We'll see, Innmarsat left a little weasel room in their statement.
Some of the Malaysian PM's statement was to give the families an impramateur to go home and begin the grieving process of the loss of their loved ones. They can go home if they chose, without gilt if that makes sense.
Now saying the aircraft turned left and descended to at least 12000 feet -
Inmarsat CEO also said that they are confident the engine data came from that specific airplane. Wish I knew that it was transmitted outside of the supposedly disabled Satcom/ACARS.
It is also SOP in many theaters of operation where long range nav is used to turn off of your airway or track and descend after obtaining a lateral offset of a predefined distance. This is the procedure for loss of pressurization or engine out drift down. You would get a clearance to do so if you had Comms, if not, you would still execute the offset and descent while broadcasting on common frequencies, all lights on, etc. this is all to get clear of traffic before descending through altitudes in use.
Might indicate a loss of pressurization, fire, uncontained engine failure, etc. I hope they follow up on this and quit chasing "gooses".