TUCSON - Thirty-four A-10 Thunderbolt II jets flown from Davis-Monthan Air Force Base have been grounded indefinitely after the Air Force found wing cracks in part of the service's aging fleet.
Had the problem gone undetected, it had the potential to cause wings to fall off, according to military aviation expert.
The Air Force on Friday ordered the immediate grounding of 130 of the 400 or so A-10 Thunderbolt II jets in use around the world.
Eighty-two of the A-10s are assigned to Davis-Monthan. Of those, 34 were grounded for inspection and repair in response to the Air Force order.
Tucson is home to the world's largest fleet of the aircraft, since Davis-Monthan is one of the nation's top training sites for A-10 pilots.
Introduced in 1975, the jets have surpassed their normal lifespan and have been refurbished to keep them in service. Production ceased in the mid-1980s.
The grounded A-10s all have thin-skin wings installed during original manufacture, the Air Force said.
Davis-Monthan wing commander Col. Paul Johnson said the discovery of wing cracks is a "serious issue" that must be addressed to protect pilots and the public.
Johnson said the Air Force is fortunate to have keen-eyed maintenance personnel who noticed the problem before it caused any mishaps.
Maintainers detected the wing cracks on A-10s undergoing upgrading and inspection at Hill Air Force Base in Utah.
Davis-Monthan will try to minimize the impact on trainees by using flight simulators, but "ultimately we may be forced to delay the graduation of some of our pilots," Johnson said.
Military aviation expert Peter B. Field, a retired Marine Corps pilot who has worked for major aircraft manufacturers, said "the Air Force is acting prudently" by grounding the jets.
He said a jet's wings flex with every flight and over time, the wings of older craft like the A-10, built before sturdier metal composites came into use, will begin to weaken along the flex lines.