LAX04LA251 · SOCATA TB-20
SOCATA TB-20 · Accident: total loss of engine power (mechanical failure) en route
From French Valley Airport (F70) to Reno Tahoe International Airport (RNO)
Event
- NTSB case
- LAX04LA251
- 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
SOCATA TB-20
- Aircraft type
- Socata TB-20
- 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
- N110U
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From French Valley Airport (F70), Murrieta, CATo Reno Tahoe International Airport (RNO), Reno, NV
- 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
- Fluid, oil › Exhaustion
- Lubricating system, oil gasket › Incorrect
- Pilot in command › Maintenance, installation, inadequate
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The airplane collided with ground obstructions during a forced landing following a catastrophic engine failure due to oil exhaustion during cruise flight. Just after achieving cruise altitude the pilot was scanning the cockpit gauges and he noticed the oil pressure gauge indicating a loss of pressure, with the oil warning light flickering intermittently. About 5 minutes later, the engine started to vibrate, and subsequently seized, making a loud bang. The airplane began to descend about 1,000 feet per minute, and the pilot selected a dirt field to perform an emergency landing. During the landing roll, the airplane impacted a berm. An engine examination revealed that the inside top of the engine cowling showed a concentration of oil near the firewall on the left side, which is the approximate location of the vacuum pump. Removal of the vacuum pump revealed an oily film on both sides of the pump gasket, which is seated between the vacuum pump flange and the engine accessory case flange. The vacuum pump had been installed about 0.5 hours prior to the accident. The mechanic who installed the pump said he used the gasket that was supplied with the pump. The manufacturer of the vacuum pump reported that they supply a gasket (part number AS3491-01) with their pump. In the TB-20 parts manual, the airplane manufacturer specifies that the gasket required is part number Z00.N7423254013, which they cross-reference with Textron Lycoming part number 8313. The investigation was unable to cross-reference or establish an equivalency between the AS3491-01 gasket supplied by the pump manufacturer with either the Lycoming or Socata specified gasket.
Probable cause
A loss of engine power due to oil exhaustion as a result of the mechanic's use of an incorrect gasket during the installation of the vacuum pump.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX04LA251
- Event ID
- 20040708X00929
- Case number
- LAX04LA251
- 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: 2efd2555927c8221a4633aae87fd13d94ead563e8787c077c58c1c4673cf69c7; retrieved 2026-09-22T07:13:37.662Z.