ALBUQUERQUE, N.M. (AP) — An Air Force squadron responsible for maintaining an estimated 2,000 nuclear weapons at a New Mexico base was re-certified Friday after passing a surprise inspection that resulted from the unit's shortcomings last fall.

Kirtland Air Force Base officials said the 898th Munitions Squadron received a "ready" rating after a team from the Air Force Materiel Command at Wright-Patterson Air Force Base in Ohio spent the week looking into the unit, which maintains an underground weapons cache.

"It would have been rather embarrassing and problematic if they hadn't passed," said Hans Kristensen, who monitors nuclear weapons issues at the Federation of American Scientists in Washington, D.C.

The squadron lost its certification Jan. 27 after failing a November inspection. The commander of the Nuclear Weapons Center at the base, Brig. Gen. Everett Thomas, requested the decertification, but the Air Force said the reliability and accountability of the nuclear stockpile was never affected.

Air Force officials blamed administrative problems, such as the handling of paperwork and documentation. The Air Force reassigned five noncommissioned officers in the fallout from the failed exam.

"You can have good guys out there handling the tools, but if management of the project doesn't work, that can be a problem," Kristensen said. "I don't think this instance was so much a safety issue as much as it was a proficiency issue."

Kirtland officials said in a statement the corrected problems included "documentation, maintenance processes, management and technical skills."

Two other units also failed inspections earlier this year: the 341st Missile Wing and 16th Munitions Squadron, both at Malmstrom Air Force Base in Montana. The units passed a reinspection last month.

The failed inspections in New Mexico and Montana raised concerns because they reflected new episodes of questionable oversight after the military took steps to correct similar issues.

In August 2007, nuclear cruise missiles at Minot Air Force Base, N.D., were mistakenly loaded onto a B-52 bomber and flown to a Louisiana base. The foul-up cost a colonel his command and was cited by Defense Secretary Robert Gates as contributing to his decision to fire Air Force Chief of Staff Gen. Michael Moseley and Air Force Secretary Michael Wynne.

In November 2003, the Navy said a weapons facility in Bremerton, Wash., was decertified after a ladder was mistakenly left inside a missile tube on the Trident submarine USS Georgia while a nuclear missile was being lifted from the tube.

And in March 2008, the United States mistakenly shipped to Taiwan four electrical fuses designed for use on intercontinental nuclear ballistic missiles. The items, which were returned to the U.S., were not nuclear materials.

Two months later, the Air Force began a rigorous effort to strengthen its system of ensuring proper handling of nuclear weapons.