MIA94LA103 · Cessna 172RG
Cessna 172RG · Accident: partial loss of engine power (mechanical failure) during initial climb
Event
- NTSB case
- MIA94LA103
- 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 172RG
- Aircraft type
- Cessna 172
- 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
- N9781B
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo 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
- 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
- Partial 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
- Company maintenance personnel › Maintenance, service bulletin/letter, not performed
- Engine assembly, push rod › Bent
- Engine assembly, valve, exhaust › Seized
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The aircraft's engine lost partial power during climb after takeoff. The aircraft would not maintain altitude and a forced landing was made in a wooded area. Postcrash examination of the engine indicated the No. 4 exhaust valve had stuck and the exhaust valve pushrod was bent. No other engine malfunctions were noted. Textron Lycoming Engines issued mandatory service bulletin 388B on May 13, 1992, requiring the testing of the exhaust valve clearances each 400 flight hours on aircraft. The logbook records for N9781B did not have any entries showing compliance with service bulletin 388B.
Probable cause
The failure of the aircraft operator to comply with engine manufacturers service bulletins which resulted in improper inspection of exhaust valves and subsequent sticking of the no. 4 exhaust valve.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record MIA94LA103
- Event ID
- 20001206X00960
- Case number
- MIA94LA103
- 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: f0c13635b65e3a2b3b2466e3c31431d2179213ba40b1453b0374442b485e0a89; retrieved 2026-09-23T01:13:40.265Z.