Turns out they descended down to 12,000' when they turned back....
Gee...who woulda thunk it?
Every trained pilot.
I stand by my original scenario; rapid depressurization and/or smoke/fire, the pilots turned back and descended, but then were overcome by the smoke/fumes, the airplane continued to fly on autopilot until it ran out of gas and it went into the sea. I doubt they will find it any time soon.
God bless the Aussies for trying, but I doubt there's any floating debris left by now, and even if they do find some, by now it's so far away from the point of impact, they may never find the airframe or the black (orange) boxes.
