An army investigation of a 2009 helicopter crash at Wheeler Army Airfield that killed two pilots concluded that pilot error was the cause. The Honolulu Star Advertiser reports:
The trouble started within two seconds of the helicopter’s engine drive being disengaged from the rotors — the equivalent of putting a car transmission in neutral — in a test of the chopper’s ability to “autorotate.”
Pilots are trained to use the spinning momentum of the rotor and upward airflow to keep flying.
Instead, the Army OH-58D Kiowa Warrior quickly lost airspeed and plummeted from an altitude of 250 feet, according to an Army investigation. The two-seat chopper crashed at Wheeler Army Airfield, killing the pilots, Stanley Blane Hepfner, 29, and Jonathan Bryce Millward, 28, both chief warrant officers.
The accident investigation, obtained by the Star-Advertiser through the Freedom of Information Act, cites pilot error as the cause. The report says a drop in airspeed, a failure to abort the autorotation and a belated attempt to power back up sent the aircraft into a descent greater than 300 feet per minute into its own downwash.
“The pilots did not correct airspeed to stay within acceptable safety parameters,” the report said.
The Army is currently conducting an environmental assessment for a proposal to conduct helicopter training on Mauna Kea and Mauna Loa. Comments are due August 21, 2011. The Hawai’i State Department of Land and Natural Resources is the agency responsible for making the decision about granting a permit for the military training in a protected natural area.