Probable cause
The pilot's failure to maintain main rotor RPM during a low altitude operation, which resulted in a loss of aircraft control and collision with terrain.
NTSB analysis
The pilot reported that while maneuvering at a low altitude over a machinery yard, he observed a low rotor rpm condition. When he lifted the collective the rpm continued to bleed off, which resulted in the helicopter yawing to the left. The pilot stated that he managed to get the helicopter back under control, but then entered the low rotor rpm condition a second time. Unable to keep the helicopter flying straight, the aircraft impacted up sloping terrain with its left skid, followed by the main rotor blades striking the ground. The helicopter sustained substantial damage due to the impact with terrain.
The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Text from the NTSB. Open the NTSB docket for WPR15CA128 for the full record.
Event
- Date
- Mar 14, 2015
- Type
- Accident
- Place
- Shelby, Montana
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Enstrom F28 - C
- N-number
- N5688N
- Category
- Helicopter
- Year built
- 1980
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Personal
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.