LAX94FA165 · Ayres S-2R
Ayres S-2R · Accident: partial loss of engine power (mechanical failure) en route
From Truckee Tahoe Airport (TRK) to 4SD
Event
- NTSB case
- LAX94FA165
- 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
- 2 · all aircraft and ground
- Ground fatalities
- 1
- 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
Ayres S-2R
- Aircraft type
- Ayres S-2
- 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
- N40237
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Truckee Tahoe Airport (TRK), Truckee, CATo 4SD
- 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
- 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
- Engine assembly, bearing › Failure, partial
- Engine assembly, master rod › Failure, partial
- Lubricating system › Undetermined
- Operation with known deficiencies in equipment › Performed
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
ON THE PREVIOUS FLIGHT, THE PILOT MADE AN UNSCHEDULED STOP AT TRUCKEE DUE TO HIGH OIL TEMPERATURE & LOW OIL PRESSURE. AFTER CONSULTING WITH THE OWNER/OPERATOR, THE PILOT ARRANGED FOR A MECHANIC TO CHECK THE MAGNETIC DRAIN PLUG & ENGINE OIL SCREEN. THE MAGNETIC DRAIN PLUG WAS FREE OF PARTICLE DEBRIS & THE SCREEN HAD A FEW PARTICLES (NOT OUT OF ORDINARY). A DECISION WAS MADE TO FERRY THE PLANE TO RENO/STEAD, WHERE EXPERIENCED MAINTENANCE FOR WRIGHT ENGINES WAS AVAILABLE. DURING FLIGHT, THE PILOT REPORTED PROBLEMS WITH THE ENGINE & INDICATED HE WOULD LAND ON A ROAD. ONE WITNESS SAID HE SAW A PUFF OF WHITE SMOKE FOLLOWED BY BLACK SMOKE. WHILE LANDING, THE PLANE HIT ELECTRICAL LINES ALONG THE ROADWAY, THEN IT STRUCK A LIGHT POST, THE GROUND & A VAN. AN EXAM REVEALED METAL CHIPS ON THE OIL DRAIN PLUG & IN THE OIL SCREEN. TEAR- DOWN OF THE ENGINE REVEALED A WORN MASTER ROD JOURNAL WITH HEAT DISCOLORATION. TOXICOLOGY TESTS SHOWED 0.003 UG.ML OF TETRAHYDROCANNABINOL CARBOXYLIC ACID (MARIJUANA) IN THE PILOT'S BLOOD & 0.072 UG/ML IN HIS URINE.
Probable cause
AN UNDETERMINED PROBLEM WITH THE ENGINE OIL SYSTEM, A DECISION TO FLY THE AIRPLANE WITH A KNOWN DEFICIENCY, AND PROGRESSIVE (PARTIAL) FAILURE OF THE ENGINE MASTER ROD AND BEARING.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX94FA165
- Event ID
- 20001206X00918
- Case number
- LAX94FA165
- 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: d2f0d36f21fdc98851b8ae18529227f9794f3479450a64beda037afb7cea169c; retrieved 2026-09-21T00:13:17.341Z.