Probable cause
The pilot’s failure to see and avoid transmission wires while maneuvering at a low altitude.
NTSB analysis
The helicopter pilot reported that, while maneuvering at a low altitude for an agricultural application flight, he began flying along the north side of the intended spraying field. He added that he was paying attention to the trees along the field to maintain adequate clearance. He further added that the main rotor blades struck transmission wires and that he then heard a "high pitch sound" coming from the engine and the rpm decrease. The nose pitched up, and the helicopter impacted the ground and rolled onto its right side.
The helicopter sustained substantial damage to the fuselage and empennage.
The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
The pilot reported that he had noticed the transmission wires earlier in flight but that he later forgot where they were located.
Text from the NTSB. Open the NTSB docket for GAA17CA265 for the full record.
Event
- Date
- May 7, 2017
- Type
- Accident
- Place
- Waterloo, Illinois
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Rotorcraft Development Corp OH-58A+
- N-number
- N993YC
- Category
- Helicopter
- Year built
- 1971
- 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.