Pan Am Flight 214

Flight history

On December 8, 1963, Pan American 214, operating as Clipper Tradewind, departed Isla Verde International Airport in San Juan, Puerto Rico at 4:10pm Eastern Standard Time (EST) for a flight to Baltimore's Friendship Airport (now Baltimore-Washington International Thurgood Marshall Airport, or BWI), where 69 passengers disembarked.

At 8:24 p.m. EST, flight 214 departed for Philadelphia with 73 passengers and 8 crew members on board. Because of high winds in the area, the crew chose to wait in a holding pattern with five other airplanes rather than attempt to land in Philadelphia.

At 8:58 p.m. EST, while in the holding pattern, the aircraft was hit by lightning, which ignited fuel vapors in the No. 1 (left) reserve tank, causing an explosion that blew apart the outer portion of the jetliner's port wing. The crew of flight 214 managed to transmit a final message – "Mayday, mayday, mayday ... Clipper 214 out of control ... here we go" – before it crashed near Elkton, Maryland. All 81 people on board were killed.

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.

In response to the CAB's findings, the Federal Aviation Administration (FAA) ordered lightning discharge wicks (or static dischargers) to be installed on all commercial jets flying inside US airspace.

Volatile fuel vapor recommendation

On December 17, 1963, nine days after the crash of flight 214, Leon H. Tanguay, director of the Civil Aeronautics Board (CAB) Bureau of Safety, sent a letter to the FAA recommending several safety modifications as part of future aircraft design. One modification related specifically to volatile fuel vapors that can form inside of partly empty fuel tanks, which may be ignited by various potential ignition sources and cause an explosion. Mr Tanguay's letter suggested reducing the volatility of the fuel/air gas mixture by introducing an inert gas, or by using air circulation. Thirty-three years later a similar recommendation was issued by the NTSB (the CAB Bureau of Safety's successor) after the TWA Flight 800 Boeing 747 crash on July 17, 1996, with 230 fatalities, which was also determined to have been caused by the explosion of a volatile mixture inside a fuel tank.