CHI98FA286 · Monocoupe Aircraft 70
Monocoupe Aircraft 70 · Accident: loss of engine power during initial climb
From 8D1 to Wittman Regional Airport (OSH)
Event
- NTSB case
- CHI98FA286
- 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
Monocoupe Aircraft 70
- Aircraft type
- Monocoupe 70
- Category
- Airplane
- 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
- NC6740
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From 8D1To Wittman Regional Airport (OSH), Oshkosh, WI
- 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
- Initial climb
- 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
- 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, carburetor › Ice
- Pilot in command › Carburetor heat, not used
- Pilot in command › Preflight planning/preparation, inadequate
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot said that after takeoff, and over the departure end of the runway, the engine began to run rough and lose power. The pilot said that he leaned the mixture. It seemed to help, but then the engine began to run rough again. The pilot turned back toward the airport with the intent of landing on the grassy field near the runway. Then the engine quit. The pilot stretched his glide so that he could clear trees on the edge of a corn field. The pilot tried to force land the airplane in the corn field. The airplane touched down in the corn and flipped over. Examination of the airplane revealed no anomalies. According to the Department of Transportation/Federal Aviation Administration/CT-82/44 Publication: Light Aircraft Piston Engine Carburetor Ice Detector/Warning Device Sensitivity/Effectiveness, June 1982, Carburetor Icing Probability Chart; the temperature (72 degrees Fahrenheit) and dew point (52 degrees Fahrenheit) at the time the airplane lost power, places the probability for carburetor icing in the 'serious icing at glide power' area of the chart.
Probable cause
The pilot's failure to use carburetor heat in weather conditions conducive to carburetor icing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI98FA286
- Event ID
- 20001211X10481
- Case number
- CHI98FA286
- 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: e4e069c7659e8ffe98dd269cc95730782d527b57f8a2d28bb326d0792948817e; retrieved 2026-09-21T20:44:17.130Z.