What happened
On February 18, 2020, an Aerospatiale AS350 operated by the Hillsborough County Sheriffs Office was conducting a training flight near Tampa, Florida. During the flight, a flight instructor directed the pilot receiving instruction to perform an autorotation involving a 180-degree turn and a power recovery.
As the aircraft passed the departure end of the runway, the instructor moved the throttle lever from the fly position to idle. During the maneuver, the pilot overshot the runway and aligned the helicopter with a parallel taxiway. To correct the position, the crew decided to abort the maneuver and attempt a go-around.
While the student pilot maintained control of the aircraft, the instructor moved the throttle lever from the idle position aft toward the off position before moving it forward back to the fly position. This action caused the engine to experience a total loss of power. Despite attempts by the instructor to adjust the throttle, the engine did not recover.
As the helicopter descended, the student pilot requested that the instructor take control. The instructor took the controls and performed a power-off autorotation. The helicopter landed on the taxiway, skidded approximately 180 feet, exited the taxiway onto the adjacent grass, and came to rest in a drainage ditch. There were no injuries resulting from the accident.
The investigation
An FAA inspector examined the N188FS at the accident site and found substantial damage to the left anti-vibrator mount beam. The flight instructor reported that there were no mechanical failures or malfunctions prior to the accident that would have prevented normal operation.