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 southeast, on a mission that included a simulated nuclear attack on San Francisco. 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 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 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. In 1997 one of the surveyors provided the coordinates In late 1998, the Canadian government declared the site protected. A portion of one of the gun turrets is on display at The Bulkley Valley Museum in Smithers, British Columbia.

In late October 2016 a diver reported he had discovered something looking like a segment of the partially disarmed Mark IV nuclear bomb which the co-pilot said had been dumped before the crash. The location near Pitt Island in the Inside Passage was mistakenly reported as off Haida Gwaii. The Royal Canadian Navy later confirmed that the item was not the Mark IV bomb.

See also

  • List of military nuclear accidents
  • Nuclear weapons of the United States

References

Sources

  • "Broken Arrow ," Dirk Septer. BC Aviator 3, no. 2 (October–November 1993): 23–27 .
  • Site with links to Canadian Dept. of National Defence report and to news stories.
  • Convair B-36 Crash Reports and Wreck Sites with pictures of the crash site.
  • Transcript of an interview with a crew survivor.
  • 2004 Canadian documentary film about the incident.
  • "Broken Arrow – The Declassified History of U.S. Nuclear Weapons Accidents" by Michael H. Maggelet and James C. Oskins .