Bell 206B N536T accident near Decatur, Texas

Probable cause

The flight instructor’s improper recovery from a practice autorotation, which resulted in a hard landing.

NTSB analysis

The pilot-rated student and flight instructor were conducting a helicopter proficiency flight. After about 2 hours of flight and completing a series of maneuvers, which included straight-in and 180-degee autorotations, the instructor began to demonstrate another 180-degree autorotation. The instructor reported that, when the helicopter was at 200 ft at the start of the approach, the rotor speed was in the mid to low section of the green band. At the beginning of the flare, he tried to roll in full throttle, but he felt resistance, and he didn't get the power restored in time. He then attempted to level the helicopter to avoid a tail strike. The pilot receiving instruction reported that the instructor was at the controls and that, when the helicopter was at 100 ft, he noticed that the rotor speed was at a minimum and that the rate of closure was slow. He thought they were going to be short, so he called for power and reached for the throttle to confirm it was fully on. The helicopter landed hard and slid to a stop just off the runway. Examination of the helicopter and throttle system did not reveal any abnormalities.

Text from the NTSB. Open the NTSB docket for CEN14LA296 for the full record.