1950 “Broken Arrow” Found?
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.
Category: Air Force, Historical
Watched a good video on YouTube about it. The u.s hade spec ops guys parachute in and blow up the aircraft wreck/move the mess around. One explorer found “the birdcage” used to transport the core separate from the bomb. It was empty.
If the story is correct there was no core onboard as it was a training mission. 1950 would have been before the time we started the airborne alert system that had fully armed bombers flying “racetracks” over North America.
I believe that in this particular type of bomb the only radioactive materials other than the core would have been a natural uranium (i.e. non-enriched) tamper or casing.
Do you think their is a hand receipt holder out their that is signed for a bomb and all they have is a core? This might be a chance to clear the hand receipts without a field loss.
Considering how few of those we had in 1950, no. See below.
That stands to reason, and doesn’t imply that an actual nuclear core was lost.
During the early Cold War, nuclear cores were precious items – and in fairly short supply. We had less than 300 at the end of 1950. They’d likely not have been flown on a training mission of this sort; they didn’t later that year during the crash that killed BGen Travis (that weapon’s nuclear core was on another aircraft).
Published accounts of the incident say that the mission was flown with an inert core. The design of the Mark IV bomb required in-flight arming – e.g., the insertion of the nuclear capsule into the weapon in flight through a port allowing for this task. Those same accounts also say the inert core was inserted into the weapon prior to it being jettisoned during the incident. An inert core would have allowed the crews to practice this without risking a live core on a training mission.
The inert core would have been stored somewhere on-board prior to insertion in the weapon lost. The most likely location for that storage, for both training and practical reasons, would have been the location used to store a real core if present. If so – and if the inert core was inserted prior to jettisoning the weapon during the incident – it thus stands to reason that the “cage” would have been empty at the crash site.
Believe you are correct. In 1959, we had “fat boys” for the B-66’s at RAF Schulthorpe and the accompanying bird cage with the core. They were transitioned to the smaller H bombs. What I am having trouble understanding is why any inert training bomb would contain HE.
The design of the Mark IV was essentially that of the Nagasaki “Fat Man” bomb with minor changes. That design surrounded the nuclear “pit” with a sphere of HE – one account says around 5,000 lbs worth – designed to produce a spherical converging shock wave to implode the core.
One of the mods for the Mark IV allowed the nuclear “pit” to be inserted in flight as a safety measure; the original “Fat Man” design didn’t. In both cases, removing the HE would require disassembling the weapon.
The bomb lost was apparently a stockpile Mark IV – less the nuclear pit. Couldn’t say why they were flying with it, other than to guess for training purposes in in-flight arming of a weapon. That could be practiced with an inert (lead) core, but needed either a real bomb or a faithful mock-up. I’d guess the latter wasn’t readily available.
Alternatively, maybe there was a need to transfer the bomb from Eielson to Carswell. Not a helluva lot of good ways to do that with an early nuke other than by flying it in a bomber – they were huge, and required massive security precautions.
Well, if it’s an old bomb and we built more advanced models, is it really important or is it just a piece of history?
It would be a useful template for
How to build a reliable, portable, multi megaton city-killer, using very simple technology.
There is a staggering amount of engineering that goes into “reliable”, as well as “portable”.
Imagine having only technology for a wet-plate camera, and then finding a 1950s Nikon.
(Revealing how little I know of photography or camera history, pick the top of the line 50s item)
That’s a good point, but Eastman (guy, not company) developed the first film emulsion on a flexible backing, paper, in 1885. That was followed by a transparent nitrocellulose backing in 1896. Eastman was looking for a more portable medium than wet plates and glass. I have a few negatives from my grandfather’s trip to the Klondike gold rush in 1898. Fascinating stuff.
If the crew reports are correct and the bomb indeed exploded after being jettisoned, the parts that would be useful as crude examples (exploding wire detonators, HE lenses, timing mechanism to ensure simultaneous detonation) would have virtually certainly been destroyed in the explosion.
Bluntly, the Mark IV was a pretty crappy bomb. It was more reliable than the Mark III used on Nagasaki, but that’s not saying much. The Mark III was essentially a full-scale lab experiment mounted in a bomb case. The Mark IV’s major improvements were being easier to manufacture and allowing for in-flight insertion of the nuclear core as a safety measure. It was otherwise effectively the same as the “Fat Man” bomb.
The Mark IV was only in service for about 4 years before it was replaced with a better design.
In the interest of keeping an open mind about this, pending the results of the on-site investigation, maybe it is a giant half bagel, with a large dollop of cream cheese sitting on it.
Cheese!!!
Denny?
You just had to say ‘bagel’, dintcha? Now I’m hungry.
That had better be cream cheese with chives.
The B-36B has quite a colorful history surrounding the six engines and their failures.
Scary aircraft to fly from what I’ve read.
No body told Canada about this for a long time. Then there was the time a Soviet spy satellite crashed into them and spilled its weapons grade battery all over the place.
I missed hearing about that one.
Kosmos 954 in 1978.
That explains it. I was in college with a new son – work and study consumed my attention.
I like the part about simulating an attack on San Francisco.?
Yeah, but this was 1950, not 1968. From what I understand it was an ok burg in ’50.
Point of error: A ‘Broken Arrow’ is the detonation of nuclear weapon that can not cause the risk of war. Losing a nuclear weapon through negligence, theft etc. is an ‘Empty Quiver’.