Module 3 - Arson and Explosives

In 1988, the Lockerbie air disaster became the deadliest terrorist attack on U.S. civilians until the 9-11 World Trade Center tragedy occurred in 2001.

Pan Am flight 103 was a large Boeing 747 that flew daily between London's Heathrow International Airport and New York's John F. Kennedy International Airport. Just a few days before Christmas 1988, an explosive device was detonated on the airplane, which caused the aircraft to explode in mid-air. The plane’s fuselage and the bodies of the 270 crew and passengers were scattered across an area near Lockerbie, Scotland. Eleven inhabitants of the small town were also killed.

The Explosion: The fuselage of the aircraft was reconstructed by air accident investigators. It revealed a 45 cm hole in the front cargo hold of the airplane. Examination of fragments from front cargo hold showed an area of blackening, pitting, and severe damage. Investigators conducted a series of test explosions to confirm the precise location and quantity of explosive used.

Investigators concluded that the nose separated from the main section of the aircraft within three seconds of the explosion. Because the explosion happened so quickly, the crew were unable to place a distress call. Winds of 190 kilometres per hour scattered victims and plane debris over approximately 2189 square kilometres.

The nose of the airplane, which was found in Lockerbie, contained all the bodies of the flight crew and several first class passengers. Examination of the cockpit showed that no crew member was wearing an oxygen mask. This is further evidence that indicating there was no time to begin any emergency procedures.

As it fell from the sky, the main section of the plane broke into smaller pieces. A large section attached to the wings landed in the middle of a residential area of Lockerbie. Aviation fuel in the tanks in the wings ignited to cause a huge fire destroying several houses. The fire was so intense that nothing remained of the left wing and the only way investigators were able to determine where the plane’s wings had landed was by finding a large number of large screws used only in the wings in the fire debris.

The initial crash site was investigated by local police. However, the military also helped by providing helicopter surveys and satellite imaging. More than 10 000 pieces of evidence was found, tagged, and entered into a computer tracking system.

Cause of the Explosion

Forensic investigators determined that about 450 grams of a plastic explosive called Semtex hidden inside an unaccompanied piece of luggage was responsible for the explosion. Fragments of a Samsonite suitcase believed to have contained the explosive device were recovered, as were pieces of a circuit board from a radio cassette player. The time-delay explosive device was concealed inside the radio cassette player that was hidden in the suitcase along with some baby clothes.

Semtex is a general-purpose plastic explosive developed in the Czech Republic in the 1960s. Semtex was originally designed for commercial blasting and demolition; however, it became popular with terrorists because it cannot be detected by metal detectors and it is easy to obtain. Prior to the 1990s, Semtex could not be detected by X-ray machines. Semtex is considered very effective for attacks on airplanes because only a small amount is needed to destroy a large commercial passenger airplane. Semtex has been used in attacks by Middle Eastern Islamic militant groups, the Irish Republican Army (IRA), and the Irish National Liberation Army. Prior to 2002, Semtex was widely exported. The country receiving the most of this explosive was Libya with over 700 tonnes being imported between 1975 and 1981.

Because Semtex has been associated with terrorist attacks, production and export of Semtex today has been restricted to about 10 tonnes per year only. In addition, the chemical compound, ethylene glycol dinitrate, which is easily identified by explosive detection devices, is now added to Semtex.

In May 1997, a Czech scientist rumoured to have been involved with inventing Semtex, strapped the explosive to his body and committed suicide. Twenty-six people were injured in the explosion.

The Warning: A few weeks prior to the explosion, a man with an Arabic accent phoned the U.S. Embassy in Finland and warned them that a Pan Am flight from Frankfurt to the United States would be blown up within the next two weeks by someone associated with the Abu Nidal Organization, a Palestinian terrorist group. The caller said a woman passenger would unknowingly carry the bomb aboard. The threat was taken seriously, and bulletins were sent to dozens of embassies and American airline companies. Unfortunately, despite the warnings the bomb slipped on board Pan Am flight 103.

A security screener from the Frankfurt airport, whose job it was to spot explosive devices under X-ray, told ABC News after the explosion that she did not know what Semtex was.

The Bombers: After a three-year joint investigation by local police agencies in Scotland and the FBI, indictments for murder were issued for two men from Libya. Both men worked for Libyan Arab Airlines (LAA). One suspect was the head of security while the other was a station manager for LAA. Extradition of the two culprits from Libya to Scotland where they were tried took more than eight years. The extradition involved United Nations sanctions against Libya and direct negotiations with the Libyan leader Colonel Muammar al-Gaddafi.

In 2001, one of the culprits was convicted of murder and sentenced to 27 years in prison by a panel of three Scottish judges. The other suspect was acquitted.

During World War II, allied bombers dropped high explosives to expose the wooden timbers in buildings and to rupture water mains. This was followed immediately by a wave of incendiary cluster bombs to start a large fire. After fifteen minutes, a third wave dropped fragmentation bombs. This time delay between bombings intentionally allowed firefighters and their equipment to be caught in the open and destroyed. The furnace-like conditions created in these fires were often hot enough to cremate the corpses they created.

Why did investigators reconstruct parts of the airplane involved in this explosion?
Ans.  The airplane was reconstructed to determine the site or origin of the bomb.

Where was the site of origin of the explosion? How was this determined?
Ans. Investigators determined this by examining fragments from the front cargo hold, which showed an area of blackening, pitting, and severe damage.

The explosion originated in the front cargo hold.

What type of bomb was used—high or low?
Ans.  A high explosive device was used.