The Lockheed EC-121H Super Constellation, attached to the 961st Airborne Early Warning and Control Squadron, was assigned to an air defense mission to airborne long-range input (ALRI) station 2. Estimated time en route was 9 hours plus 50 minutes. On 10 November, 1966 at 23:38 local time, the aircraft taxied to the maintenance ramp reporting malfunctions on the no. 1 engine #1 cylinder And no. 2 engine #1 power Recovery Turbine (prt). The spark plugs, coils and leads were changed on #1 cylinder no. 1 engine, and the clamps were tightened on #1 PRT, no. 2 engine. Engines were again started at 00:20, November 11, and the aircraft took off from Otis AFB runway 23 at 00:37. While en route the flight crew radioed: “still have flames coming from PRT #2 engine”. However the aircraft-continued on its mission. At 01:25 all radar contact was lost. A minute later the aircraft was seen to pass over two fishing vessels at low altitude (150-200ft). One or more engines were heard to be backfiring. The aircraft later hit the water and burst into flames. Only a widening oil slick and a few bits of floating debris marked the spot of the crash. Recovered were pieces of aircraft skin and insulation, a seat with a cushion, and three empty life preservers. Air Force officials identified them as from the missing plane.