Probable cause
The pilot's failure to maintain clearance from the ground-support vehicle during landing.
NTSB analysis
The pilot reported that he was unable to activate the motorized spray system after arriving at the field to be sprayed. He returned to the departure location in order to troubleshoot the inoperative spray system. As he maneuvered the helicopter to land next to a ground-support vehicle, the main rotor system impacted a landing platform installed on top of the vehicle. The pilot reported that there were no preimpact mechanical malfunctions or failures that would have precluded normal operation of the helicopter. The wind near the time of the accident was reported as calm. In the absence of any mechanical malfunctions or adverse atmospheric conditions, the pilot should have been able to maintain proper distance from the known obstacle.
Text from the NTSB. Open the NTSB docket for CEN12LA443 for the full record.
Event
- Date
- Jul 14, 2012
- Type
- Accident
- Place
- Red Oak, Iowa
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Robinson Helicopter Company R44 II
- N-number
- N556MM
- Category
- Helicopter
- Damage
- Substantial
- Operating rule
- Part 137 (agricultural)
- Purpose of flight
- Aerial application
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.