Investigation Summary
The B-52G was participating in Operation Chrome Dome, a Cold War mission requiring continuous airborne alerts with nuclear-armed bombers. During the second refueling of the mission, the B-52 approached the KC-135 at a speed higher than standard procedure. The aircraft was commanded by Major Charles Wendorf, with Captain Larry Messinger serving as the instructor pilot; both were at the controls during the refueling attempt. Wendorf later noted that although they were overrunning the tanker, the boom operator did not issue a 'break away' call. The resulting impact saw the refueling nozzle strike the B-52's upper fuselage, severing a longeron and the left wing. The KC-135's fuel load ignited immediately, destroying the aircraft. The B-52 disintegrated, dropping four B28FI thermonuclear bombs. Two bombs hit the ground near Palomares, where their high-explosive triggers detonated, scattering radioactive plutonium dust. A third bomb landed relatively intact in a dry riverbed, and the fourth fell into the Mediterranean Sea, triggering a massive 80-day naval search and recovery operation involving the submersible DSV Alvin and local fisherman Francisco Simo Orts.
Final Conclusions
The accident was caused by a mid-air collision during aerial refueling due to an excessive closure rate by the B-52G. The incident led to significant radioactive contamination and was a major factor in the termination of Operation Chrome Dome in 1968. While 1,750 tons of soil were initially removed, residual plutonium remains a concern. Despite a 2015 agreement between the U.S. and Spain for further remediation, significant cleanup of the remaining contaminated land is still pending as of 2025.
Photographic Evidence (1)
Video Analysis
Palomares incident sees a B-52 mid-air collision and dropping four nuclear bombs — A detailed look at the 17th January 1966 Palomares incident involving a B-52 mid-air collision and the subsequent loss of four nuclear weapons.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
United States Air Force N/A — Boeing B-52G Stratofortress · 58-0256
United States Air Force N/A — Boeing KC-135A Stratotanker · 61-0273
Systems & Failure Modes
Refueling Boom
A rigid, telescoping tube used to transfer fuel from a tanker to a receiver aircraft; in this case, the nozzle struck and compromised the B-52's structural integrity.
B28FI Thermonuclear Bomb
A Cold War era nuclear weapon; two units suffered 'non-nuclear' detonations of their conventional high-explosive components upon ground impact.
Interesting Facts
- 01The B-52 was carrying four B28FI Mod 2 Y1 thermonuclear bombs.
- 02The collision occurred at an altitude of 31,000 feet over the Mediterranean coast.
- 03Approximately 1,750 tons of radioactive soil were removed and shipped to the United States for disposal.
- 04The accident prompted Spain to ban U.S. flights carrying nuclear weapons over its territory.
- 05Navy diver Carl Brashear lost his lower left leg during the recovery operations for the lost bomb.
- 06The search for the fourth bomb was one of the first successful applications of Bayesian search theory in a salvage operation, led by Dr. John P. Craven.
Safety Actions & Advisories
Termination of Operation Chrome Dome
The Palomares accident, followed by the 1968 Thule crash, led to the permanent cessation of continuous airborne nuclear alert missions.
Overflight Restrictions
Spain prohibited the United States from flying nuclear-armed aircraft through Spanish airspace following the incident.
Known Controversies & Unanswered Questions
Veteran Compensation and Health Monitoring
Reference ↗Clean-up personnel have faced long-term health issues and legal battles with the Department of Veterans Affairs over radiation exposure, leading to a class-action lawsuit certified in 2019.