NYC99LA146 · Hiller UH-12C
Hiller UH-12C · Accident: loss of engine power en route
From I12 · Sidney, OH to Defiance Memorial Airport (DFI)
Event
- NTSB case
- NYC99LA146
- 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
- 0
- 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-12C
- 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
- N57CR
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From I12 · Sidney, OHTo Defiance Memorial Airport (DFI), Defiance, OH
- 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 91: General Aviation
- 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
- En route · cruise
- First occurrenceThe 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
- Loss of engine power
- 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
- Fuel starvation
- 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
- Fuel system, line › Blocked(total)
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
After maintenance was completed to change an engine, the pilot conducted a test flight, paid the bill, and departed. About 30 minutes into the flight, the pilot felt the helicopter shutter, and noticed a partial loss of power, accompanied by engine surges. The pilot executed an autorotation to an open field, followed by a hard landing. No pre impact failures or malfunctions were identified with the engine or engine accessories. After the accident the helicopter had approximately 25 gallons of fuel onboard. Power was applied to the auxiliary fuel pump, it rotated, but no fuel was expelled. The pump was examined, and no failures or malfunctions were identified. Also, no breaks in the fuel system were identified. The engine driven fuel pump, and auxiliary fuel pump share a common fuel filter, and plumbing from the fuel tanks.
Probable cause
A blocked fuel line, from an unknown object, that resulted in fuel starvation, and total loss of engine power. A factor in the accident was the pilot's failure to maintain rotor rpm during the autorotation.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record NYC99LA146
- Event ID
- 20001212X19098
- Case number
- NYC99LA146
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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. 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: 58b2ac4ee317ebc722c0551c785639a826e18f86432a04bfe993abe7a95b424b; retrieved 2026-09-22T14:49:28.672Z.