1950 British Columbia B-36 crash

Sometime after midnight on 14 February 1950, a Convair B-36B, United States Air Force Serial Number 44-92075 assigned to the US 7th Bombardment Wing, Heavy at Carswell Air Force Base in Texas, crashed in northwestern British Columbia on Mount Kologet after jettisoning a Mark 4 nuclear bomb. This was the first such nuclear weapon loss in history. The B-36B had been en route from Eielson Air Force Base near Fairbanks, Alaska, to Carswell AFB, more than 3000 mi southeast, on a mission that included a simulated nuclear attack on San Francisco.

Incident

Convair B-36B 44-92075 was flying on a simulated nuclear strike combat mission by the Soviet Union. The B-36 took off on 13 February 1950 from Eielson AFB with a regular crew of 15 plus a Weaponeer and a Bomb Commander. The plan for the 24-hour flight was to fly over the North Pacific, due west of the Alaska panhandle and British Columbia, then head inland over Washington state and Montana. Here the B-36 would climb to 40000 ft for a simulated bomb run to southern California and then San Francisco, and it would continue its non-stop flight to Fort Worth, Texas. The flight plan did not include any penetration of Canadian airspace. The aircraft carried a Mark 4 atomic bomb, containing a substantial quantity of natural uranium and 5000 lb of conventional explosives. The bomb did not contain the plutonium core necessary for a nuclear detonation. Until 1951, the US military had no nuclear cores in its possession, as they were still entirely in the custody of the U.S. Atomic Energy Commission. The flight did contain a "dummy capsule," a simulated container for a nuclear core (filled with lead), which was recovered much later.

Cold weather (-40 F on the ground at Eielson AFB) adversely affected the aircraft involved in this exercise, and some minor difficulties with 44-92075 were noted before takeoff. Seven hours into the flight, three of the six piston engines began shooting flames and were shut down, and the other three piston engines proved incapable of delivering full power. The subsequent investigation blamed ice buildup in the carburetor air intakes.

The crew decided to abandon the aircraft because it could not stay aloft with three engines out of commission while carrying a heavy payload. The atomic bomb was jettisoned and detonated in mid-air, resulting in a large conventional explosion over the Inside Passage. The USAF later stated that the fake practice core on board the aircraft was inserted into the weapon before it was dropped.

The aircraft was in regular radio contact with Strategic Air Command headquarters at Offutt AFB, Nebraska. The crew bailed out, using parachutes.

Within minutes of the bailout the Royal Canadian Air Force launched Operation Brix to find the missing men. Poor weather hampered search efforts; nevertheless 12 of the 17 men were eventually found alive. One of the five deceased, the weaponeer, was rumored to have been recovered four years later (1954) at the crash site. The remaining four airmen were believed to have bailed out of the aircraft earlier than the surviving crew members, and it was assumed that they landed in the ocean and died of hypothermia. Canadian authorities were never told that the aircraft was carrying a nuclear weapon.