

On 13 February 1950, a USAF B-36B – carrying a Mark IV nuclear bomb with what was reportedly a “dummy” (lead) nuclear capsule – took off from Eielson AFB, Alaska. It was headed to Carswell AFB, TX (now NAS Fort Worth JRB). Its mission included a simulated nuclear attack on San Francisco en route.
Shortly before midnight, while over the Pacific, the plane experienced major engine problems – as in “three of the plane’s 6 engines caught fire and were shut down.” Because of what was later determined likely to have been mixture control icing, the three functional engines did not appear capable of producing enough power to maintain flight.
The pilot flew over Princess Royal Island, Canada – 300+ miles north of Vancouver – and the crew abandoned the aircraft. Twelve of the 17 crew were rescued alive. Four of those lost were believed to have abandoned the aircraft before it arrived over land; the remains of the fifth were reportedly found at the aircraft’s crash site.
The aircraft reportedly dropped its weapon prior to reaching the coast, and it was reported to have exploded in midair. Since it had an inert (lead) capsule vice the active nuclear capsule that would have been present in a fully-armed weapon, the resulting explosion wasn’t nuclear. However, it was nonetheless sizeable; the weapon’s design contained a relatively large amount of high explosive, which was required to implode the weapon’s core.
The aircraft’s pilot reported having set the autopilot to take the aircraft west, out to sea, before he jumped. However, the autopilot apparently malfunctioned – or perhaps was set improperly due to stress or haste (quite understandable under the circumstances).
Rather than flying out to sea, the aircraft eventually ended up heading generally NNE. The aircraft ultimately crashed about 50 miles east of the border towns of Hyder, Alaska, and Stewart, British Columbia; the crash site wasn’t located until over 3 1/2 years later. The crash site is roughly 150 miles from Princess Royal Island.
Yeah, that’s an interesting piece of history. But I know many of you are likely thinking, “Why mention this now?”
Well, it appears that a Canadian diver may have found the remains of the jettisoned bomb – or at least some parts of it that survived the explosion.
The diver, Sean Smyrichinsky, was diving near Banks Island, Canada, earlier this year. He noticed something odd – something he’d never seen before. On returning to his boat he described it to the crew as resembling “a bagel cut in half, and then around the bagel these bowls molded into it.”
Afterwards, Smyrichinsky asked around. He learned of the 1950 incident. On seeing photos of a Mark IV nuclear bomb, he indicated that looked like what he’d seen.
The Canadian Navy is preparing to investigate Smyrichinsky’s find.