NTSB Factual Report

On April 12, 2013, about 1645 mountain standard time, a Bell OH-58C, N119FT, landed hard during a practice autorotation near the Deer Valley Airport, Phoenix, Arizona. The helicopter was being operated by, and registered to, the Maricopa County Sheriff's Office as a public-use flight. The certified flight instructor (CFI) and private pilot were not injured; the helicopter sustained substantial damage. The local instructional flight departed from Deer Valley about 0615. Visual meteorological conditions prevailed, and no flight plan had been filed.

After performing several maneuvers, the pilot was instructed by the CFI to complete the last practice autorotation of the day, which was intended to be a power recovery. With the helicopter about 500 feet above ground level (agl), the pilot initiated the maneuver by lowering the collective and rolling the throttle to idle power. As the helicopter descended below 60 feet agl, the CFI told the pilot to increase the engine power. The pilot had a delayed response to roll the throttle back to a full power setting and the low rotor horn began to sound.

The pilot further stated that he did not believe there was enough time for a power recovery and instead committed to performing a full touchdown. The helicopter touched down and slid about 6 feet. The skids dug into soft dirt and the nose pitched down, resulting in the main rotor blades severing the tailboom. The pilot reported that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation. He additionally reported that he thought the accident may have been prevented if he had more emergency procedures training, and if he had begun the power recovery at a higher altitude.

NTSB Probable Cause

The pilot receiving instruction's delay in adding power during a recovery from a practice autorotation.