According to wikipedia, "It was later discovered that as many as 14 other passengers also survived the initial fall from the disintegrated plane but were unable to seek help and died while awaiting rescue."
"Herzog was inspired to make this film as he narrowly avoided taking the same flight while he was location scouting for Aguirre, Wrath of God. His reservation was canceled due to a last minute change in itinerary."
http://en.wikipedia.org/wiki/LANSA_Flight_508