The Air Force has found no significant environmental impact for a plan to base 20 F-22A Raptor fighters at Hickam Air Force Base. As a result, the service concluded that a lengthier environmental impact statement is not needed under federal law.

The Air Force is in the design phase for the basing, but the environmental review completion is another step toward starting construction on $146.4 million in projects around 2009 for the Raptors, an official said.

The stealth fighters, which are the Air Force's most advanced weapons system, will replace F-15 Eagles at Hickam, and are expected to start arriving in 2011.

The aircraft would be used for the air defense of Hawai'i as well as for worldwide missions.

The Raptors can reach supersonic speed without afterburners, are highly maneuverable and are almost invisible to radar. The aircraft, whose angular shape and internal weapons bays contribute to a radar signature the size of a bird, is one of the costliest fighters ever at more than $339 million a copy, including research, development and testing.

The Hawai'i Air National Guard will be the first Guard unit to "own" the Raptors, while the active duty Air Force at Hickam will be an associate unit and also fly and maintain the aircraft.

Plans call for the Raptors to occupy the same southern portion of Hickam that's used for the aging F-15 fighters. An estimated 20 facilities would be constructed or renovated over a five-year period.

According to an environmental review, Honolulu International Airport supports about 880 daily flights, of which 5 percent to 6 percent are military. Military average daily operations would increase from 53 with the F-15s to 65 with the F-22A squadron.

Four locations in the Pacific Rim were considered as bases for the Raptors including Hickam; Eielson Air Force Base in Alaska; Elmendorf Air Force Base in Alaska; and Andersen Air Force Base on Guam.

The environmental review says the Hickam F-22A squadron and an operational F-22A wing at Elmendorf "would provide a western complement" to the eastern U.S.-based first F-22A wing at Langley Air Force Base in Virginia.

The Hawai'i Air Guard F-15s, in addition to having an air defense role for Hawai'i, deployed to Saudi Arabia in 2000 and conducted combat missions over southern Iraq.

Reach William Cole at wcole@honoluluadvertiser.com.