CHI95FA242 · Revolution Helicopter MINI-500
Revolution Helicopter MINI-500 · Accident: total loss of engine power (mechanical failure) en route
From Wittman Regional Airport (OSH) to an unrecorded destination
Event
- NTSB case
- CHI95FA242
- 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
Revolution Helicopter MINI-500
- Aircraft type
- Revolution MINI-500
- 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
- N500ZZ
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Wittman Regional Airport (OSH), WITo 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 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
- Total loss of engine power (mechanical failure)
- 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
- Landing gear, skid assembly › Incorrect
- Production/design personnel › Acft/equip, inadequate design
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The amateur-built helicopter was conducting a demonstration flight during the annual EAA convention. During the first flight after re-jetting of the carburetor, the helicopter experienced a total loss of engine power. During the autorotation into a crop field, the helicopter was substantially damaged when the skid shoes caught in the terrain, failing the left skid and fracturing the shoe on that skid. Subsequent examination of the engine revealed that the rear piston had seized in the cylinder. The owner of the company which produces the helicopter stated that the re-jetting of the carburetor was made in an attempt to achieve what were thought to be correct readings in main rotor RPM and EGT after replacement of both gauges. The company owner attributed the piston seizure to the re-jetting. The skid shoes were new and had been tested only on concrete. The owner said that the design contributed to the damage to the helicopter.
Probable cause
the inadequate design of the helicopter skid shoes. Factors related to the accident were: false indications of rotor rpm and EGT which led to seizure of the piston.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI95FA242
- Event ID
- 20001207X03882
- Case number
- CHI95FA242
- 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: 2afac74c441d49ef5287932ca14bfb4a0dd1cf414240296781861fcffb45c410; retrieved 2026-09-22T23:32:55.176Z.