The incident involved a B-52 flying from Minot Air Force Base in North Dakota to Barksdale Air Force Base in Louisiana with six nuclear weapons mounted under the craft's wing -- one of the worst known breaches of nuclear weapons handling procedures in decades.
The crew was reportedly unaware that the weapons were attached, and 36 hours passed before the missiles were accounted for, the Associated Press reported.
"We are making all appropriate changes to ensure this has a minimal chance of ever happening again," Air Force Secretary Michael W. Wynne told reporters after a briefing with Defense Secretary Robert Gates on the investigation into the incident, according to the AP.
The six-week Air Force probe found fault with several officers, who have been relieved of duty, Maj. Gen. Richard Newton, the Air Force deputy chief of staff for operation, said at the news conference. He said the 5th Bomb Group commander at Minot was relieved of command, among others. Newton did not name them.
Newton said the Aug. 29-30 incident involved an "unprecedented string of procedural errors."
A Defense Department press release said the Air Force relieved three commanders of duty and disciplined an undisclosed number of others in connection with the warhead incident.
After arriving at Barksdale, the B-52 sat for hours loaded with the missiles before the breach was realized -- meaning a total of 36 hours passed before the missiles were properly secured, officials have said, according to the AP.
The erroneous flight was so serious that it required President Bush and Gates to be swiftly informed.
Newton said the 5th Bomb Wing, which operates the B-52 in question, has been "decertified from its wartime mission."
He also said the August incident was isolated but a result of a problem at the two air bases.
"There has been an erosion of adherence to weapons handling standards at Minot Air Force Base and Barksdale Air Force Base," Newton said, news agencies reported.