CEN22LA402

The flight instructor reported that he and the commercial pilot receiving instruction were practicing simulated autorotations with power recovery. During one autorotation, as the helicopter was flared at the conclusion of the autorotation, the flight instructor increased the engine throttle and waited for the pilot receiving instruction to increase collective. When he did not feel the collective control move, the flight instructor pulled up on the collective, but the helicopter struck the ground before it could ascend. The pilot receiving instruction stated that during the flare, he did not feel the engine power increase like he had felt on previous autorotations; the helicopter sank fast and struck the ground. The main rotor of the helicopter severed the tail boom during the hard landing. Examination of the helicopter and a subsequent engine test run in a test cell did not reveal any anomalies that would explain a loss of engine power. Based on the available evidence, the accident was the result of the pilot receiving instruction’s failure to increase collective at the conclusion of the autorotation and the flight instructor’s delayed remedial response, which resulted in a hard landing.

On August 29, 2022, about 2155 central daylight time, an MD Helicopters 369E, N1576F, was substantially damaged when it was involved in an accident at the William P. Hobby Airport, Houston, TX. The flight instructor and pilot receiving instruction were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight was conducted by a flight instructor and a commercial pilot who was receiving instruction. The fight instructor reported that he and the pilot receiving instruction were conducting a simulated power recovery autorotation with a 90° turn. The maneuver was started at 800 ft above ground level (agl) and between 75 and 80 knots (kts) airspeed, and the instructor stated that he was commanding the throttle while the pilot receiving instruction commanded the cyclic, anti-torque, and collective controls. The instructor reduced the throttle and the pilot receiving instruction reduced airspeed to about 60-65 kts. When the helicopter descended to 300 ft agl, the flight instructor increased engine throttle and the pilot receiving instruction continued the autorotation, flared, and leveled the helicopter about 10 ft agl. The flight instructor waited for the pilot receiving instruction to increase collective, but he did not feel the collective control move, so he pulled up on the collective, but the helicopter struck the ground before it could ascend. The helicopter then slid to a stop and the flight instructor pulled the emergency fuel cutoff to shut down the engine. After exiting the helicopter, the instructor saw that the tail boom had separated from the helicopter. The pilot receiving instruction reported that he had set the helicopter up for a simulated autorotation with a 90° turn and power recovery. He counted down from 3 to begin the autorotation. The throttle was rolled to idle, and the pilot receiving instruction lowered the collective and depressed right pedal. He pitched the helicopter to maintain 60 kts while making a 90° turn to align with the runway. He maintained rotor speed by slightly raising and lowering the collective control. As the helicopter descended through about 150 ft agl, he began to flare. He felt the throttle increase but did not feel the power increase like he had felt on previous autorotations. The helicopter sank fast and struck the runway, skidding to a stop. He noted that the flight instructor pulled the fuel cutoff to stop the engine. Examination of the helicopter and a subsequent engine test run in a test cell did not reveal any anomalies that would explain a loss of engine power.