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.
The Air Force said Friday it would punish 70 airmen involved in the accidental flight following an investigation that found widespread disregard for the rules on handling such munitions.
"There has been an erosion of adherence to weapons-handling standards at Minot Air Force Base and Barksdale Air Force Base," said Maj. Gen. Richard Newton, the Air Force deputy chief of staff for operations.
Newton was announcing the results of a six-week probe into the Aug. 29-30 incident in which the B-52 was inadvertently armed with six nuclear-tipped cruise missiles and flown from Minot in North Dakota to Barksdale in Louisiana without anyone noticing the mistake for more than a day.
That August flight, the first known incident in which the U.S. 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," Air Force Secretary Michael Wynne said at a Pentagon news conference. "We would really like to ensure it never happens again."
For decades, it has been military policy never to discuss the movement or deployment of the U.S. nuclear arsenal. But Wynne said the Aug. 30 accident was so serious that he ordered an exception to the policy so the mistakes could be made public.
On Aug. 29, crews in North Dakota were supposed to load 12 unarmed cruise missiles in two bundles under the wings of the B-52 to be taken to Louisiana to be decommissioned. But as a result of what the Air Force has ruled were five errors, six of the 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 and some do not, while some have dummy warheads, 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 ignored or overlooked, allowing the plane to take off Aug. 30 with crew members unaware that they were carrying enough destructive power to wipe out several U.S. cities.
A main reason for the error was that crews had decided not to follow a complex schedule under which the status of the missiles is tracked while they are disarmed, loaded, moved and so on, one official said on condition of anonymity because he was not authorized to speak on the record.
The airmen replaced the schedule with their own "informal" system, he said, though he didn't say why they did that nor how long they had been doing it their own way.
Newton insisted 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 tarmac at Minot was secure enough that the military was never at risk of losing control of the warheads.
The cruise missiles were supposed to be transported to Barksdale without warheads as part of a treaty that requires the missiles to be mothballed. Newton said the warheads are normally taken out of the missiles in the Minot hangar before the missiles are assigned to a B-52 for transport.
The Air Force did not realize the warheads had been moved until airmen began taking them off the B-52 at Barksdale.
Newton declined to say what explanation the Minot airmen gave investigators for their repeated failure to check the warheads once they left the secured hangar, saying only that there was inattention and "an erosion of adherence to weapons-handling standards."
One Air Force officer familiar with the investigation noted that the flight occurred just before Labor Day weekend. Another official noted that until the Air Force was given the mission to mothball the cruise missiles earlier this year, it had not handled airborne nuclear weapons for more than a decade, meaning most of the airmen lacked experience with the procedures.
The Air Force has fired four colonels who oversaw aircraft and weapons operations at Minot and Barksdale, and other more junior personnel also had been disciplined, Newton said.
In addition, the wing has been "decertified from its wartime mission," Newton said.
The case has been handed over to a three-star general who will review the findings and determine whether any should face court-martial proceedings.
Information for this article was contritbuted by The Washington Post and The Associated Press.