Airlines

By Darren Shannon in Washington DC

An investigation of the 4 May explosion of a Transmile Airlines Boeing 727-200 freighter’s left wing during towing at Bangalore airport has found evidence of damaged wiring and electrical arcing within the wing’s fuel tank.

In an update issued today by the US National Transportation Safety Board (NTSB), the investigators also note that the aircraft was compliant with a FAA airworthiness directive requiring plastic sleeving for all wires, but that this “however, did not prove to be sufficient to prevent the Bangalore accident”.

“The evidence indicates that an explosion in the left wing fuel tank destroyed the structural integrity of the wing,” says the NTSB in its update.

“Had this explosion occurred in flight, it would have resulted in the catastrophic failure of the wing and the airplane would have crashed,” it adds.

An on-scene NTSB-led team, which also travelled to the Malaysian carrier’s home country, found evidence of damaged wiring, as well as electrical arcing within the left wing the fuel tank in an aluminum conduit tube that carries 115V AC power to the fuel pumps, notes the safety board.

“This accident illustrates that ignition sources continue to exist and fuel tank explosions continue to occur in both wing and center wing fuel tanks despite the corrective efforts of government regulators and industry,” says the NTSB.

It adds: “The safety board continues to believe the best protection against fuel tank explosions is to eliminate the flammable conditions inside the fuel tanks through design changes such as nitrogen-inerting systems.”

The investigation was conducted between May 24 and June 2.