CHI98LA267 · Cessna 150M
Langa Air Academy Cessna 150M · Accident: loss of engine power en route
From General Wayne A. Downing Peoria International Airport (PIA) to St Louis Regional Airport (ALN)
Event
- NTSB case
- CHI98LA267
- 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
Cessna 150M
- Aircraft type
- Cessna 150
- 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
- N9251U
- Operator
- Langa Air Academy
- Onboard fatalities
- Unknown
- Route
- From General Wayne A. Downing Peoria International Airport (PIA), Peoria, ILTo St Louis Regional Airport (ALN), Alton, IL
- 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
- 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
- Engine assembly, cylinder › Compression
- Engine assembly, valve, exhaust › Open
- Pilot in command › Directional control, not maintained
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that the engine began to vibrate and run very rough at an altitude of 4500' MSL. He noticed an immediate loss of power and was unable to maintain altitude. The pilot then cycled the magnetos, increased the mixture control to full rich, confirmed that the fuel selector was in the 'ON' position and applied carburetor heat, all of which had no effect. Being uncertain as to the cause of the power loss and concerned that the engine would quit operating, the pilot declared a mayday and requested vectors. At the time the pilot made visual contact with the airport, the aircraft was at an altitude of 1100' MSL. The pilot chose to land on runway 09 even though there would be a quartering tailwind present upon landing. During the landing rollout, the pilot felt the tail swing to the left at which time the airplane departed the runway toward right, into the grass and impacted a concrete culvert, separated the right main wheel and slid to a stop. The pilot stated that landing was made with full flaps. Examination of the engine revealed that the number three cylinder had a compression of 35/80 and the number four exhaust valve was stuck in the full open position.
Probable cause
Loss of engine power due to an open exhaust valve and low cylinder compression. A related factor was the tailwind.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI98LA267
- Event ID
- 20001211X10518
- Case number
- CHI98LA267
- 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: 2b26f208f646473760f1fd0a8c736d5585f26f5889168c9101de78b89631196a; retrieved 2026-09-22T17:23:18.029Z.