CHI08CA252 · Hiller UH-12E
Hiller UH-12E · Accident: low altitude operation/event while maneuvering
From Cokato, MN to an unrecorded destination
Event
- NTSB case
- CHI08CA252
- 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
Hiller UH-12E
- Aircraft type
- Hiller UH-12
- 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
- N945HA
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Cokato, MNTo not recorded
- Aircraft age
- Not recorded
- 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 · low-altitude flying
- 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
- Low altitude operation/event
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Wire
- 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
- Aircraft › Aircraft oper/perf/capability
- Personnel issues › Action/decision
- Personnel issues › Task performance
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 reported he made three passes over the fields that he was going to spray. He stated he noticed a power line pole that had a transformer cover on it and what appeared to be a wire covering running up the pole. This led the pilot to believe that the power lines in the area were buried. The pilot then landed and loaded the chemicals. He stated that after taking off with the load, he flew one more pass to look for power lines and still did not see any. He stated that during the first swath run, the helicopter contacted power lines. The helicopter initially pitched nose up and to the right. The pilot stated he pushed the nose down and to the left, but the power lines wrapped around the control tubes and tail rotor. The helicopter then entered a descending spin. The pilot stated he pulled back to flatten the descent just prior to the helicopter contacting the ground.
Probable cause
The pilot did not visually identify and maintain clearance with the power lines, and the pilot's inability to maintain control of the helicopter once it contacted the power lines. Factors associated with the accident were the low altitude operations being conducted and the power lines.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI08CA252
- Event ID
- 20080916X01474
- Case number
- CHI08CA252
- 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: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 00f1265de48e143a7e85fe9c972acf1f1c74776ce853a6363d50b161819c3105; retrieved 2026-09-15T10:13:44.337Z.