NTSB Identification: LAX04LA273.
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Accident occurred Monday, July 19, 2004 in Big Bear City, CA
Probable Cause Approval Date: 12/20/2005
Aircraft: Agusta A119, registration: N928KR
Injuries: 7 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
While maneuvering during an intentional low altitude and low airspeed flight over upsloping high mountainous terrain, the helicopter lost effective translational lift while turning about 50 feet above ground level and the helicopter entered an uncontrolled descent and impacted hard on the mountainside. The purpose of the sales demonstration flight was to provide the prospective buyer (county sheriff) an opportunity to evaluate the helicopter in reconnaissance type missions over mountainous terrain. To facilitate the evaluation, the demonstration pilot allowed the sheriff's pilot to fly the helicopter over a route chosen by the sheriff. The sheriff's pilot had no flying experience in the model of helicopter. The flight was unremarkable until the sheriff's pilot allowed the helicopter's main rotor speed to drop while decreasing the forward airspeed to 20 knots. The demonstration pilot did not take the controls from the sheriff's pilot in time to avert the uncontrolled descent into the 8,800-foot mean sea level terrain. At the time, the outside air temperature was about +20 degrees Celsius, and the density altitude was over 11,000 feet. According to the helicopter manufacturer's performance data for hovering out of ground effect, the helicopter was about 500 pounds too heavy to hover at this altitude at the helicopter's gross weight.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the pilot-passenger's failure to maintain an adequate airspeed above translational lift and to maintain adequate main rotor rpm while performing a maneuvering turn under high density altitude conditions and over high mountainous terrain, which resulted in an uncontrolled descent. Also causal was the pilot-in-command's inadequate supervision of the pilot-passenger and his delayed initiation of remedial action. Full narrative available
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