# NTSB ANC92FA002: Cessna 172M, N20024, Bethel, AK, October 3, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Field investigation · Final report
- Date: October 3, 1991, 14:35 local (22:35 UTC)
- Place: Bethel, AK
- Coordinates: 60.809013, -161.850097 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=60.8090&lon=-161.8501&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 5 uninjured
- Status: Completed, report March 31, 1993
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5636
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC92FA002
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5636/pdf
- Page: https://openairdocs.org/ntsb/ANC92FA002

## Probable cause

A POWER LOSS OVER UNSUITABLE TERRAIN WHICH RESULTED IN A NOSE OVER.

## 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
  - engine assembly,timing gear - worn (cause)
- Nose over, landing - roll
  - terrain condition - tundra (contributing factor)

## Analysis

DURING CRUISE FLIGHT THE PILOT HEARD A LOUD POP IN THE ENGINE COMPARTMENT AND THE ENGINE STOPPED PRODUCING POWER. DURING THE SUBSEQUENT FORCED LANDING ON THE TUNDRA, THE AIRPLANE NOSED OVER AND RECEIVED SUBSTANTIAL DAMAGE. EXAMINATION OF THE ENGINE REVEALED THAT THE CRANKSHAFT TIMING GEAR, PART NUMBER LW-15269, WAS EXTREMELY WORN AND ALL BUT NINE OF THE GEAR TEETH WERE MISSING.  ACCORDING TO TEXTRON LYCOMING, THE GEAR WAS THE ORIGINAL MANUFACTURED GEAR.

## Aircraft

- Registration: [N20024](https://openairdocs.org/deregistered/N20024-1998-06-02), registration cancelled 1998-06-02, S/N 17260940 (OpenAirDocs)
- Reported make and model: CESSNA 172M
- Registry model: [Cessna 172M](https://openairdocs.org/model/cessna-172m) (registry code 2072418) (OpenAirDocs)
- Category: Airplane
- Serial number: 17260940
- Airframe hours: 8251
- Engines: LYCOMING O-320-H2AD 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 135
- Operator: Village Aviation Corp, doing business as Camai Air
- Registered owner: Village Aviation Corp
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, September 25, 1991, 15 hours before
- Departed: BET, BETHEL, AK
- Destination: KKI, AKIACHAK, AK
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 26; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 2,475 total, 620 in this make and model, 2,324 as pilot in command, 304 in the last 90 days, 124 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 8 knots
- Visibility: 20 statute miles
- Lowest ceiling: 2,000 ft broken
- Temperature: 45 °F, dew point 43 °F
- Altimeter: 29.00 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 19911003044619A](https://openairdocs.org/incident/19911003044619A), Oct 3, 1991: Cessna 172M, Bethel, AK, Substantial damage. Loud pop. Engine quit. Nosed over landing on tundra. Crankshaft gear was stripped and torn out. 927HRS since tbo.

## Other investigations on N20024 (1)

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.

- [NTSB ANC97LA010](https://openairdocs.org/ntsb/ANC97LA010), Dec 4, 1996: Cessna 172M (N20024), Bethel, AK, substantial damage. Probable cause: the pilot's improper planning/decision, and resultant failure to obtain/maintain sufficient airspeed during takeoff. A factor related the accident was: taking off with a tailwind.

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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