree than with this scenario , an unknown landing can be pretty sure excluded.
look at AF447 - what was speculated by "experts" - and who assumed they just stalled the thing and three pilots were not aware of it for several minutes.
this thread started good with useful info but quickly turned stupid, overhelmed by the usual "professional" entries, and should some people involved in the search or broadcasting serious reports on the incident read this all they surely will only have a laugh. i strongly recommend in future somekind of a system where you have to proof to the admin who you are before contributing in such discussions, otherwise this will ever be only a valve for people searching the thrill in wild speculations without any relationship to reality .