LAX07LA040 · Stinson 108-1
Stinson 108-1 · Accident: partial loss of engine power (mechanical failure) en route
From Reid-Hillview Airport of Santa Clara County (RHV) to San Jose, CA
Event
- NTSB case
- LAX07LA040
- 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
Stinson 108-1
- Aircraft type
- Stinson 108
- 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
- N97949
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Reid-Hillview Airport of Santa Clara County (RHV), San Jose, CATo San Jose, 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)
- 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, valve, exhaust › Seized
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
According to the pilot, he was flying above hilly terrain southeast of the airport when he heard a loud bang, followed by a violent vibration coming from the engine. The pilot added that the engine did not experience a total loss of power, but performed poorly due to the severe vibration. The pilot reduced the throttle and the vibration subsided, but when he added more throttle the violent vibration returned. The pilot then decided that it was unsafe to continue the flight and began searching for a place to land. He made a forced landing in a pasture, which was uneventful until one of the main landing gear contacted a "deviation" in the ground. The airplane nosed over and came to rest inverted. In a phone interview with the investigator-in-charge, a mechanic, who recovered the wreckage, reported that he examined the engine and discovered that the number 3 cylinder exhaust valve was stuck. The corresponding push rod tube was also bent, and the number 3 connecting rod was still intact.
Probable cause
Partial loss of engine power due to a seized exhaust valve during cruise flight. Rough terrain at the forced landing site was a contributing factor.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX07LA040
- Event ID
- 20061124X01711
- Case number
- LAX07LA040
- 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, coordinates. 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: 50f05162d3111be7c674dbf05028ac6760a28dbdf7b56d84d99f62a51e8af95c; retrieved 2026-09-22T04:13:23.573Z.