Exploding 747 makes life safer for passengers

Ever since the PAN-AM 103 disaster at Lockerbie, work has been carried out into methods of protecting aircraft from explosive devices. Bomb incidents against civil aircraft have already involved 33 countries and 40 airlines, and of these instances, 55% of the aircraft have successfully accomplished a controlled landing.

When investigating the effects of an explosion on aircraft structures and systems when devices are hidden in luggage in the aircraft hold, it is important to simulate the density of baggage packing and its effect on the explosion. Recent trials on a pressurised aircraft hull have validated earlier predictions and given additional useful information.

To test a number of structural hardening concepts, a trial for three of them was recently conducted at Bruntingthorpe, Leicestershire. Two different types of hardened baggage container were tested as well as a cargo hold liner that used a synthetic material similar to body armour. The bombs were positioned at various locations in the cargo holds.

The trial, conducted by the DERA for the Civil Aviation Authority (CAA) and the US Federal Aviation Administration (FAA), forms part of the Civil Aircraft Explosion Hardening Project.The aircraft used was a wide-bodied Boeing 747, pressurised to the equivalent of 35,000ft altitude.

One of the four charges was set in the baggage hold against a protective lining developed by the DERA to protect the skin of the aircraft. Another charge was detonated inside a specially designed luggage container provided by the FAA. A third charge tested another concept in liner design. The final charge, at the rear of the fuselage, was a controlled explosion to demonstrate the effects of blast on an unprotected aircraft, which was expected to fail. The explosions took place simultaneously.

As anticipated by the testers, the control explosion wrecked the rear of the aircraft, and blew out nine windows. Externally, the three protective concepts appeared to provide protection, any visible damage sustained was, in the opinion of the DERA experts, such that the aircraft would have been able to continue to a safe landing.

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