CHI99LA352 · Cessna 150M
Cessna 150M · Accident: loss of engine power en route
From Downtown Airport (3DW) to H21 · Camdenton, MO
Event
- NTSB case
- CHI99LA352
- 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
- N63668
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Downtown Airport (3DW), Springfield, MOTo H21 · Camdenton, MO
- 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
- Tree(s)
- 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, rocker arm/tappet › Fractured
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airplane was in level cruise flight at 2,500 feet msl, 85 knots, 2450 RPM, and heading 020 degrees toward Camdenton, Missouri, when the airplane's engine 'began running rough with RPM drop to 1500-1600.' The pilot said he applied carburetor heat, raised the nose of the airplane to minimize the altitude loss, and started heading toward Lebanon, Missouri. By leaning the mixture, the pilot was 'able to bring the engine RPM up to 1600-1700.' The pilot contacted the approach control at Springfield, Missouri, and informed them of their situation. The pilot said that the RPM began decreasing again. He placed the mixture to full rich, but noticed no change in performance. Then the engine stopped. The pilot said he maintained a 50-55 knot glide until the airplane impacted into a heavily wooded area. Examination of the airplane's engine showed that the shaft supporting the number 3 cylinder rocker arm had broken off. Examination of the remaining airplane systems showed no anomalies.
Probable cause
A loss of engine power due to a fractured shaft supporting the number three cylinder rocker arm. A factor relating to this accident was the trees.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI99LA352
- Event ID
- 20001212X19720
- Case number
- CHI99LA352
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1999-09-06.
- API snapshot SHA-256: 331f9b731efb8e5db2b968dded8fd979cc2eda533999d84df60fd61b1a83e710; retrieved 2026-09-22T14:12:19.203Z.