|You are in: Special Report: 1998: 12/98: Lockerbie|
Monday, 21 December, 1998, 09:43 GMT
Lessons from Lockerbie
By Aviation & Transport Correspondent Christopher Wain
It was an ordinary suitcase, but there was nothing ordinary about its contents. Inside the suitcase was a Toshiba portable radio/cassette player. Like most of its counterparts, the imposing case had quite a lot of empty space.
Inside the case a larger-than-normal battery was wired to a barometric sensor (the bellows unit from an aneroid barometer), a small device concealed under the cassette-play motor. This in turn was set to start a timer, which in turn was wired to a detonator.
In the space where there should have been a loudspeaker, there was shallow cone of silver foil, filled with about 350 grammes of Semtex plastic explosive.
It was a crude but brilliant device, designed for mass murder.
How it worked
Or the carrier may have been an innocent - carrying a present. (It's an old dodge: In 1986 a pregnant woman flying out from Heathrow to Tel-Aviv was found carrying a gift-wrapped bomb. It had been given to her by her Palestinian "boyfriend" who told her it was a Christmas present. It was found by El-Al security staff during a routine baggage-search.)
Alternatively, it may have been an unaccompanied device. It may somehow have been smuggled airside and slipped into the container of New York luggage. (This would have needed someone with an airside security pass and access either to the luggage container or to the baggage train. The suitcase would also have needed the correct destination baggage-tag.)
Either way, once the plane took off for London, things started to happen.
Technology makes tragedy
But it isn't sea-level pressure. To reduce wear-and-tear on the fuselage, the pressure is normally equivalent to an altitude of about eight thousand feet. The pressure is less than it would be at sea-level, but more than it would be outside. (On the journey to London most planes cruise at 20,000 to 25,000 feet.)
The moment the pressure dropped to 8,000 feet, the barometric sensor completed a circuit which started the timer. We don't know for sure how long a delay had been set, but it was probably about 4 hours.
From Frankfurt, this would allow an hour for arrival in London including 10 minutes' holding in the stack; 45 minutes for being taken off the feeder-liner and re-loaded on to the Boeing 747; 15 minutes' start-up, push-back and taxiing before takeoff; and 2 hours flying time - long enough to get the plane far out over the icy waters of the North Atlantic.
If the plan had worked, Pan Am 103 would simply have vanished into the ocean, and probably we would never have known for sure what had happened. But in the event, flight 103 took off over an hour behind schedule. It had been airborne less than an hour when it blew up over Lockerbie.
As the plane cruised at about 30,000 feet, the few ounces of Semtex (the equivalent of about half a dozen hand-grenades) was enough to create unbearable over-pressure. The aircraft blew apart like a balloon, in a fraction of a second.
It was because the wreckage landed on the ground that air accident investigators were able to piece together what happened. Within days they knew it was a bomb; within weeks where it had been placed (it was in the forward cargo-hold, just behind the cockpit); and within months who allegedly had planted, and why.
Could we have stopped it?
Regardless of whether or not the two named suspects are ever brought to trial, three key questions remain: Could the Lockerbie disaster have been prevented; Could it happen again; and can airliners be "hardened" sufficiently to make them bomb-proof?
So too are the checks on passengers, which is why it would be harder to repeat such an attack. Everyone boarding every flight is asked at the check-in: is this your bag? Did you pack it yourself? Has it been out of your sight since it was packed? Does it contain any electrical goods? Are you carrying any presents for anyone?
Once the bags go down to the loading bay, a certain number go through additional checks. No airport likes to discuss these, but they are fairly obvious.
There are highly sophisticated devices which can see or even smell plastic explosives. Virtually every radio, laptop and video can be checked against the maker's diagram to see if (as was the case in the Lockerbie bomb) there are unexplained internal wires or switches.
There are strict checks on unaccompanied luggage - if the bar-code tags can't be matched to a passenger on the computer, the bag doesn't fly (that at least is the theory). And passengers themselves are unobtrusively checked by CCTV for names which are known to each country's immigration service.
There is also a great deal of urgent research going into "hardening" aircraft. Those who remember an old Boeing 747 being blown apart at Bruntingthorpe last year will be surprised to learn the experiment was regarded as an outstanding success.
Two alternative methods of suppressing the blast (armoured luggage containers, and padded walls to channel the blast) both worked. Future generations of aircraft will have terrorist survivability devices built-in, just as military aircraft are able to withstand a certain amount of battle damage.
But there are no grounds for complacency. Toshiba no longer makes radio/cassette-players, and modern terrorists would doubtless regard the Lockerbie bomb design as equally obsolete. Technology has moved a long way since December 1988, on both sides of the terrorist war.
The main defence is still to put in good security measures to prevent unauthorised access to aircraft on the apron, and rigorous passenger-checks to stop the "mules" slipping something aboard through the check-in system. In other words, stop the bombers before they get to the plane.
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