Biohazard said:the likely hood of that actually happening is ridiculous
Or fairly common if you actually look at the reports from a number of crashes
It happens on a regular basis, the passport is light enough but fire resistant enough that it can survive being blown out of the aircraft by an explosion.
There are dozens of crashes where there has been a major impact followed by a bad fire and yet passports have been found relatively intact (often a bit bit singed but still readable).