ANC92LA152 · Cessna 206
Cessna 206 · Accident: partial loss of engine power (mechanical failure) en route
From RED SHEEP CREEK, AK to an unrecorded destination
Event
- NTSB case
- ANC92LA152
- 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 206
- Aircraft type
- Cessna 206
- 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
- N8070Z
- Operator
- Larry R. Rivers · private individual
- Onboard fatalities
- Unknown
- Route
- From RED SHEEP CREEK, AKTo not recorded
- 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, cylinder › Fatigue
- Engine assembly, cylinder › Overtemperature
- Pilot in command › Aircraft weight and balance, exceeded
- Pilot in command › Powerplant controls, improper use of
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE PILOT LOADED THE 2 PASSENGERS AND GEAR IN THE AIRPLANE TO THE EXTENT THAT IT TOOK SUCCESSIVE ATTEMPTS TO CLOSE THE DOOR DUE TO THE GEAR WHICH 'FILLED UP THE AIRPLANE TO THE ROOF.' THE REAR PAX HAD TO LAY ON TOP OF MEAT AND CAMP SUPPLIES WITH 2 DOGS IN HIS LAP. THE AIRPLANE WAS ESTIMATED TO BE 772 LBS OVER MAX GROSS WEIGHT AT TAKEOFF. AFTER TAKEOFF THE AIRPLANE CLIMBED SLOWLY FOR APRX 55 MIN AT TAKEOFF POWER. A 'SLEDGEHAMMER' SOUND PRECEDED THE APPEARANCE OF OIL FLOWING INTO THE CABIN AREA. NO REDUCTION OF POWER WAS OBSERVED. THE OIL PRESSURE BEGAN DROPPING RAPIDLY, AND THE PILOT MADE A PRECAUTIONARY LANDING ON A BEACH. THE AIRPLANE NOSED OVER IN GRASS. ENGINE TEARDOWN EXAMINATION REVEALED THAT THE #6 CYLINDER HAD FAILED THROUGH THE HEAD-TO-BARREL THREADED JOINT. METALLURGICAL EXAMINATION REVEALED THAT THE FAILURE WAS THE RESULT OF FATIGUE CRACKING IN THE CYLINDER HEAD CASTING. THIS TYPE OF FAILURE OCCURS WHEN THE CYLINDER IS OPERATED AT ELEVATED TEMPERATURES (ABOVE MAXIMUM ALLOWABLE) FOR A CONSIDERABLE PERIOD OF TIME.
Probable cause
FATIGUE FAILURE OF AN ENGINE CYLINDER PRECIPITATED BY THE PILOT-IN-COMMAND INTENTIONALLY EXCEEDING THE ENGINE PERFORMANCE RATINGS IN ORDER TO SUSTAIN FLIGHT IN THE GROSSLY OVERWEIGHT CONDITION. A FACTOR CONTRIBUTING TO THE ACCIDENT WAS THE HIGH GRASS. A FACTOR CONTRIBUTING TO THE SEVERITY OF THE PASSENGER'S INJURY WAS THE UNSECURED CARGO.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC92LA152
- Event ID
- 20001211X15556
- Case number
- ANC92LA152
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1992-09-02.
- API snapshot SHA-256: 08c7b7436dcfe5ab1714cdfc4205847c3ef7acfc7d7489ad0777125924085315; retrieved 2026-09-21T14:45:29.607Z.