New Container Offers Protection Against Terrorist Bombs

An aircraft baggage container capable of absorbing shock waves from bombs such as the one which destroyed the PanAm 747 over Lockerbie, Scotland, has been developed by Royal Ordnance (RO), a subsidiary of British Aerospace (BAe).

The new Protective Cargo Container (PCC) has undergone extensive trials at RO’s unique Fast Event Facility at Chorley in Lancashire, northern England. The PCC has already aroused interest among both airlines and air freight carriers. The former have the backing of the British Government in combating terrorist activities; the latter will shortly be subject to new stringent regulations which make them responsible for making all cargo safe for transit. Made of secret materials which absorb and minimise the impact of an explosion occurring in the baggage hold, the PCC has the same dimensions as the conventional LD3 aircraft baggage containers flown on all international airlines and fits the same envelope. The container design takes full advantage of the lessons learned from conventional containers, providing practical doors and durable bases. Capable of being loaded by forklift truck and within the current weight limits laid down by the US FAA, PCC can be flat packed and is expected to be manufactured under licence. Only slightly higher in cost than the baggage container it is likely to replace, the new unit was expected to become available in the first half of 1995. The potential market for PCC is anticipated to be 300,000 units worldwide. Andrew Jeacock, public relations manager of BAe, said however that the new design would not protect an aircraft against very large bombs. “You cannot guarantee protecting anything against a really determined terrorist, nor could this container stop a much larger device from destroying an aircraft. But airport security authorities should now be able to detect bigger bombs than that used over the Scottish town of Lockerbie”. Mr Jeacock said that RO engineers had been closely involved with the authorities in analysing the size and type of bomb placed in the baggage hold of PanAm flight 103 which exploded over Lockerbie in 1988 killing 270 people. “What happens when there is an explosion is that there is a tremendous spike of pressure energy which is what punched its way through the side of the Lockerbie plane. The aircraft skin was then literally peeled back in the 400 knot (740km/h) winds.” At our site in Chorley, our scientists reproduced exactly what happened at Lockerbie and in our Fast Event Facility we were able to take pictures of this at up to 20 million frames a second, so we know exactly not just what happened but also why our baggage container works. “All of our trials have shown that, unlike conventional baggage containers, ours retains its integrity during and after the blast. It basically offers a three stage defence. The material soaks up some of the blast while more is directed safely downwards into the robust forklift base and into the bilges of the aircraft. “Finally, the external straps retain the container’s eight panels or they are distended by the force of the explosion. The baggage container itself tries to become spherical, which is the most efficient way it can deal with the blast. We have done more than 30 firings and are confident that the PCC can protect an aircraft and its passengers from a Lockerbie size bomb.” The RO film, which graphically demonstrates how the PanAm aircraft was virtually destroyed by the bomb, inspired scientists to reconsider a technology known as blast management. It relies on attenuating the blast wave of any explosion, absorbing energy through deformation of materials and controlling the release of the blast. The secret of the container lies in the careful choice and combination of materials which can survive in the harsh working loading and unloading environment of baggage handling and yet provide attenuation and energy absorption from any blast it might be subjected to. The container reduces dramatically the blast overpressure that occurred in the PanAm aircraft, removing the highly damaging spike from the detonation and, by doing so, allowing the blast to be emitted at a much lower level. The PCC has a false bottom and vents at the top of the container. If an explosion occurs in the baggage hold, materials inside the panels absorb some of the explosive force. As the blast takes on its spherical shape and the container’s panels begin to move, restraining struts take up some of the impact, and the false floor and air vents allow the explosive pressure to be released by taking about four times longer than the customary blast. The aircraft industry is already showing great interest in the PCC, so perhaps after half a decade the tragic loss of PanAm 103 will not entirely have been in vain.