Today in 2007 at Minot AFB, North Dakota, munitions crews accidentally loaded a B-52H bomber with six Advanced Cruise Missiles, each armed with a live W80-1 nuclear warhead with a variable yield of 5-150 kilotons. The plane sat on the tarmac overnight without any special guards. 
Early the next morning, before takeoff, the B-52's radar navigator closely inspected only the 6 missiles on the right-wing pylon, all of which properly carried dummy warheads. The pilot signed the manifest listing 12 unarmed ACMs as cargo without conducting a final verification.
This was supposed to be a routine fight supporting the USAF's March 2007 decision to retire the ACM by ferrying the missiles stored at Minot to Barksdale AFB, Louisiana, for disposal (by August 2007, more than 200 unarmed ACMs had been safely transported to Barksdale). It wasn't.
The B-52 departed Minot at 8:40am and landed at Barksdale at 11:23am (both local times). The crew signed out and went to lunch. Again, there were no special guards. It wasn't until 8:30pm, when munitions crews began unloading the aircraft, that one person noticed something amiss.
Approximately 36 hours had elapsed from the time the armed missiles were mistakenly removed from their bunker at Minot to the time an airman noticed them on the B-52 in Barksdale. In all that time, no one realized they were missing or that they were left unguarded at both bases.
As a result of this BENT SPEAR, 7 senior USAF officers were relieved of their commands or positions and reassigned, 65 airmen lost their Personnel Reliability Program certifications to work with nuclear weapons, and the secretary of the Air Force and USAF chief of staff resigned.
