The FAA is amending certain airworthiness regulations for transport category airplanes to require fuel tank designs that prevent a fuel tank explosion caused by the propagation of flames, from external fires, through the fuel tank vents. This final rule requires a delay of two minutes and thirty seconds between exposure of external fuel tank vents to ignition sources and explosions caused by propagation of flames into the fuel tank, thus increasing the time available for passenger evacuation and emergency response. These amendments apply to applications for new type certificates and certain applications for amended or supplemental type certificates. The amendments also require certain airplanes produced in the future and operated by air carriers to meet the new standards.