Making fuel-vapour in airliner fuel tanks explosion-proof would require "a major change in design concept", says the US Federal Aviation Administration, replying to US National Transportation Safety Board (NTSB) recommendations following the July 1996 Trans World Airlines Boeing 747-100 crash.

The FAA, however, says that it will publish the NTSB's recommendations and provide a 90-day public-comment period "-to solicit additional information regarding effectiveness and practicality".

The FAA confirms that the 747 broke up after an explosion of the almost-empty centre fuel-tank. Evidence of an ignition source is still sought, but the FAA says that there is no sign of bomb or missile damage.

The NTSB's proposals "-concern the inerting and insulation of fuel tanks and the determination of and controlling of fuel temperature by fuel-load management".

Source: Flight International