identify the exact mechanics of the fuel ignition, concluding that lightning had ignited vapors through an as-yet unknown pathway. The board said, "It is felt that the current state of the art does not permit an extension of test results to unqualified conclusions of all aspects of natural lightning effects. The need for additional research is recognized and additional programming is planned." Legacy The crash of Pan Am Flight 214 called attention to previously unknown risks to aircraft from lightning strikes. One month after the crash, the FAA formed a technical committee on lightning protection for fuel systems, including experts from the FAA, CAB, other government agencies and lightning experts. The committee agreed to conduct both long-range and short-range studies of the impact of lightning on aircraft fuel systems, and potential measures to defeat such hazards. In 1967, the FAA updated airworthiness standards for transport-category airplanes with requirements that fuel systems must be designed to prevent the ignition of fuel vapor within the system by lightning strikes, and published guidance related to that requirement. Additional requirements to protect the aircraft from lightning were enacted in 1970. Many aircraft-design improvements emerged as a result of the new guidelines and regulations. New regulations mandated the electrical bonding between the surface of the aircraft and any items that are installed on the surface of the wings near the tanks, such as fuel filler caps, drain valves, and access panels. Fuel-vent flame arrestors were added to aircraft to detect and discharge fire suppressant to extinguish fuel vapors that ignite at fuel-vent outlets. Passive flame arrestors were also added to internal vent pipes to help extinguish any flames that make it past the first stage arrestors. The thickness of the aluminum surfaces of aircraft wings was increased to reduce the potential for lightning to completely melt through a wing surface into the wing's internal components. See also LANSA Flight 508 – Another accident caused by a lightning strike TWA Flight 800 – Aircraft accident caused by ignition of fuel vapors References External links A Pan American promotional film that features Clipper Tradewind (N709PA) A picture of the aircraft involved in the accident (archived from the original on November 4, 2012) Another photograph of the aircraft involved Accidents and incidents involving the Boeing 707 Airliner accidents and incidents caused by lightning strikes Airliner accidents and incidents in Maryland Airliner accidents and incidents involving in-flight explosions Aviation