A bird strike caused a deadly helicopter crash at Camp Pendleton last year that killed two Marines, according to a Marine Corps investigation.

The AH-1W Cobra attack helicopter collided Sept. 19 with a red-tailed hawk that had a wing span of about 4 feet and probably weighed about 3 pounds, according to a report obtained by U-T San Diego (http://bit.ly/KxrFT1 ).

Both pilots onboard, Capt. Jeffrey Bland, 37, and 1st Lt. Thomas Heitmann, 27, were killed in the crash.

The hawk hit the top of the helicopter and damaged the pitch change link, according to the report. Almost immediately after impact, vibrations in the main rotor caused the rotor and top of the transmission to separate from the aircraft.

The helicopter fell in three pieces to the ground, and the wreckage ignited a brush fire that burned more than 120 acres.

The event was "unavoidable," and after it occurred, the helicopter "was not recoverable," according to the report.

Bland's mother told the newspaper that the family is shocked to hear about the bird strike.

"We know it happens to jets, with birds getting into the engines. But we never thought about a bird bringing down a helicopter," said Janet Bland.

The report recommends studying a redesign of the copter's transmission fairings and pitch change links to make the aircraft less vulnerable to bird strikes.


Information from: U-T San Diego, http://www.utsandiego.com