Safety Board Calls For Fuel Tank Safety

Aviation Daily: ARAC Is Advised Fuel Tank Inerting Not Cost-Effective

By Aviation Daily Staff

09-Aug-2001 8:39 AM U.S. EDT

The executive committee of the Aviation Rulemaking Advisory Committee was told yesterday that fuel tank inerting to prevent another TWA 800 accident is too expensive to be cost-effective.

The ARAC report is now under consideration by the executive committee, which may accept the findings or send the report back for more study, according to FAA. Airlines had opposed inerting, although NTSB had recommended inerting to eliminate "potentially explosive vapors, so that even if an ignition source exists, it will not by itself lead to a catastrophic accident."

Carol Carmody, acting NTSB chairman, expressed "disappointment that their cost-benefit analysis leads them not to recommend inerting systems. We question the factual basis for the cost-benefit analysis presented in the report." She is "pleased that the ARAC executive committee appears to share our concerns and has requested further clarification of that analysis."

Carmody pointed to the recent destruction of a Boeing 737 in Thailand that, she said, "shows that center fuel tank explosions continue to occur, and likely will occur again in the future....The safety board strongly believes that near-term measures to eliminate flammable fuel tank vapors are necessary and prudent."

The working group concluded that inerting was not technically feasible although Litton Life Support, a division of Litton, agreed with the safety board that inerting "can eliminate risk associated with the identified sources of fuel ignition" and is "technically feasible." The Litton report was presented in October 1997.

ARAC was directed to look into the issue on a "fast-track basis" in 1997. The FAA Tech Center bought a 747SP to test both ground-based and aircraft-based fuel tank inerting.

An Air Transport Association official said he believes inerting "would have been a hugely complex effort requiring modifications of all the airports and all the airplanes." Foreign airports also would have to install inerting systems, he said.

The proposal was for nitrogen to be used as the inerting gas, but extensive use of nitrogen would add risk to employees and passengers.

Industry preference is to continue to focus on fuel tank design standards and the elimination of potential ignition sources, as FAA has proposed. More than 40 airworthiness directives have been issued on fuel tank safety.

Aviation Daily is an Aviation Week newsletter. Click here to try a FREE subscription.