A Douglas DC-4 operated by Maritime Central Airways crashed after the flight crew lost of control of the aircraft in turbulence. The aircraft was destroyed and all 79 on board were killed. The flight departed London, U.K. at 21:48 hours GMT (August 10) for a flight to Toronto, Canada with refueling stops at Keflavik, Iceland and Goose Bay, Canada. The aircraft departed Keflavik at 05:12 GMT (August 11) following a 66-minute stop. At 13:20 GMT the aircraft, following receipt of the Montreal weather forecast, advised Goose Bay that it would overfly Goose Bay and proceed to Montreal. Approaching Goose Bay a request for a clearance to cruise at 4000 ft to Lake Eon and at 6000 ft to Montreal was denied, following which the pilot chose to proceed VFR on Airway Red 1 until a clearance was issued at 16:07 GMT for an IFR flight at 6000 ft. The aircraft reached Quebec at 18:07 and then estimated arrival at Montreal at 19:02 GMT. Last radio contact was at 18:10 when Quebec Radio Range Station relayed a message to the aircraft requesting it to contact Montreal Range approaching Rougemont for clearance. The aircraft was flying at about 6000 feet when it entered an active cumulonimbus cloud, including heavy rain and strong gusty winds. In these conditions the aircraft entered an uncontrolled descent until it struck the ground in an almost vertical (70 degrees nose down, slightly left wing down) attitude at a speed over 200 kts. PROBABLE CAUSE: “Severe turbulence encountered whilst flying in a cumulonimbus cloud, resulting in a chain of events quickly leading up to a complete loss of control and causing the aircraft to dive to the ground in a near vertical nose-down attitude.”