Accident Details
On September 24, 2012, about 1600 Pacific daylight time, a McDonnell Douglas 369FF helicopter, registration N911BL, sustained substantial damage during a hard landing after a practice autorotation at North Las Vegas Airport, Las Vegas, Nevada. The helicopter was registered to the Las Vegas Metropolitan Police Department and was being operated as a public aircraft training flight. The two pilots, who both held flight instructor certificates, sustained minor injuries.
Flight Information
The local training flight had originated from North Las Vegas Airport approximately 30 minutes before the accident. Visual meteorological conditions prevailed at the time, and no flight plan had been filed.
Pilot Statements
The pilot-in-command (PIC)/pilot-giving-instruction reported that he and the pilot receiving instruction were alternately practicing autorotations. He decided to demonstrate a 270-degree autorotation to the touchdown point on taxiway Zulu. The maneuver began on a 180-degree heading, 800 feet above ground, at an airspeed of 85 knots. As the helicopter crossed the intended touchdown point, the PIC rolled the throttle back to initiate the autorotation. He estimated the wind to be from 180 to 230 degrees at 15 knots, gusting to 26 knots. During a left turn, he reported increasing his bank angle to maintain ground reference to the touchdown point due to a tailwind. The pilot receiving instruction reported that moments later, the helicopter was in a high rate of descent with decreasing airspeed.
Impact and Damage
The helicopter impacted terrain in a tail-low attitude. Subsequently, the tail boom separated from the fuselage, the helicopter rolled onto its right side, and the right landing skid support structure folded under the fuselage.
Weather Conditions
At 1605, the reported wind at North Las Vegas Airport, elevation 2,205 feet, was 270 degrees at 13 knots, gusting to 22 knots. The calculated density altitude, using a barometric pressure of 29.77 inches of mercury, was 5,116 feet.