Amateur-built MINI-500 accident near Oshkosh, Wisconsin, July 27, 1995
On July 27, 1995 at about 2:30 pm local time, a amateur-built MINI-500 (helicopter), registered N500ZZ, was substantially damaged in an accident near Oshkosh, Wisconsin. It was a personal flight under general aviation rules (Part 91). 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 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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 27, 1995 · about 2:30 pm local time
- Place
- Oshkosh, Wisconsin · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built MINI-500
- Registration
- N500ZZ · no longer on the register · serial 0000
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
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
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: helicopter; instructor: instrument airplane; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 2,100 hours in all; 100 in this make and model; 50 in the last 90 days; 10 in the last 30 days; 1,600 as pilot in command; 50 on instruments
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 210 hours
- Last inspection: continuous airworthiness programme, July 25, 1995; 1 hours since
- Maximum gross weight: 840 lb
- Seats: 1
- Landing gear: fixed
- Engine: Rotax 582 (piston); 0 hours total
The flight
- Departed from: OSH WI at 2:20 pm
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 140° at 5 knots
- Visibility: 15 statute miles
- Sky: scat at 2,500 ft
- Temperature: 73°F (23°C), dew point 63°F (17°C)
- Altimeter: 29.00 inHg
- Observation at 1:45 pm from OSH, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N500ZZ the same tail number, which may have belonged to a different aircraft at the time
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.