WPR23LA107 · Bell OH-58A
Bell OH-58A · Accident while maneuvering
From Tri-Rotor Ag Services Airport (AZ25) to an unrecorded destination
Event
- NTSB case
- WPR23LA107
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Bell OH-58A
- Aircraft type
- Bell OH-58
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N36FA
- Operator
- Tri Rotor Spray & Chemical
- Onboard fatalities
- Unknown
- Route
- From Tri-Rotor Ag Services Airport (AZ25), Somerton, AZTo not recorded
- Aircraft age
- About 55 years (built 1968)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 137: Agricultural
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering · hover
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Unknown or undetermined
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Not determined › Not determined
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot of the helicopter was conducting an agricultural application flight in dark night conditions. He stated that, after completing the chemical application, he landed on the load truck and the hopper was filled with 50 gallons of water to rinse out the applicator system. The pilot departed from the load truck toward an open field about 200 yards away. The pilot stated that, while maneuvering about 40 ft above ground level when the spray tank was almost empty, the helicopter began to “bounce and tilt in all directions,” then “fish-tailed” before the engine lost total power. The pilot stated that he was unable to judge the helicopter’s height above the ground, and the helicopter subsequently landed hard, during which the main rotor blades severed the tail rotor drive shaft. Postaccident examination of the helicopter and engine revealed no anomalies or malfunctions that would have precluded normal operation. About 5 gallons of fuel was found in the fuel tank, 1.4 gallons of which was unusable. No engine abnormalities were found during an engine run on a test stand. Based on the available information, the reason for the loss of engine power could not be determined.
Probable cause
A total loss of engine power for reasons that could not be determined.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR23LA107
- Event ID
- 20230207106695
- Case number
- WPR23LA107
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status, coordinates, cause areas. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2023-02-07.
- API snapshot SHA-256: f9693d1221a02f62c04af04f1a4a75a27c12206ad62eff903e70d712f532cef9; retrieved 2026-09-16T17:19:19.269Z.