“The possibility of an accidental nuclear explosion taking place is essentially negligible,” the director of nuclear safety at Kirtland Air Force Base told CBS News. The Atomic Energy Commission said much the same thing to the New York Times, claiming the odds were “so remote that they can be ruled out completely.” But a number of scientists and engineers at Sandia didn’t share that degree of optimism. Bob Peurifoy felt uneasy that a simple, low-voltage signal, lasting a few seconds, was still being used to arm hydrogen bombs. That kind of signal dated back to the days of Thomas Edison — and it could come from a lot of places as a B-52 fell apart. It could come from a short circuit during an otherwise uneventful flight. Peurifoy thought that a more complicated signal — a unique series of electrical pulses — could prevent a bomb from being armed accidentally. Transmitted between the ready/safe switch in the cockpit and the nuclear weapon in the bomb bay, it would operate much like a secret code, alternating long and short pulses in a pattern that fate, bad luck, or even Mother Nature couldn’t randomly generate.
Another engineer, Thomas Brumleve, criticized the air of overconfidence at Sandia, the overemphasis on reliability, the faith that an accidental detonation could never happen. “But suppose some important aspect of nuclear safety has been overlooked,” Brumleve wrote in a 1967 report. “The nation, and indeed the world, will want to know who was responsible, how it could have happened, and why it wasn’t prevented.”
On January 21, 1968, a B-52 was serving as the Thule monitor. For hours it flew a “bowtie” pattern at thirty-five thousand feet, heading back and forth above the ballistic missile early warning complex in western Greenland. One of the copilots, Major Alfred D’Amario, Jr., had stuffed three cloth-covered, foam-rubber cushions beneath the instructor navigator’s seat, and someone later put a fourth one under it, keeping the cushions wedged in place with a small metal box. The cushions might ease the discomfort of a long, tedious mission. About five hours into the flight, the crew noticed that the heat wasn’t working properly. The cockpit felt too cold, and so D’Amario turned on a system that pulled air from the engine manifold into the cabin. The air was hot, about 428 degrees Fahrenheit. It ignited the cushions, which were blocking a vent under the seat.
The radar navigator, Major Frank F. Hopkins, thought he smelled something burning. It smelled like burning rubber. The crew looked for the source of the smoke, found it, sprayed the cushions with fire extinguishers, but couldn’t put out the fire. The pilot, Captain John Haug, asked the control tower at Thule for permission to conduct an emergency landing. As Haug started the descent, Hopkins opened the sextant port, a small hole in the fuselage, to let out smoke. The navigator, Captain Curtis R. Criss, tried to smother the burning cushions with a duffle bag. But the flames spread, and the smoke in the cockpit became so thick that Haug could barely see the instrument panel. He told Thule that the fire was out of control. Moments later, the plane lost all its power.
The crew would have to bail out into some harsh weather. The temperature that day in western Greenland was -23 degrees Fahrenheit; the windchill made it feel like -44. Haug wanted to get as close as possible to Thule and increase the odds of his crew’s survival — without crashing the B-52 into the base. Although their mission was simply to keep an eye on Thule and make sure that it still existed, the plane carried four Mark 28 bombs.
Haug stayed with the plane until everyone was out and then ejected, just four miles short of the runway. The B-52 passed right over Thule, made a 180-degree turn, flew another few miles, and slammed into the ice of Bylot Sound. The explosion caught most of the men on the base by surprise, shaking the buildings and lighting up the sky. It was about four thirty in the afternoon but completely dark outside. The sun hadn’t been seen in Thule for almost two months, since late November. Except for a brief period of dim light in the afternoon, the snow-covered landscape around the base seemed dark as night. SAC headquarters was notified, for the first time, about the fire on the plane, the crash, and the explosion. The command post at Thule had no idea if there were any survivors. And then Major D’Amario walked into one of the aircraft hangars and asked to use a phone. His parachute had deposited him near a runway. D’Amario told the base commander that at least six of the seven crew members had bailed out. Security police officers split into teams and got into trackmasters to find them, driving the large vehicles out of the base. Helicopters soon joined the search. In the Arctic weather, every minute counted: uncovered skin could become frostbitten within two.
