Probable cause
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.
NTSB analysis
The flight instructor in the helicopter reported that he was providing hovering autorotation training to a private pilot. The flight instructor reported that he rolled off the throttle to initiate the maneuver, and the private pilot "raised the collective too soon which resulted in the aircraft climbing." The rotor inertia decayed, and a main rotor blade struck the tailboom after the helicopter struck the ground. The helicopter sustained substantial damage to the tail rotor drive shaft.
The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Text from the NTSB. Open the NTSB docket for GAA17CA218 for the full record.
Event
- Date
- Apr 6, 2017
- Type
- Accident
- Place
- La Verne, California
- Nearest airport
- Brackett Field (POC)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Bell 206
- N-number
- N206SA
- Category
- Helicopter
- Year built
- 1973
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Instructional
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.