Probable cause
The pilot's failure to maintain control during landing.
NTSB analysis
The helicopter pilot performed a straight-in autorotation to runway 18 for a rotor rpm check. The engine rpm began to rapidly increase and the pilot rolled the throttle completely off and lowered collective. He reported that the left skid was coming off the ground and he applied full left cyclic and full down collective. The aircraft teetered and continued to roll right. The pilot stated that the helicopter had an articulated landing gear system. He said that the struts travel approximately seven to eight inches and “if only one side retracts it causes a ‘rolling moment’.” About 22 minutes before the accident, the recorded winds about seven nautical miles and 155 degrees from the accident site were 200 degrees at 14 knots with gusts to 32 knots. An examination of the accident helicopter’s controls and landing gear revealed no preexisting anomalies.
Text from the NTSB. Open the NTSB docket for CEN10CA371 for the full record.
Event
- Date
- Jul 4, 2010
- Type
- Accident
- Place
- East Troy, Wisconsin
- Nearest airport
- East Troy Municipal Airport (57C)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Brantly B-2B
- N-number
- N9011R
- Category
- Helicopter
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Flight test
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.