1958 Tybee Island mid-air collision

The Tybee Island mid-air collision was an incident on February 5, 1958, in which the United States Air Force lost a 7,600-pound (3,400 kg) Mark 15 nuclear bomb in the waters off Tybee Island near Savannah, Georgia, United States. During a night practice exercise, an F-86 fighter plane collided with the B-47 bomber carrying the large weapon.

1958 Tybee Island mid-air collision
A Mk 15 nuclear bomb of the type lost
when jettisoned after the collision
Midair Collision
DateFebruary 5, 1958
SummaryMidair collision
SiteTybee Island, Georgia, U.S.
32°0′N 80°51′W
First aircraft
TypeBoeing B-47 Stratojet
OperatorUnited States Air Force
(Strategic Air Command)
Registration51-2349
Crew3
Fatalities0
Second aircraft
TypeNorth American F-86 Sabre
OperatorUnited States Air Force
(Tactical Air Command)
Crew1
Fatalities0

To protect the aircrew from a possible detonation in the event of a crash, the bomb was jettisoned. Following several unsuccessful searches, the bomb was presumed lost somewhere in Wassaw Sound off the shores of Tybee Island.

Midair collision
1958 Tybee Island mid-air collision is located in the United States
1958 Tybee Island mid-air collision
Location in the United States
1958 Tybee Island mid-air collision is located in Georgia
Crash site 
Crash site 
Atlanta
Atlanta
Georgia

The B-47 bomber was on a simulated combat mission from Homestead Air Force Base in Florida,[1] carrying a single 7,600-pound (3,400 kg) bomb. At about 2:00 a.m. EST (UTC−5), an F-86 fighter collided with the six-engine B-47. The F-86 pilot, Lt. Clarence Stewart, ejected and parachuted to safety near Estill, South Carolina, ten miles (16 km) north of the fighter's crash site east of Sylvania, Georgia.[2][3] The damaged B-47 remained airborne, plummeting 18,000 feet (5,500 m) from 38,000 feet (12,000 m) when the pilot, Colonel Howard Richardson, regained flight control.[4][5]

The crew requested permission to jettison the bomb, in order to reduce weight and prevent the bomb from exploding during an emergency landing. Permission was granted, and the bomb was jettisoned at 7,200 feet (2,200 m) while the bomber was traveling at about 200 knots (370 km/h). The crew did not see an explosion when the bomb struck the sea. They managed to land the B-47 safely at nearby Hunter Air Force Base, just south of Savannah.[6] Colonel Richardson was awarded the Distinguished Flying Cross after this incident.[5]

The bomb
"Temporary Custodian Receipt" for what would be the nuclear weapon lost in the 1958 Tybee Island mid-air collision. It indicates that the core (part "C") was "simulated," and not an actual fissile core of nuclear material.

Some sources describe the bomb as a functional nuclear weapon, but others describe it as disabled. If it had a plutonium nuclear core installed, it was a fully functional weapon. If it had a dummy core installed, it was incapable of producing a nuclear explosion but could still produce a conventional explosion. Twelve feet (3.7 m) in length, the Mark 15 bomb weighs 7,600 pounds (3,400 kg), bears the serial number 47782, and contains 400 pounds (180 kg) of conventional high explosives and highly enriched uranium.[7]

The Air Force maintains that its "nuclear capsule" (physics package), used to initiate the nuclear reaction, was removed before its flight aboard the B-47.[8] As noted in the Atomic Energy Commission "Form AL-569 Temporary Custodian Receipt (for maneuvers)", signed by the aircraft commander, the bomb contained a simulated 150-pound (68 kg) cap made of lead.[9]

However, according to 1966 Congressional testimony by Assistant Secretary of Defense W.J. Howard, the Tybee Island bomb was a "complete weapon, a bomb with a nuclear capsule" and one of two weapons lost that contained a plutonium trigger.[10] Nevertheless, a study of the Strategic Air Command documents indicates that Alert Force test flights in February 1958 with the older Mark 15 payloads were not authorized to fly with nuclear capsules on board. Such approval was pending deployment of safer "sealed-pit nuclear capsule" weapons, which did not begin deployment until June 1958.[11]

