Airmen and F-22 Raptor fighters recently returned to Joint Base Pearl Harbor-Hickam from their first training deployment since the stealth jets began to arrive in Hawaii in 2010.

Hawaii Air National Guardsmen and active-duty Air Force personnel, as well as four F-22 Raptor fighter jets, took part in the Air Force’s air-to-ground weapons evaluation program, known as Combat Hammer, at Hill Air Force Base in Utah.

Combat Hammer is used to evaluate the effectiveness of air-to-ground weapons systems, the Hawaii Air National Guard said. Inert (nonexplosive) bombs were dropped in the exercise.

The two-week exercise from July 30 to Aug. 9 provided a number of firsts for the Hawaii Air National Guard. In addition to being the first training deployment for Hawaii’s F-22 Raptors, it was also the first time the Hawaii Air National Guard has trained in an air-to-ground capacity.

Combat Hammer took place over the Utah Test and Training Range.

The Hawaii Air National Guard, which flies and maintains the Raptors with the active-duty Air Force, has 14 of the jets. More are expected to arrive in Hawaii in the near future to round out the squadron of 20.

The Air Force lifted restrictions on long-duration flights for deployments, aircraft deliveries and repositioning of the aircraft on July 24 after it said it had found the source of pilot breathing problems that had plagued the expensive jets.

The Air Force determined that a faulty valve caused an upper part of a pressure suit used at high altitudes to remain inflated when it should have deflated, causing pressure on the chest and breathing problems.

The Air Force removed a canister filter from the oxygen delivery system that restricted airflow, and is making other improvements to delivery hoses.

The determined there were 36 hypoxia incidents — pilots not getting enough oxygen — as of July 2, with 21 classified as unexplained.

A Hawaii Air National Guard F-22 Raptor pilot declared an "in-flight emergency" July 6 after experi- encing momentary dizziness, but landed safely at Hickam.

It was the first reported case of hypoxia-like symptoms experienced by a Hawaii-based pilot, the Hawaii National Guard said.

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