Investigation Summary
The B-47, commanded by Col. Howard Richardson, was participating in a simulated combat exercise when it was struck by an F-86 Sabre piloted by Lt. Clarence Stewart. The F-86 was not part of the B-47's specific mission and failed to detect the bomber in the dark until the collision was unavoidable. The impact severely damaged the B-47's wing and one of its engines. Reports on the initial collision altitude vary between 36,000 and 38,000 feet. Richardson regained control of the aircraft at 20,000 feet, but after three unsuccessful landing attempts at Hunter Air Force Base, the crew feared the heavy weapon would cause a conventional explosion during a crash landing. They received permission to jettison the 7,600-pound Mark 15 bomb, which contained 400 pounds of conventional high explosives. It was released at 7,200 feet while traveling at 200 knots. The B-47 subsequently made a successful emergency landing. The F-86 crashed east of Sylvania, Georgia, while Lt. Stewart parachuted to safety near Estill, South Carolina. Despite a ten-week search by the Navy and Air Force involving sonar and cable sweeps, the weapon was never located. The Air Force officially declared the bomb irretrievably lost on April 16, 1958.
Final Conclusions
The Air Force concluded that the collision resulted from the F-86 pilot's failure to see the B-47 during the night exercise. In subsequent reviews (2001 and 2004), the Department of Defense determined that the bomb is likely buried under 5 to 15 feet of silt. The official position remains that the weapon is safest left undisturbed, as recovery efforts could pose a risk of conventional detonation of the 400 pounds of high explosives contained within the casing. The Air Force maintains the nuclear capsule was not installed, precluding a nuclear blast.
Video Analysis
The H-Bomb Dropped in Shallow Water So It'd Be Found — A short overview of the 1958 mid-air collision between an F-86 Sabre and a B-47 Stratojet that led to the loss of a Mark 15 nuclear weapon near Tybee Island.
If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
Mark 15 Hydrogen Bomb
A thermonuclear weapon designed with a removable nuclear capsule (physics package) to prevent accidental nuclear detonation during transport or maneuvers.
Ejection Seat
The F-86 was equipped with an ejection system that allowed Lt. Stewart to safely exit the aircraft following the mid-air collision.
Interesting Facts
- 01The lost weapon is a Mark 15 hydrogen bomb, serial number 47782, weighing 7,600 pounds.
- 02The bomb contains 400 pounds of conventional high explosives and highly enriched uranium.
- 03The B-47 pilot, Col. Howard Richardson, was awarded the Distinguished Flying Cross for landing the damaged aircraft.
- 04The incident is classified as a 'Broken Arrow,' a U.S. military term for an accident involving a nuclear weapon that does not create the risk of nuclear war.
Safety Actions & Advisories
Nuclear Capsule Protocol
Source ↗Following the incident, the Air Force reinforced protocols regarding the transport of nuclear capsules. Strategic Air Command documents indicated that Alert Force test flights with older Mark 15 payloads were not authorized to carry nuclear capsules; such approval was only granted for 'sealed-pit' nuclear capsule weapons which began deployment in June 1958.
Known Controversies & Unanswered Questions
Nuclear Capsule Presence
Reference ↗While the Air Force and pilot Howard Richardson maintained the nuclear capsule was replaced by a lead dummy, 1966 congressional testimony by Assistant Secretary of Defense W.J. Howard claimed the bomb was a 'complete weapon' containing a plutonium trigger.