A Marine helicopter crash that killed a crew chief and injured five others last summer at Camp Pendleton was caused by debris likely hitting its tail rotor, along with a design flaw and pilot error, a Marine investigation concluded.
A report said debris such as a stray bolt probably hit the tail rotor, causing structural failure and destroying the helicopter's drive train, according to documents obtained by U-T San Diego (http://bit.ly/GVg5Lp ) under the Freedom of Information Act.
After losing tail rotor thrust, the pilot of the hovering UH-1Y Huey aggravated the problem by trying to push the craft forward instead of reducing the throttle, the report said.
However, the report said that appeared to be a training gap rather than negligence and the investigating officer recommended against any administrative action for the aircrew, operations personnel or maintenance staff.
The report noted that in an unofficial study after the crash using a simulator, only two of 30 pilots responded correctly and 23 of them would have crashed.
The investigation also said the design of the Bell helicopter contributed to the crash because it made it hard to spot debris around the drive shaft and lacked protective barriers.
The crew was practicing a landing on July 6 when the helicopter yawed to the right, began to spin and crashed on its side in a ravine. The instructor crew chief was pinned under a door. Sgt. Trevor Cook, 25, of Lyndonville, N.Y., died at the scene.
A fire erupted and the other crew members escaped. The $20 million aircraft was declared a total loss.
Cook's widow, Amanda Cook, told U-T San Diego that she was comforted by the report's conclusion that her husband died within seconds of the crash.
"My biggest thing was to know if Trevor suffered. Thankfully, he didn't," she said.
"It was a freak accident, a mechanical failure that does not happen every day. He was just in the wrong place," said Cook's father, David Cook.
His son was an Afghanistan veteran.
"In his seven short years in the Marine Corps he did more for his country than most people will do in their entire life," Cook said. "He is well-missed of course, but we are proud of who he was and what he stood for."
The crash was one of several involving San Diego County Marines in the past year.
Last month, seven Marines _ six of them based at Pendleton _ were killed when two helicopters collided during training in the desert along the California-Arizona border.
Information from: U-T San Diego, http://www.utsandiego.com