LAX98FA068 · Cessna 182P
Cessna 182P · Accident: partial loss of engine power (mechanical failure) en route
From San Carlos Airport (SQL) to Soledad, CA
Event
- NTSB case
- LAX98FA068
- 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
- 1 · 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 182P
- Aircraft type
- Cessna 182
- 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
- N8158M
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From San Carlos Airport (SQL), San Carlos, CATo Soledad, CA
- 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
- Utility pole
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Other maintenance personnel › Maintenance, inspection, inadequate
- Other maintenance personnel › Maintenance, top overhaul, improper
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During a night-time flight in marginal VFR conditions, the pilot radioed approach control that his aircraft's engine had begun running rough, losing power, and he was having difficulty maintaining altitude. Approach control vectored the pilot 14 miles back to the airport where he had previously completed an instrument approach. The pilot reported the runway in sight, however, the aircraft crashed on final approach 2 miles from the runway. A witness reported hearing the aircraft's engine as it approached, followed by 5 seconds of silence, and then the sound of impact. An annual inspection was completed on the aircraft about 2 weeks before the accident and this was believed to be the owner's first flight after the inspection. During the inspection, the Nos. 1, 3, and 4 cylinders were removed from the engine and repaired. Postaccident examination of the engine revealed that one of the two valve keepers had not been reinstalled on the No. 3 cylinder exhaust valve resulting in asymmetric loading of the remaining keeper. When that keeper fractured, the exhaust valve was released and entered the combustion chamber of the No. 3 cylinder where it contacted the piston. The consequential damage fractured the Nos. 3 and 4 pistons, the Nos. 3 and 4 connecting rods, and the crankcase.
Probable cause
A loss of engine power due to a missing valve keeper. Also causal was the failure by engine maintenance personnel during engine top overhaul to install the second valve keeper in the No. 3 cylinder exhaust valve and the failure of inspection personnel to detect the improper assembly.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX98FA068
- Event ID
- 20001211X09458
- Case number
- LAX98FA068
- 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 1998-01-10.
- API snapshot SHA-256: e250d8c8550785003227f18d290040904bdb1bb593d90098d1aade5ad8851f63; retrieved 2026-09-20T22:42:24.718Z.