# NTSB ANC89FA041: Cessna U206G, N756EA, Fairbanks, AK, February 9, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: February 9, 1989, 09:05 local (13:05 UTC)
- Place: Fairbanks, AK
- Location: 64.8378° N, 147.7164° W: Placed by OpenAirDocs: center of Fairbanks, AK, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=64.8378&lon=-147.7164&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report January 22, 1991
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5099
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC89FA041
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5099/pdf
- Page: https://openairdocs.org/ntsb/ANC89FA041

## Probable cause

SEPARATION OF THE TORSIONAL VIBRATION DAMPERS FROM THE CRANKSHAFT BOSS.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power(total) - mech failure/malf, cruise - normal
  - eng assembly,crankshaft counterweights/vib damper - separation (cause)
- Forced landing, descent - emergency
- In flight collision with object, landing - flare/touchdown
  - object - tree(s) (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

DURING FLIGHT, THE PILOT REPORTED AN ENGINE FAILURE. SUBSEQUENTLY, THE AIRPLANE CRASHED AS IT WAS LANDED IN A STAND OF PINE TREES. AN EXAM OF THE ENGINE REVEALED THAT ONE OF THE REAR TORSION VIBRATION DAMPERS HAD SEPARATED FROM THE CRANKSHAFT BOSS. THERE WAS EVIDENCE THAT THIS RESULTED IN MASSIVE INTERNAL ENGINE DAMAGE & A SUBSEQUENT LOSS OF POWER.

## Aircraft

- Registration: [N756EA](https://openairdocs.org/deregistered/N756EA-2013-09-20), registration cancelled 2013-09-20, S/N U20604021, built 1977 (OpenAirDocs)
- Reported make and model: CESSNA U206G
- Registry model: [Cessna U206G](https://openairdocs.org/model/cessna-u206g) (registry code 2073356) (OpenAirDocs)
- Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: U206044021
- Airframe hours: 3830
- Engines: CONTINENTAL IO-520-F 300 horsepower reciprocating
- Damage: Destroyed
- Flight: Part 135
- Operator: Arctic Circle Air Service Inc
- Registered owner: Constance & Ralph C. Seekins
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, November 1, 1988, 230 hours before
- Departed: FAI, FAIRBANKS, AK
- Destination: FYU, FORT YUKON, AK
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 2,500 total, 600 in this make and model, 2,150 as pilot in command, 193 in the last 90 days, 45 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 5 knots
- Visibility: 90 statute miles
- Lowest ceiling: 6,000 ft broken
- Temperature: 30 °F
- Altimeter: 30.00 inHg

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19890209001979A](https://openairdocs.org/incident/19890209001979A), Feb 9, 1989: Cessna U206G, Fairbanks, AK, Destroyed, 1 fatal. Engine failed en route, struck trees, stalled,impacted vertically. Counter weights and bushing failed on crankshaft

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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