LAX95LA125 · Mooney M20J
Mooney M20J · Accident: total loss of engine power (mechanical failure) en route
From San Gabriel Valley Airport (EMT) to Santa Barbara Municipal Airport (SBA)
Event
- NTSB case
- LAX95LA125
- 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
Mooney M20J
- Aircraft type
- Mooney M20
- 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
- N11385
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From San Gabriel Valley Airport (EMT), El Monte, CATo Santa Barbara Municipal Airport (SBA), Santa Barbara, 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 · climb to 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
- Fluid, oil › Exhaustion
- Lubricating system, oil gasket › Not installed
- Other maintenance personnel › Maintenance, overhaul, major, improper
- Other maintenance personnel › Procedures/directives, not followed
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
AFTER OVERHAUL AT AN ENGINE FACILITY, THE ENGINE WAS INSTALLED IN THE AIRPLANE BY A MAINTENANCE SHOP. THE ENGINE WAS GROUND RUN FOR ONLY 40 MINS INSTEAD OF THE 2 HRS AND 25 MINS SPECIFIED BY LYCOMING. DURING THE TEST, AN OIL LEAK WAS FOUND IN THE AREA OF THE PROP GOVERNOR OIL PRESSURE LINE FITTING. THE FITTING WAS TIGHTENED AND THE AIRCRAFT PUT IN THE OWNER'S HANGAR. ON THE FIRST FLIGHT BY THE OWNER, THE ENGINE SEIZED AFTER 15 MINS. THE AIRCRAFT COLLIDED WITH OBSTRUCTIONS DURING THE FORCED LANDING. A LARGE SMEAR OF OIL WAS FOUND ON THE FUSELAGE BELLY AND LEFT SIDE. THE DISASSEMBLY OF THE ENGINE REVEALED DAMAGE CONSISTENT WITH LACK OF LUBRICATION DUE TO OIL EXHAUSTION. THE DIP STICK WAS IN PLACE AND ALL OIL LINES AND FITTINGS WERE TIGHT AND NOT LEAKING. WHEN THE PROP GOVERNOR WAS REMOVED ONLY A MS9144-01 SCREEN GASKET WAS FOUND INSTALLED. A RAISED CHANNEL AND OIL TRAIL WAS OBSERVED FROM A PRESSURE PORT IN THE GOVERNOR PAD UNDER THE GASKET TO THE PAD EDGE. LYCOMING'S PARTS MANUAL AND SERVICE INSTRUCTIONS SPECIFY THAT THIS ENGINE REQUIRES ANOTHER SPECIAL GASKET AND PLATE TO BE INSTALLED WITH THE MS9144-01 GASKET TO PREVENT OIL LEAKAGE. THE OVERHAUL SHOP WAS UNAWARE OF THE SPECIAL GASKET STACK REQUIREMENT AND DELIVERED THE ENGINE TO THE MAINTENANCE SHOP WITHOUT GASKETS ON THE GOVERNOR PAD. THE MAINTENANCE SHOP USED ONLY THE MOONEY MAINTENANCE MANUAL, WHICH DOES NOT MENTION SPECIAL GASKETS, FOR THE ENGINE INSTALLATION AND INSTALLED THE PROP GOVERNOR WITH ONLY THE MS9144 GASKET.
Probable cause
the failure of the engine overhaul shop to install the correct gasket stack on the propeller governor pad as required by the engine manufacturer.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX95LA125
- Event ID
- 20001207X03140
- Case number
- LAX95LA125
- 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. 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: 26c81ddf0f3efca1baaff3a3466e5c8d8b3b7c4337d9c5eb95e6985e25b1f26c; retrieved 2026-09-21T22:22:26.588Z.