Originally Posted by
Austin787
Deliberate action, absolutely. If there is a fire onboard the aircraft (which I think most likely happened to MH370), you want the pilots to take deliberate action - turn the plane towards the nearest suitable airport and land ASAP. In MH370, the pilots believed turning back to Malaysia was the best option, which would explain the sharp turnaround after the sign off from Malaysian ATC.
If it was an onboard fire I blame the Li-Ion batteries at the cargo bay.