Originally Posted by
MountainBear
Actually, an electrical fire would explain all of those things. For one, if there is an electrical fire (or a suspect electrical fire) turning off power to the affected system is exactly the right thing to do. It also could explain the flight path deviations because the an electrical fire in the cabin would not affect the engines but could affect the ability to control the plane.
FAA: Some Boeing 777s need fixes in case of fires
Batteries are NOT the only thing that can cause an electrical fire. The in- flight entertainment system can cause them too, see article above.
In that case there would have been an emergency call or at least a brief 7700 squawk. Even Swiss Air managed to talk to the controllers even as molten metal was raining in the cockpit. The time 1:07 for the ACARS log off was before the aircraft was handed over to Vietnam. So the nice good night from the pilot was as they were fighting a fire?