FTW02LA021 · Cessna 152
Cessna 152 · Accident: partial loss of engine power (mechanical failure) en route
From 98F · Duncan, OK to Wiley Post Airport (PWA)
Event
- NTSB case
- FTW02LA021
- 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
- Unknown
- 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 152
- Aircraft type
- Cessna 152
- 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
- N67797
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From 98F · Duncan, OKTo Wiley Post Airport (PWA), Bethany, OK
- 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)
- 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
- Miscellaneous, bolt/nut/fastener/clamp/spring › Loose
- Other maintenance personnel › Maintenance, adjustment, improper
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The private pilot reported that during a night cross-country flight, the engine began to lose power. The pilot could not maintain altitude to reach the airport, and therefore, elected to land in a field. The pilot landed the airplane in a field where it impacted a barbed wire fence. An FAA airworthiness inspector examined the engine with the assistance of an aircraft mechanic. The FAA inspector reported that they removed the #2 cylinder's rocker arm cover and noted that "the exhaust valve adjuster 'lock nut' had loosened and come completely off." Review of a maintenance record entry dated May 21, 2000, revealed that the #2 cylinder had been removed, repaired, and reinstalled at an aircraft total time of 825.0 hours. On August 13, 2001, the airplane and engine underwent their most recent 100-hour inspection at an aircraft and engine total time of 1,077.0 hours. The aircraft total time at the time of the accident is unknown. According to the engine operator's manual, persons installing pushrods for a cylinder are instructed to recheck the tappet clearance after run-in and lock the valve clearance adjusting screw in place with the locknut.
Probable cause
the mechanic's failure to properly lock the exhaust valve's clearance adjusting screw locknut, which resulted in a loose nut, disabling of the exhaust valve pushrod, and a partial loss of engine power while in cruise flight. A contributing factor was the night light conditions for the forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW02LA021
- Event ID
- 20011029X02154
- Case number
- FTW02LA021
- 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 2001-10-26.
- API snapshot SHA-256: 8f3062491ff95d28122399f8d79adde04ee34f39dbbbae004c0aea6bcea1db96; retrieved 2026-09-22T11:29:29.455Z.