On 6 Apr 2017, a BELL 206 B operated by Havasu Heli Flights, LLC was involved in an aviation accident near La Verne, CA. No fatalities were reported. Investigators recorded the probable cause as: The pilot’s early increased application of the collective during a simulated hovering autorotation, which resulted in a loss of rotor rpm and subsequent main rotor blade strike of the tailboom. This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.
During hovering autorotation training, a private pilot raised the collective too soon, causing the helicopter to climb, then strike the ground. The tailboom was struck by a main rotor blade, and the tail rotor drive shaft sustained substantial damage.
Incident Overview
A flight instructor was providing hovering autorotation training to a private pilot in a helicopter. The instructor reported that he reduced the throttle to initiate the maneuver. The private pilot then raised the collective too soon, which resulted in the helicopter climbing. As rotor inertia decayed, the helicopter struck the ground. Following the ground strike, a main rotor blade struck the tailboom.
Damage Assessment
The helicopter sustained substantial damage to the tail rotor drive shaft. According to the pilot, there were no preaccident mechanical malfunctions or failures that would have precluded normal operation.
Training Context
The maneuver being practiced was a hovering autorotation, a training exercise typically used to practice engine failure recovery at low altitude. The flight instructor was present to guide the private pilot through the procedure.