flight 836 with 194 onboard was flying over the south china sea bound for shanghai when both engines went out. the sudden loss of power at 39,000 feet as the jetliner passed through bad weather. within seconds, the aircraft dropped nearly 13,000 feet. the pilot has to basically put the plane that s now lost power in its engines in a dive. and that wind going through those engines spins the turbines and helps the pilots get a relight. but even with a relight, getting your engines actually going again, fuel is burning, you have to be able to sustain those engines. so it s a really tricky maneuver. reporter: singapore airlines said the problem started about 3 1/2 hours after departing from singapore. they say one engine regained power while pilots worked on the second. that is something they re trained to do. and in all cases on all planes there is a point at which the manuals say, don t try any more diving restarts.