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Mk 4 atomic bomb like that lost in 1950
CONTRIBUTION · 12th February 2010
Helene McRae & Merv Ritchie
On Sat. Feb. 13th from 1 to 3 p.m. at Heritage Park Museum, Norman Leach, author of "Broken Arrow - America's First Lost Nuclear Weapon", will give a talk. This is the 60 year anniversity of the crash of the US B36 Bomber in the Kispiox, north of the Hazelton mountains. Bulkley Valley Museum is the co-host of Leach. Books will be available.

A breif summary of the incident is;

13 February 1950: While flying a simulated combat mission from Eielson Air Force Base in Alaska to Carswell AFB in Texas, a B-36 Peacemaker bomber experienced engine problems. The aircraft was carrying a single Mk 4 atomic bomb containing depleted uranium but the plutonium core required for a fission reaction had been removed. Ice buildup on the carburetors forced the pilot to shut down three engines and reduced the power output of the remaining three. As weather conditions continued to worsen, the crew decided to abandon the aircraft. The unarmed bomb was jettisoned over the Pacific Ocean and its conventional explosives either detonated in mid-air or upon impact with the water. The plane then turned over a nearby island where the crew bailed out. Twelve were rescued from the frigid conditions but five were never found. The B-36 apparently continued on autopilot for a considerable distance before crashing in northern British Columbia. The wreck was later located and studied to confirm that no nuclear material remained aboard.

More details

Direct from Wikipedia

On February 13, 1950, a Convair B-36B, serial number 44-92075, assigned to the 7th Bomb Wing at Carswell Air Force Base, crashed in northern British Columbia, after jettisoning a Mark IV atomic bomb. This was the first time in history that a nuclear weapon was lost. 44-92075 was flying from Eielson Air Force Base near Fairbanks, Alaska, to Carswell AFB in Fort Worth, Texas, on a mission that included a simulated nuclear attack on San Francisco, California.

Incident

Airplane 44-92075 was on a mission that was part of the first full-scale practice nuclear strike against the Soviet Union. Each B-36 involved in this exercise was to conduct a simulated nuclear attack on an American city. The exercise was also intended to test whether the B-36 could attack the Soviet Union during the Arctic winter, when temperatures were so low that the engines could not be shut down while a plane was being serviced on the ground.

Plane 44-92075 took off from Eielson AFB with a crew of 16 plus one observer. 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. The flight plan did not include any penetration of Canadian airspace. The plane carried a Mark IV atomic bomb, containing a substantial quantity of natural uranium and 5000 pounds of conventional explosives. According to the USAF, the bomb did not contain the plutonium core necessary for a nuclear detonation.

Cold weather (-40F on the ground at Eielson AFB) adversely affected the planes involved in this exercise, and some minor difficulties with 44-92075 were noted before takeoff. Seven hours into the flight, three of the six engines began shooting flames and were shut down, and the other three engines proved incapable of delivering full power. The subsequent investigation blamed ice buildup in the mixture control 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 Pacific. The USAF later stated that the fake practice core on board the aircraft was inserted into the weapon before it was dropped.

The captain steered the plane over Princess Royal Island to spare his crew having to parachute into the cold North Pacific, whereupon the crew bailed out. Before bailing out last, the captain set a turning course over to the open ocean using the autopilot.

The plane had always been in radio contact with the Strategic Air Command and within minutes of the bailout the Canadian military launched Operation Brix to find the missing men. Poor weather hampered the search efforts; nevertheless 12 of the 17 men were eventually found alive. The five deceased airmen were believed to have bailed out of the aircraft earlier than the surviving crewmembers, and it was assumed that they landed in the ocean and drowned. The Canadian authorities were never told that the aircraft was carrying a nuclear weapon.

Subsequent events

An exhaustive search was not launched for the plane as it was believed to be at the bottom of the Pacific. Three years later, however, a USAF flight searching for missing millionaire Ellis Hall spotted the plane's wreckage, nearly completely intact, on the side of Mount Kologet, about 50 miles from the Alaskan border, roughly due east from the towns of Stewart, BC and Hyder, AK, on the east side of the isolated Nass Basin northwest of Hazelton, British Columbia.

The USAF immediately began an investigation. A team was sent in September 1953 but was not given a high priority. After 19 days of trudging through the wilderness, they failed to reach the site. The effort was resumed the following year with better equipment, and in August 1954 a new team of USAF personnel with a local guide reached the wreckage. They recovered important components and then used explosives to destroy what was visible above the snow. The American and Canadian military kept the location of the wreck secret, though the operation had been run openly and the general details were known to the public. Curiously, when the American military first released information about the crash decades later, the documents falsely stated that the wreck had been found on distant Vancouver Island.

In 1956, two civilian surveyors chanced on the wreck and noted its exact location, which otherwise remained unknown for the next 40 years. In 1997 one of the surveyors provided the coordinates to two distinct expeditions, one American and one led by the Canadian Department of National Defence, seeking to conduct an environmental analysis of the site. Both expeditions reached the wreck around the same time, and were apparently the first humans to set foot in the area since 1956. These environmental missions found no unusual radiation levels, and led to the crash location becoming public knowledge. Local salvage efforts began, with many items going to local museums. In late 1998, the Canadian government declared the site protected.

Discussion

It is not known just how 44-92075 crashed into Mount Kologet in the mountains of northern British Columbia rather than into the Pacific. To reach the crash point, the plane had to have flown north for some hours after the crew had bailed out, and to have cleared terrain whose altitude exceeded the altitude at which the crew bailed out. It can be surmised that the three engines that were not shut down must have recovered from icing, resulting in enough increased power to enable the aircraft to remain airborne and even climb. It is possible that the autopilot turn setting caused the abandoned plane to fly in circles, after which the prevailing winds carried it to the crash site. Rescue and weather records show that the strength and direction of the prevailing winds were consistent with this scenario. Another theory is that the plane entered a hot air stream and the ice on one wing melted. The weight change caused the plane to bank and fly in circles. Then the ice on the other wing fell off. The plane continued over the mountains and into the Interior where it crashed.

It has been speculated that Captain Ted Schreier, one of the five whose body was never found, did not bail out with the others, but instead tried to fly the plane back to Alaska.[1] A local legend in Smithers, BC, has it that the USAF recovered a body from the wreckage in 1954.