SEA95LA183 · Beech V35A
Beech V35A · Accident: total loss of engine power (mechanical failure) en route
From Olympia Regional Airport (OLM) to Jefferson County International Airport (0S9)
Event
- NTSB case
- SEA95LA183
- 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
Beech V35A
- Aircraft type
- Beechcraft 35
- 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
- N8469N
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Olympia Regional Airport (OLM), Olympia, WATo Jefferson County International Airport (0S9), Port Townsend, WA
- 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
- Total 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, top overhaul, improper
- Engine installation, mounting bolt › Loose part/bolt/nut/clamp/etc
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During flight the pilot encountered an engine vibration, and shortly thereafter oil began appearing on the windscreen. While maneuvering toward suitable terrain the #2 cylinder departed the aircraft. A forced landing was made to a field. The aircraft impacted several fence posts, and the landing gear collapsed as it traversed rough/uneven terrain. Engine records documented a top overhaul of the engine approximately 172 hours before, during which the cylinders were removed and replaced. Metallurgical examination revealed that several cylinder hold-down nuts had backed off their bolts, or the bolts had separated in fatigue, allowing the cylinder to break free of the engine case. The mechanic reported using a silicone sealant between the cylinders and their respective engine case halves. Application of the uncalled-for sealant between the cylinders and case halves could result in a reduction or elimination of the preload torque applied to the through-bolts and hold-down studs.
Probable cause
the improper top overhaul of the engine and subsequent release of the cylinder hold-down nuts/breakage of hold-down and through-bolts. Factors contributing to the accident were the fence posts and rough/uneven terrain.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA95LA183
- Event ID
- 20001207X04383
- Case number
- SEA95LA183
- 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 1995-08-14.
- API snapshot SHA-256: c8fcc847ac1c46c2ba8c4412d32ad4e366edfab433da63a9487ab7a18099c173; retrieved 2026-09-21T22:06:49.957Z.