The aircraft was conducting a special flight from Westover AFB to RAF Brize Norton, near London, carrying a crew of seven and eight american journalists who covered the first transatlantic flight on a KC-135 airplane. Two other similar aircraft left the airbase earlier and 56-3599 was the third of a series of four. At liftoff from runway 23, the airplane encountered serious difficulties to gain height and struck trees with its right wing. It then struck power cables and crashed in a huge explosion on the Massachusetts highway about 1,000 yards past the runway end. The aircraft disintegrated on impact and all 15 occupants have been killed.
Probable cause (official findings): It was determined that the flaps were deployed at a wrong angle of 40° at takeoff. The combination of a wrong flaps setting with an heavily loaded aircraft and relative high temperature reduced the aircraft performances. At the time of the accident, the visibility was estimated to 2,5 km due to the night and low ceiling. No mechanical failure of any means and no in-flight fire occurred prior to final impact.