LAX91LA035 · Cessna 210M
Self Enterprises Cessna 210M · Accident: total loss of engine power (mechanical failure) en route
From an unrecorded airport to UNKNOWN
Event
- NTSB case
- LAX91LA035
- 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
Cessna 210M
- Aircraft type
- Cessna 210
- 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
- N9139M
- Operator
- Self Enterprises
- Onboard fatalities
- Unknown
- Route
- From not recordedTo UNKNOWN
- 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)
- 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, connecting rod › Bent
- Engine assembly, connecting rod › Fractured
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
A CESSNA 210M LOST ENG POWER AND COLLIDED WITH A POLE AFTER A FORCED LANDING ON A CITY STREET. THE ENGINE CRANKCASE WAS FRACTURED AND THE #5 PISTON CONNECTING ROD HAD SEPARATED FROM THE ENG AND WAS FOUND ALONG THE WRECKAGE PATH. EXAM OF THE NUMBER 5 CYLINDER WALL DISCLOSED EVIDENCE OF THE AREA BELOW THE NORMAL PISTON STROKE BEING SCRAPED BY THE PISTON RINGS. ACCORDING TO THE METALLURGIC REPORT, THE PISTON'S CONNECTING ROD FAILED DUE TO A FATIGUE CRACK. THE CONNECTING ROD WAS BENT SOME TIME AFTER INITIAL ENG OPERATION. THE BENDING THAT OCCURRED TO THE NO. 5 CONNECTING ROD IS CHARACTERISTIC OF AN HYD LOCK CONDITION WHERE THE PISTON IS FORCED AGAINST INCOMPRESSIBLE FLUIDS BETWEEN THE PISTON AND CYLINDER HEAD. NO INDICATION OF METALLURGICAL DEFECT WAS OBSERVED IN THE CONNECTING ROD. HARDNESS READINGS ON THE CONNECTING ROD, WHICH INDICATES THE STRENGTH, CONFORMED TO MATERIAL SPECIFICATIONS. THE MAINTENANCE RECORDS NOTE THAT A MAJOR OVERHAUL WAS ACCOMPLISHED 207.8 HOURS BEFORE THE ACCIDENT.
Probable cause
THE FAILURE OF THE NUMBER 5 CYLINDER PISTON CONNECTING ROD DUE TO BENDING AND SUBSEQUENT FATIGUE FRACTURE. CONTRIBUTING TO THE ACCIDENT WAS THE IMPROPER STARTING PROCEDURE ACCOMPLISHED BY AN UNIDENTIFIED PERSON WHICH RESULTED IN EXCESSIVE FUEL IN THE CYLINDER RESULTING IN A HYDRAULIC LOCK WITHIN THE NUMBER 5 CYLINDER.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX91LA035
- Event ID
- 20001212X24640
- Case number
- LAX91LA035
- 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: 491e90d53f3ae57deafec243d005783d75ab524a57ccf3d34295f9e97b636f75; retrieved 2026-09-21T15:33:21.841Z.