Investigation
The Civil Aeronautics Board (CAB) investigated the accident, and issued the following Probable Cause statement on March 3, 1965:
Probable Cause: Lightning-induced ignition of the fuel/air mixture in the no. 1 reserve fuel tank with resultant explosive disintegration of the left outer wing and loss of control.
It is now thought that the lightning strike that caused the ignition was a rare positive lightning bolt.
Read more about this topic: Pan Am Flight 214