Came across this plane crash at about 20,4 in Searing Gorge, above the Twilight Geomancers, however, you can't get to it that way - you have to come across the mountains to the east, starting in Dun Morogh.There's nothing there, no NPCs or anything. Obviously just eye candy, as a flight-path is overhead.
If you then travel to the west of this area you can find a large un-developed section of bare mountainside. There is an invisible wall some of the way preventing you from entering, but you could probably skip around it, if you were so inclined.
