British European Airways flight 284 departed London-Heathrow Airport at 21:45 hours on 11 October 1967, bound for Athens, Greece and Nicosia, Cyprus. The DH-106 Comet arrived at Athens at 01:11 hours on October 12. Six passengers disembarked and 27 passengers joined the flight. It was refuelled and serviced for the flight to Nicosia. The aircraft taxied out at 02:27 hours and was airborne on schedule at 02:31; it was cleared by Athens Control to Nicosia on Upper Airway Red 19 to cruise at FL290. After takeoff it climbed to 4000 ft on the 180 radial of Athens VOR and then turned direct to Sounion, which it reported crossing at 02:36 hours. At 02:46 hours, the aircraft reported that it was crossing R19B at FL290 and was estimating Rhodes at 03:03. At 03:16 hours the crew reported passing R19C at FL290 and estimated passing abeam of Myrtou, Cyprus, at 03:40 hours. This message was not received by Athens direct but was relayed by a westbound Comet aircraft. Flight 284 was then cleared by Athens to change to the Nicosia FIR frequency. Immediately after contacting Nicosia, contact was lost. At that moment a high explosive device detonated within the cabin under seat 4A or 5A. The explosion severely damaged the aircraft causing an out-of-control condition followed by structural break-up at FL150. The wreckage fell into the sea. PROBABLE CAUSE: “The aircraft broke up in the air following detonation of a high explosive device within the cabin.”