FTW89LA144 · Cessna 172G
Cessna 172G · Accident: partial loss of engine power (mechanical failure) en route
From Mc Alester Regional Airport (MLC) to Mesquite Metro Airport (HQZ)
Event
- NTSB case
- FTW89LA144
- 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 172G
- 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
- N4377L
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Mc Alester Regional Airport (MLC), McAlester, OKTo Mesquite Metro Airport (HQZ), Mesquite, TX
- 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
- Partial loss of engine power (mechanical failure)
- 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 › Failure, total
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
DURING A NIGHT CROSS-COUNTRY FLIGHT, THE ENGINE LOST POWER AND DURING THE FORCED LANDING, THE AIRPLANE IMPACTED TREES AND THEN THE TERRAIN. DURING A PARTIAL TEARDOWN OF THE ENGINE, IT WAS FOUND THAT THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM SHAFT HAD BROKEN. THERE WAS ALSO A LARGE GAP BETWEEN THE ROCKER ARM AND THE EXHAUST VALVE STEM.
Probable cause
TOTAL FAILURE OF THE ENGINE ASSEMBLY/ROCKER ARM/TAPPET SHAFT.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW89LA144
- Event ID
- 20001213X29122
- Case number
- FTW89LA144
- 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 1989-08-05.
- API snapshot SHA-256: 97449126bde1a70df38a5236ca5509126e1f4d713d7185ea106948f687e4373b; retrieved 2026-09-23T07:18:02.686Z.