Recovery efforts

Starting on February 6, 1958, the Air Force 2700th Explosive Ordnance Disposal Squadron and 100 Navy personnel equipped with hand-held sonar and galvanic drag and cable sweeps mounted a search. On April 16, the military announced the search had been unsuccessful. Based on a hydrographic survey in 2001, the bomb was thought by the Department of Energy to lie buried under 5 to 15 feet (1.5 to 4.6 m) of silt at the bottom of Wassaw Sound.[8]

In 2004, retired USAF Lt. Colonel Derek Duke claimed to have narrowed the possible resting spot of the bomb down to a small area approximately the size of a football field. He and his partner located the area by trawling in their boat with a Geiger counter in tow. Secondary radioactive particles four times naturally occurring levels were detected and mapped, and the site of radiation origination triangulated. An Air Force nuclear weapons adviser speculated that the source of the radiation was natural, originating from monazite deposits.[12]

Ongoing concerns

As of 2007, no undue levels of unnatural radioactive contamination have been detected in the regional Upper Floridan aquifer by the Georgia Department of Natural Resources (over and above the already high levels thought to be due to monazite, a locally occurring mineral that is naturally radioactive).[13][14]

In February 2015, a fake news web site ran an article stating that the bomb was found by vacationing Canadian divers and that the bomb had since been removed from the bay. The fake story spread widely via social media.[15]

The MonsterVerse graphic novel Godzilla Dominion has the Titan Scylla find the sunken warhead off the coast of Savannah, Georgia, having sensed its radiation as a potential food source, only for Godzilla and the US Coast Guard to drive her into a retreat and safely recover the bomb.

See also

Notes
  1. Mark Natola, ed. (2002). Boeing B-47 Stratojet. Schiffer Publishing Ltd. pp. 77–80. ISBN 0764316702.
  2. "2 planes collide in midair; pilots and crew unhurt". Spokane Daily Chronicle. (Washington). Associated Press. February 5, 1958. p. 1.
  3. "Jet, bomber collide today". Rome News-Tribune. (Georgia). Associated Press. February 5, 1958. p. 1.
  4. Boeing B-47 Stratojet
  5. BBC News, Missing for 50 years – US nuclear bomb (June 22, 2009)
  6. "Damaged bomber makes safe landing". Pittsburgh Post-Gazette. Associated Press. February 6, 1958. p. 2.
  7. "Complete List of All U.S. Nuclear Weapons". Archived from the original on December 16, 2008. Retrieved November 11, 2008.
  8. "Air Force Search & Recovery Assessment of the 1958 Savannah, B-47 Accident" (PDF). Air Force Nuclear Weapons and Counterproliferation Agency (PDF). April 12, 2001. Archived from the original (PDF) on April 8, 2016. Retrieved February 27, 2010.
  9. The Nuclear Information Project Archived November 3, 2005, at the Wayback Machine, Form AL-569, "Temporary Custodian Receipt (for maneuvers)," to U.S. Atomic Energy Commission, Albuquerque Operations, from James W. Twitty, Col., U.S. Air Force, February 4, 1958. Released under FOIA. (PDF)
  10. NPR Media, Letter of W.J. Howard, Assistant to the Secretary of Defense (Atomic Energy), to the Chairman of the Joint Committee on Atomic Energy, Congress of the United States (April 22, 1966). (PDF) Page 1, Page2.
  11. The Nuclear Information Project, History of the Strategic Air Command January 1, 1958 – June 30, 1958. Released under FOIA. (PDF) Archived July 9, 2015, at the Wayback Machine
  12. Lost H-bomb: RIP Archived February 5, 2018, at the Wayback Machine
  13. America's Lost H Bomb Archived October 30, 2010, at the Wayback Machine, Discovery's Science Channel documentary about the Tybee Bomb (2007)
  14. Chatham County Public Works and Park Services, Drinking Water Quality Consumer Confidence Report (2007) Archived August 9, 2009, at the Wayback Machine
  15. "Georgia Warhead". snopes.com. Snopes. February 27, 2015. Retrieved May 6, 2015.

References
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