WASHINGTON (CNN) -- The U.S. Air Force is grounding more than 100 planes used to support ground troops in Iraq and Afghanistan because of fatigue cracks in the wings, Air Force officials said Friday.





Aircraft like this A-10 Warthog provide close support to ground troops in Iraq and Afghanistan.





The officials said 127 A-10 Thunderbolt IIs, including some used in the United States, will be grounded until they are each inspected for the cracks.





"The inspections are a necessary step in addressing the risk associated with A-10 wing cracking, specifically with thin-skin wings. This risk is of great concern to the Air Force and is representative of a systemic problem for our aging Air Force fleet," the Air Force said.





The A-10 Thunderbolt II, nicknamed the "Warthog" because of its unique un-aerodynamic look, is one of the Air Force's older aircraft, having first been delivered to the service in 1975. The average age of the A-10 fleet is now 28 years, but the entire Air Force fleet has an average age of 25 years, according to Air Force statistics.





The Air Force has more than 400 A-10s in its fleet. The cracks in the older A-10 A-models and A-10 C-models were discovered at Hill Air Force Base in Utah during routine maintenance.





No A-10 has had an accident because of the cracks just discovered, according to Air Force officials.





The inspection of the 127 planes will give priority to the planes in the Iraq and Afghanistan theaters of battle, officials said.





The plane was designed as a tank killer, with a front-mounted Gatling gun that fires 30-mm armor-piercing ammunition capable of destroying a tank.





The planes are now primarily used in Iraq and Afghanistan to protect ground troops in close combat situations, flying low and slow and with the ability to target individuals hidden on mountainsides or rooftops.





Last year, the Air Force grounded hundreds of F-15 fighter jets after one fell apart during a training mission.





The culprit was a fatigued longeron, a part that holds the fuselage together. Numerous F-15s flying in Iraq and Afghanistan also were grounded until they were inspected, forcing the service to fly other aircraft in their place. The Navy was also asked to help cover the F-15 missions during the weeks they were grounded.
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