An Air Force safety board investigation has been completed into a Dec. 22 midair collision between a C-17 cargo carrier and a refueling tanker off O'ahu, but the results won't be released, officials said.

"The (safety board) results are for internal Air Force use only and are not releasable to the public," a state Department of Defense statement said. "(A safety board) is convened for the purpose of investigating an incident and making recommendations on how to prevent future incidents from occurring under similar circumstances."

The contact with a Hawai'i Air National Guard KC-135R refueling tanker occurred 200 miles off O'ahu during night refueling practice with Hickam Air Force Base's Col. William "Goose" Changose at the controls of the C-17.

Both planes received minor damage and landed safely, officials said. The C-17 was flown in from the Mainland for training.

Changose said he was seeking requalification as an instructor pilot. He had planned to pilot the first of eight C-17s for Hawai'i into Hickam today with Brig. Gen. Peter Pawling, commander of the 154th Wing of the Hawai'i Air National Guard.

Changose grounded himself after the collision, pending the conclusion of the inquiry. Changose and Pawling are expected to be on today's C-17 flight into Hickam, but neither will be flying.

The safety board team, made up of Air National Guard and active duty Air Force members from Pacific and Mainland bases, is in the process of briefing the chain of command on the results.

Changose last week said, "If the results say I did something wrong ... I don't think there would be any punitive (action) because I know we flew the flight clean. But more retraining, that sort of stuff (would happen)."

Reach William Cole at wcole@honoluluadvertiser.com.