Information Supplied by Nuclear Weapons Historian Chuck Hansen
The researchers for this site were advised by nuclear physicist Ralph Lapp to contact nuclear-weapons historian Chuck Hansen for information about the Goldsboro incident. Hansen generously forwarded the following text to us on 12 October 2000. This material makes its public debut on this page, and will be published in forthcoming versions of Hansen's CD-ROM, The Swords of Armageddon.
"Hyperlinked" word definitions are provided where possible.
Note to readers: In forwarding this material to us, Hansen included the following notations at the end of his sources list of some problems and conflicts contained within the source documents. We felt they warranted prominent placement:
"The January 24, 1961 Loper to Anderson letter states that the free-falling weapon suffered a one-point detonation on impact in his January 26 letter to Anderson, Loper corrected this statement and noted that a one-point detonation had not occurred. The MK 39s dropped near Goldsboro have been misidentified and mischaracterized in almost every published popular account of this incident. The bombs were not "24 megaton weapons," as most commonly described. The terms "nuclear capsule" and "tritium injection" are mutually exclusive. The Goldsboro weapons were most likely sealed pit MK 39s; "nuclear capsule" were only used on weapons with insertable cores (including early MK 39 mods). Sealed pit MK 39s began entering stockpile in March 1957."
January 24, 1961 / B-52 / Goldsboro, North Carolina
During a B-52G airborne alert mission 15 miles north of Seymour Johnson AFB, a fire began as a result of a major leak in a wing fuel cell which had caused the loss of 37,000 lbs. of fuel in two minutes. The fire and resultant explosion caused structural failure of the aircraft's right wing at an altitude of 8,000 feet after the crew had bailed out. This in turn resulted in two unarmed MK 39 weapons without nuclear capsule separating from the bomber during airframe breakup between 10,000 and 2,000 feet. The two bombs fell to earth near Goldsboro, North Carolina, about one mile from the crash site and 13 miles from Seymour Johnson. Five of the eight B-52 crew members survived. Wreckage of the aircraft was scattered over a wide area of approximately two square miles near Faro, North Carolina.
During the breakup of the airframe, three of four arming safety devices on one bomb were actuated, including arming wires pulled out, the pulse generator actuated, the explosive actuator fired, a timer run down, all contacts of the differential pressure switch closed, and the low and high voltage thermal batteries actuated. The arm-safe remained in a "safe" position and the rotary safing switch was not operated. The X-unit was not charged, nor was tritium injected into the pit.
These actions resulted in the bomb's warhead going through all of its arming sequence, including 100-foot diameter retardation parachute deployment, activation of internal timing mechanisms, development of high voltage in the firing system, etc. However, since the fourth arming device -- the pilot's arm/safe switch -- was not activated, the warhead did not complete its arming sequence. This MK 39 descended by parachute and consequently suffered only minor damage when it impacted the ground, penetrating about 18 inches and deforming the frangible bomb casing nose assembly. The weapon remained in an upright position with its parachute hanging in a tree about a mile from the main aircraft wreckage field. (Figure VIII-4)
The second MK 39 bomb fell free and broke apart upon impact with the sandy clay earth about 500 yards from the main aircraft wreckage and three-quarters of a mile from the impact point of the first bomb. This weapon made a visible surface crater about eight feet in diameter and six feet deep. No explosion occurred, although this weapon was also partially armed upon release from the aircraft and further by closure of an arming switch upon impact. A high voltage switch was not closed, so this bomb also did not arm completely. This weapon's fuzing and firing sequence underwent all of the actions of the first bomb, with the exception that the timer ran for only 12 to 15 seconds; only two contacts of the differential pressure switch closed; the high voltage thermal battery was not actuated; and the rotary safing switch was destroyed on impact. The nose crystals in both weapons, used for salvage fuzing, were crushed.
Upon impact, both the primary and secondary of the free-falling bomb smashed through the frangible nose of the weapon and penetrated farther into the waterlogged farmland. The tail of the bomb was located approximately 22 feet below ground surface. Excavation began immediately after the crash, around 1:30 PM on January 24, but was hindered by freezing weather, water in the hole, and the presence of unexploded HE. During the remainder of January 24, manual and mechanical digging reached a depth of eight feet, where a portion of the main body section and pieces of the nose section were found.
The following day, at a depth of 12 feet, the top of the parachute pack was exposed. Adverse weather and a rising water table hindered recovery operations on January 26; however, digging reached 15 feet where the parachute pack, a section of the nose, and pieces of the primary and HE were recovered.
By January 28, digging had reached a depth of 18 feet and detonators, two arm/safe switches, trajectory arming device, more pieces of HE and the primary, and a tritium bottle were found. One of the arm/safe switches was found in the "armed" position.
By February 7, digging had resulted in the excavation of a crater 42 feet deep and 200 feet in diameter. Recovery operations were canceled at this time because of cave-ins, freezing weather, equipment limitations, and rising water. The recovered bomb parts, including an undamaged tritium reservoir and the weapon's afterbody, were taken to the AEC's Medina Base near San Antonio, Texas. Figure VIII-5 shows the weapon afterbody being removed from the buried bomb in the muddy pit.
Uncontrollable flooding of the crater caused by a high local water table made further excavation impractical despite 14 pumps removing a combined total of 6,000 gallons of water per hour and further retrieval work was halted on May 25. Calculations based on the weight and configuration of the secondary, impact angle and velocity, and soil composition placed the missing bomb component at a depth of 180+/-10 feet. The probable minimum estimated cost of recovery was in the neighborhood of $500,000.
The Air Force subsequently purchased an easement to prevent digging in the vicinity of the point of impact. The missing weapon secondary was never located. (During a later accident, LASL told the Air Force that thermonuclear weapon secondaries were "virtually indestructible.") There was no detectable radiation in the area.
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Last Updated: 27 November 2000