David Learmount / London
The Association of European Airlines (AEA) and Airbus have accused the US Federal Aviation Administration of disregarding accepted cost/benefit criteria in its latest notice of proposed rulemaking (NPRM) on fuel-tank safety.
The FAA wants to go beyond the improvements already adopted since the 1996 Trans World Airlines Boeing 747 mid-air explosion, caused by the ignition of the fuel/air vapour mixture in its empty centre-wing fuel tank, and the comment period for its new proposals has just ended.
The additional measures proposed, described as “flammability reduction” methods and including fuel-tank inerting, would “protect the public from calamities which...are otherwise virtually certain to occur”, says the FAA, and they would apply to in-service aircraft as well as new-build airframes.
However, vigorous objections to the NPRM have been filed separately by the AEA and by Airbus. They claim that, in its proposal document, the FAA has overstated the risk of fuel tank explosion by a factor of five and the cost/benefit ratio of the proposed new measures by a factor of 28, and they suggest that statistics show adoption of the measures would risk killing more fuel-tank maintenance personnel by asphyxiation than it might save in passenger lives.
Airbus says the fuel tank explosions quoted by the FAA as the rationale for its rule involved a 747, two 737s and a 727 whose centre-wing fuel tank was ignited by a terrorist bomb, but none involved Airbus types. The manufacturer submits that Airbus fuel- tank safety design had originally incorporated the improvements ordered after the TWA flight 800 explosion. Airbus’s 99-page comment also challenges the validity of almost every assumption or statistical projection in the FAA’s 84-page NPRM.
The European Aviation Safety Agency has not proposed a rule that mirrors the latest FAA fuel-tank safety NPRM, but it has harmonised its fuel-tank safety regulations to incorporate the FAA’s post-TWA 800 design improvements.
The AEA says it objects to the FAA measures on the grounds that, even though its 30 member carriers would not be directly affected by any US airworthiness directive, the potential value of non-modified European-registered aircraft that could be sold or leased into the US market would be reduced.
The AEA alleges that the NPRM “appears to be driven by National Transportation Safety Board statements and public opinion”.
Source: Flight International
