Independent Air Flight 1851 is en route from Italy to the Dominican Republic and is scheduled to refuel on a Portuguese island. For some reason, a Boeing 707 crashes into a mountain just minutes before the airport. The international team of investigators finds no mechanical faults at all and is confused about the cause of the accident. Then the CVR reveals a cluster of errors that sealed the fate of the 144 passengers.

After losing both engines, a turboprop crashes in Papua New Guinea and investigators soon uncover a deadly flaw in an aircraft used around the world.