Ramon Lopez/WASHINGTON DC
An aviation industry advisory group led by Boeing and Airbus Industrie says the US Federal Aviation Administration should continue to investigate cost-effective ways to enhance fuel tank safety on in-service and new airliners while ordering the changes for new aircraft designs.
Six months ago, the Aviation Rulemaking Advisory Committee (ARAC) was asked to come up with aircraft design improvements that would greatly reduce, if not eliminate, the possibility of fuel tank explosions, in the wake of the crash of a Trans World Airlines Boeing 747-100 shortly after take off from New York on 17 July, 1996. A fuel tank explosion is strongly suspected as the cause.
The ARAC's recommendations fall far short of those issued by the US National Transportation Safety Board (NTSB) which urges the FAA to order the costly installation of nitrogen-inerting systems in fuel tanks.
The FAA will now analyse and evaluate the ARAC report to determine its next course of action concerning flammable fuel-air mixtures. Meanwhile, the aviation agency continues to try and eliminate possible ignition sources in the fuel system through a series of airworthiness directives.
Only one member of the ARAC, Paul Hudson, the executive director of the Aviation Consumer Action Project (ACAP), opposed adoption of the ARAC report. He calls the recommendations "inadequate" and says cost estimates contained in the report were "inaccurate." ACAP says the FAA should immediately require airlines during summer months to not run air conditioning units and other heat producing equipment adjacent to centre fuel tanks. These emergency measures should stay in place until centre fuel tank inerting systems can be installed on commercial transports.
The FAA says fuel tank explosions represent less than 1% of the accidents that occur in commercial aviation. It estimates that future "events" over the next decade would cost $2 billion if no fuel system enhancements were made. The flammability reduction techniques studied by the ARAC would have a far greater economic impact (see box).
The FAA, which has already raised six airworthiness directives (ADs) related to fuel tanks on Boeing aircraft, has issued yet another, designed to reduce potential ignition sources in 747 centre-wing tanks. Carriers have two years to comply with the AD covering about 150 US-registered 747s.
The AD requires inspection of the tank for damaged, disbonded or incorrectly installed wiring and components.
Certain aircraft will require installation of a flame arrestor in the inlet line of the scavenge pumps or rework of the fuel quantity indication system.
Source: Flight International
