Pan Am Flight 103 Bombing Investigation - Reconstruction of The Aircraft and Luggage Containers

Reconstruction of The Aircraft and Luggage Containers

All parts of the recovered aircraft were taken initially to a hangar at Longtown, Cumbria, where they were examined by investigators from Britain's AAIB; they were then moved to the AAIB's headquarters at Farnborough Airfield in Hampshire for the fuselage of the Boeing 747 to be partially reconstructed. Investigators found an area on the left side of the lower fuselage in the forward cargo hold, directly under the aircraft's navigation and communications systems, where a small section of about 20-inch (0.51 m) square had been completely shattered, with signs of pitting and sooting. The fuselage skin had been bent and torn back in a so-called starburst pattern—petalled outwards—a pattern that was evidence of an explosion.

The forward cargo hold had been loaded with 148-cubic-foot (4.2 m3) capacity baggage containers, made either of fibre or aluminium, and filled with suitcases. After the explosion, most of these containers showed damage consistent with a fall from 31,000-foot (9,400 m), but two of them—metal container AVE4041 and fibre container AVN7511—showed unusual damage. From the loading plan, investigators saw that AVE4041 had been situated inboard of, and slightly above, the starburst-patterned hole in the fuselage, with AVN7511 right next to it. The reconstruction of container AVE4041 showed blackening, pitting, and severe damage to the floor panel and other areas, indicating that what the investigators called a "high-energy event" had taken place inside it. Though the floor of the container was damaged, there was no blackening or pitting of it. From this, and the distribution of sooting and pitting elsewhere, investigators calculated that the suitcase containing the bomb had not rested on the floor, but had probably been on top of another case, though there was no proof that the explosion had occurred in a suitcase.

Using the damage to adjacent container AVN7511 to guide them, the investigators concluded that the explosion had occurred about 13 inches (330mm) from the floor of AVE4041 and about 25 inches (640mm) from the skin of the fuselage. Federal Aviation Administration (FAA) investigators then conducted a series of tests in the United States, at which Alan Feraday of Britain's Defence Evaluation and Research Agency (DERA) is understood to have been present. The tests involved using metal containers loaded with luggage, and detonating plastic explosive within Toshiba radio cassette players in garment-filled suitcases, so as to replicate the sooting and pitting pattern of AVE4041. The tests were said to have proved AAIB investigators' theory concerning both the position of the bomb and the quantity of explosive involved. The results of these tests were used as evidence at the eventual trial to determine the origin of the bomb suitcase. John Bedford, one of Pan Am's loader-drivers at Heathrow, was able to give evidence about the precise location within PA 103 of the baggage container, as well as the location of suitcases inside it, all of which helped investigators piece together how the bomb suitcase came to be there. Bedford particularly remembered handling container AVE4041, he told investigators, because he was born in 1940, and his wife in 1941.