As the bomber’s sole bomb descended upon the city below, a feeling of unbelief and dread filled the hearts of the plane’s crew. Part of their apprehension was due to the unexpected damage caused by the bomb’s release. Another part of their dread had to do with the fact that they had just deployed the most powerful weapon ever created. To top it all off, this horrifying Armageddon-inducing bomb had just been released over Albuquerque, New Mexico entirely by accident. Aside from a handful of military personnel, the astonishing story of how nearly 200,000 people faced instant annihilation would remain classified for nearly 30 years.

The date was May 22, 1957. A B-36 bomber, its crew of 13, and its payload were on approach to land at Kirtland Air Force Base in Albuquerque. The payload was just one bomb, but there was nothing ordinary about it. It was a 42,000-pound, 10-megaton hydrogen bomb, codenamed Mark 17.

Mark 17 Hydrogen bomb.

Mark 17 was the largest weapon the world had ever seen. It was the first droppable thermonuclear device, because of its massive size, the B-36 was the only aircraft capable of ferrying it from Biggs Air Force Base in Texas to its intended destination in New Mexico.

A number of safety procedures were put in place during the transportation of such a deadly device. Standard operating procedure on all such flights called for the manual removal of the locking pin designed to prevent the accidental in-flight release of bombs to allow emergency jettisoning of weapons, if necessary, during takeoffs and landings.

The procedure was not simple. It involved having a crew member climb into the bomb bay and lean over the body of the bomb at the beginning and end of each flight to set and later remove the large U-2 pin. To do this, the crew member had to hang over the 25-foot long bomb, roughly the size and shape of a whale, to manage the pin. On this particular day, 1st Lt. Bob Carp was assigned the task.

B-36 Bomber

At 11:49 a.m., with the plane descending to 1,700 feet and making its final approach before landing at Kirtland, Carp began moving back toward the bomb. The plane was nearly four miles south of the airfield, and landing conditions were normal as Carp reached across the deadly payload.

What happened next is in dispute. Previously published reports describe Carp reaching up to regain his balance and pull himself into the cockpit, and being unexpectedly jolted as the huge bomber bounced through a pocket of turbulent air. Trying to avoid a fall, according to this version, he grabbed for the nearest hand-hold, a lever that immediately gave way under his weight. Carp maintains that a “defectively designed” manual release mechanism had been accidentally pulled into release mode by a snag in his long cable. Regardless of which event is true, it was responsible for triggering a rapid succession of events: the giant bomb under his feet instantly sank, pulled free from its mooring and tore its way straight downward, directly through the closed bomb bay doors, ripping them away and opening a gaping, terrifying hole in the bottom of the plane; and the bomber itself; suddenly released from the weight of its 21-ton payload, bounded upward, gaining more than 1,500 feet of altitude in seconds before the startled pilot could regain control.

The next words to reach the cockpit were more terrifying than the experience of the plane unexpectedly shooting upward. “Bombs away!” screamed one nearby crewman, his eyes wide with shock as he peered in-to the newly opened void where the weapon and the man had been. A crew member later recalled that it was a few seconds later that Carp, his face, “whiter than any sheet you ever saw,” slowly pulled himself out of the remaining bomb bay, yelling above the deafening roar of jet engines and rushing air, “I didn’t touch anything! I didn’t touch anything!”

Radio Operator George Houston, seated nearby, alertly responded by sending a distress call to the Kirtland tower. To the stunned operator, he reported the ominous news: “We’ve dropped a hydrogen bomb!”

The bomb itself plummeted downward with frightening speed, the 1,700 foot drop far too short for its parachutes to slow its descent. Long before the plane could pull away, the weapon smashed into the nearly barren mesa, where a lone New Mexico cow peacefully munched sagebrush, oblivious to the source and immediacy of its own destruction. There was an earth-shattering explosion as the weapon detonated.

Fortunately, only the bomb’s conventional explosives — those necessary to start the nuclear chain reaction — were triggered by the fall. The resultant explosion created a crater 12 feet deep and 25 feet across in uninhabited land owned by the University of New Mexico. The unlucky cow was the only casualty of the mishap.

Field Command, a division of the Armed Forces Special Weapons Project, swept into the area and conducted recovery and clean-up operations. The U.S. Government paid the University of New Mexico for the damage to its land and hauled away truckloads of contaminated soil, without reporting the exact nature of the incident.

The investigation went quickly, largely due to the fact that most of the experts who were needed to conduct the investigation were there at Kirtland. They concluded the incident was accidental, and no disciplinary action was taken against anyone involved. They filed their report, and the case remained sealed for nearly three decades.

Only in 1986, in response to a Freedom of Information Act request filed by the news media, were the terrifying details acknowledged and released to the public. For nearly 30 years, the residents of Albuquerque lived in blissful ignorance of how close they came to annihilation on that fateful day.

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