Originally Posted by
lomapaseo
Remember you are probably getting closer to the cows or even worse, mountain tops. So don't squander your air speed and altitude by stretching out unlikely attempts at restarts.
I have seen some analysis (at lower altitude) where the only chance was to push the nose over and dive. Of course all engine restart envelopes are not the same if only because there are other trades to consider.
BA 009 Jakarta incident springs to mind where the crew had no idea why all 4 engines had failed.
"
Owing to the high Indonesian mountains on the south coast of the island of Java, an altitude of at least 11,500 feet (3,500 m) was required to cross the coast safely. The crew decided that if the aircraft was unable to maintain altitude by the time they reached 12,000 feet (3,700 m) they would turn back out to sea and attempt to ditch into the Indian Ocean. The crew began engine restart drills, despite being well outside the recommended maximum engine in-flight start envelope altitude of 28,000 feet (8,500 m). The restart attempts failed."
"At 13,500 feet (4,100 m), the crew was approaching the altitude at which they would have to turn over the ocean and attempt a risky ditching. Although there were guidelines for the water landing procedure, no one had ever tried it in a Boeing 747. As they performed the engine restart procedure, engine number four finally started,"
BA 009