If a plane is going to burn, it's going to do it in pretty short order. Immeadiately after the accident, yes get as far away as you can, If within 30 minutes to an hour things haven't made big pretty fireworks, it's usually pretty safe. if there is a fuel smell around the wreckage, obviously don't smoke or give the fuel a reason to ignite.
Airplanes are really well insulated, if pieces are big enough to use as shelteryou are in luck
No matter what, don't move real far away from the wreckage, as it is far more visable from the air than the human figure. Your best bet on rescue is the resuers finding the wreckage.
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