Rotorcraft Development CORP OH-58A+ accident near Waterloo, Illinois, May 7, 2017
On May 7, 2017 at about 7:50 pm local time, a 1971 Rotorcraft Development CORP OH-58A+ (helicopter), registered N993YC, was substantially damaged in an accident during maneuvering (low-alt flying) near Waterloo, Illinois. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s failure to see and avoid transmission wires while maneuvering at a low altitude.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 7, 2017 · about 7:50 pm local time
- Place
- Waterloo, Illinois · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Rotorcraft Development CORP OH-58A+ NO SERIES, built 1971
- Registration
- N993YC · no longer on the register · serial 71-20367
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Miscellaneous/other during maneuvering (low-alt flying) defining event
- Collision with terrain or object (not controlled flight into terrain) during maneuvering (low-alt flying)
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring environment › Pilot
- cause Environmental issues › Physical environment › Object/animal/substance › Wire › Awareness of condition
- cause Environmental issues › Physical environment › Object/animal/substance › Wire › Effect on operation
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instructor: instrument helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 5,556 hours in all; 456 in this make and model; 31 in the last 90 days; 31 in the last 30 days; 5,450 as pilot in command
- Last flight review: October 1, 2016
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 4,580.7 hours
- Last inspection: annual inspection, March 15, 2017
- Maximum gross weight: 2,114 lb
- Seats: 2
- Landing gear: fixed
- Engine: Allison T63-A-720 (turboshaft); 0 hours total
The flight
- Departed from: 1IL4 Millstadt IL at 11:30 am
- Flight plan: not recorded
Weather at the time
- Light: daylight
- Wind: from 350° at 10 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 75°F (24°C), dew point 37°F (3°C)
- Altimeter: 30.01 inHg
- Observation at 7:53 pm from KCPS, 17 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on June 14, 2017. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 8 pages | View Download |
| 2 | Accident Photos (Courtesy of FAA) | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.