WASHINGTON — Air Force weapons officers assigned to secure nuclear warheads failed on five occasions to examine a bundle of cruise missiles headed to a B-52 bomber in North Dakota, leading the plane's crew to unknowingly fly six nuclear-armed missiles across the country.
That August flight, the first known incident in which the military lost track of its nuclear weapons since the dawn of the atomic age, lasted nearly three hours, until the bomber landed at Barksdale Air Force Base in northern Louisiana.
But according to an Air Force investigation presented to Defense Secretary Robert M. Gates on Friday, the nuclear weapons sat on a plane on the runway at Minot Air Force Base in North Dakota for nearly 24 hours without ground crews noticing the warheads had been moved out of a secured shelter.
"This was an unacceptable mistake," said Air Force Secretary Michael W. Wynne at a Pentagon news conference. "We would really like to ensure it never happens again."
For decades, it has been military policy to never discuss the movement or deployment of the nuclear arsenal. But Wynne said the accident was so serious that he ordered an exception so the mistakes could be made public.
On Aug. 29, North Dakota crew members were supposed to load 12 unarmed cruise missiles in two bundles under the B-52's wings to be taken to Louisiana to be decommissioned. But in what the Air Force has ruled were five separate mistakes, six missiles contained nuclear warheads.
According to the investigation, the chain of errors began the day before the flight when Air Force officers failed to inspect five bundles of cruise missiles inside a secure nuclear weapons hangar at Minot. Some missiles in the hangar have nuclear warheads, some have dummy warheads, and others have neither, officials said.
An inspection would have revealed that one of the bundles contained six missiles with nuclear warheads, investigators said.
"They grabbed the wrong ones," said Maj. Gen. Richard Newton, the Air Force's deputy chief of staff in charge of operations.
After that, four other checks built into procedures for checking the weapons were overlooked, allowing the plane to take off Aug. 30 with crew members unaware that they were carrying enough destructive power to wipe out several cities.
Newton said that even though the nuclear missiles were hanging on the B-52's wings overnight without anyone knowing they were missing, the investigation found that the Minot's tarmac was secure enough that the military was never at risk of losing control of the warheads.
