ANC83FA131 · Cessna U206
Cessna U206 · Accident: partial loss of engine power (mechanical failure) during initial climb
From an unrecorded airport to LAKE CLARK, AK
Event
- NTSB case
- ANC83FA131
- 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
- Charter & commuter
- 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 U206
- 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
- N4661Z
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo LAKE CLARK, AK
- 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 135: Air Taxi & Commuter
- 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
- Initial climb
- 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, valve, intake › Foreign object damage
- Induction air control/system › Failure, partial
- Induction air control/system › Fatigue
- Induction air control/system › Inadequate
- Induction air control/system › Separation
- Manufacturer › Aircraft/equipment inadequate
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE ENG LOST POWER JUST AFTER A WATER TAKEOFF. THE ACFT LANDED STRAIGHT AHEAD IN MUSKEG & TUNDRA COLLAPSING THE FLOATS. ENG TEARDOWN REVEALED A METALLIC 'NUGGET' IN THE LEFT INTAKE MANIFOLD BETWEEN THE #4 & #6 PORTS. NUMEROUS MARKS WERE FOUND ON THE INSIDE OF BOTH INTAKE MANIFOLDS. THERE WAS MINOR DENTING, SCRATCHING & PEENING ON THE INTERIOR OF THE 90 DEG ELBOWS FROM BOTH ENDS OF THE CROSSOVER TUBE, INTAKE VALVE PORTS, SEATS & VALVE FACES OF CYLS 4,5 & 6. THE NUGGET WAS COMPOSED OF THE SAME MATERIAL AS THE AIRBOX ASS'Y, CESSNA P/N 1250705, WHICH CONTAINED TWO HOLES APRX 2-1/2 SQUARE INCHES EACH IN THE AIRBOX WALL. THE HOLES WERE CAUSED BY FATIGUE CRACKS. THE SOURCE OF LOADING CAUSING THE FATIGUE CRACKPROPAGATION WAS DUE TO MEMBRANE &/OR BENDING LOADS IN THE AIRBOX WALL CAUSED BY OUT-OF-PLANE DEFORMATION. THESE DEFORMATION WERE MOST LIKELY CAUSED BY EXCITING A NATURAL MODE OF VIBRATION IN THE WALL. THREE DUCT FAILURES WERE REPORTED TO THE FAA IN 1983, TWO OF WHICH WERE IN C-210 ACFT.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record ANC83FA131
- Event ID
- 20001214X43559
- Case number
- ANC83FA131
- 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 1983-07-25.
- API snapshot SHA-256: 0cb0772c97353ad4d82ee15b3e832c76b9bd88a7d831a42b5a77d42bff95d705; retrieved 2026-09-18T20:56:13.530Z.