This article needs an improved plot summary. (November 2015)
Pilot Jack Savage (Rod Taylor) is suspected of drinking and causing an airliner crash that kills 53 people and leaves only a single survivor, Martha Webster (Susanne Pleshette), a flight attendant. The captain's wartime buddy, airline executive Sam C. McBane (Glenn Ford), is convinced of his friend's innocence and investigates doggedly. Flashbacks deal with both Jack's past and Sam meeting him, plus others they used to know.
Eventually, a test flight recreates the events of the ill-fated flight. They find that the crash was caused by a fateful malfunction of the aircraft's warning systems.
What system malfunctioned and caused the crash?
Warning system