governments. A sleeper cell belonging to the Popular Front for the Liberation of Palestine (General Command) had been operating in West Germany in the months before the Pan Am bombing. In 2020, US authorities indicted the Tunisia resident and Libyan national Abu Agila Mohammad Mas'ud Kheir Al-Marimi, who was 37 years old at the time of the incident for participating in the bombing, and in December 2022, they obtained custody of him. Aircraft The aircraft operating Pan Am Flight 103 was a Boeing 747-121, registered and named Clipper Maid of the Seas; prior to 1979, it had been named Clipper Morning Light. It was the 15th 747 built, and was delivered in February 1970, one month after the first 747 entered service with Pan Am. In 1978, as Clipper Morning Light, it had appeared in "Conquering the Atlantic", the fourth episode of the BBC Television documentary series Diamonds in the Sky, presented by Julian Pettifer. Flight Pan Am 103 originated as a feeder flight at Frankfurt Airport, West Germany, using a Boeing 727 and the flight number PA103-A. Both Pan Am and TWA routinely changed the type of aircraft operating different legs of a flight. PA103 was bookable as either a single Frankfurt–New York or a Frankfurt–Detroit itinerary, though a scheduled change of aircraft took place in London's Heathrow Airport. After the bombing, the flight number was changed, in accordance with standard practice among airlines after disasters. Within days, the Frankfurt–London–New York–Detroit route was being served by Pan Am Flight 3 until the company's demise in 1991. Explosion and collision timeline Departure On its arrival at Heathrow Terminal 3 on the day of the disaster, the passengers and their luggage (as well as an unaccompanied suitcase which was part of the interline luggage on the feeder flight) were transferred directly to Clipper Maid of the Seas, whose previous flight had originated in Los Angeles and arrived via San Francisco. The plane, which operated the flight's transatlantic leg, pushed back from the terminal at 18:04 and took off from runway 27R at 18:25, bound for New York JFK Airport and then Detroit Metropolitan Wayne County Airport. Contrary to many popular accounts of the disaster (though repeated, with reference, below), the flight, which had a scheduled gate departure time of 18:00, left Heathrow airport on time. Loss of contact At 18:58, the aircraft established two-way radio contact with Shanwick Oceanic Area Control