# NTSB ANC89LA007: Cessna 207, N9965M, Perde Bay, AK, October 10, 1988

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 10, 1988, 10:36 local (18:36 UTC)
- Place: Perde Bay, AK
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 5 uninjured
- Status: Completed, report September 11, 1989
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5138
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC89LA007
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5138/pdf
- Page: https://openairdocs.org/ntsb/ANC89LA007

## 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,piston - burned (cause)
  - fluid,oil - exhaustion (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - tundra (contributing factor)
  - terrain condition - rough/uneven (contributing factor)

## Analysis

THE PILOT EXPERIENCED A POWER LOSS DURING CRUISE FLIGHT AND DURING HIS DESCENT THE ENGINE STOPPED PRODUCING POWER. HE LANDED ON THE TUNDRA AND THE AIRPLANE WAS SUBSTANTIALLY DAMAGED. AN ENGINE TEARDOWN REVEALED THAT THE NUMBER 4 PISTON WAS BURNED PAST COMPRESSION RING, WHICH PRESSURIZED THE CASE AND FORCED THE OIL OUT. THE ENG THEN SEIZED.

## Aircraft

- Registration: [N9965M](https://openairdocs.org/deregistered/N9965M-2010-02-01), registration cancelled 2010-02-01, S/N 20700767, built 1983 (OpenAirDocs)
- Reported make and model: CESSNA 207
- Registry model: [Cessna 207A](https://openairdocs.org/model/cessna-207a) (registry code 2073605) (OpenAirDocs)
- Registry engine: [Continental IO-520-F](https://openairdocs.org/engine/continental-io-520-f) (registry code 17237, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 20700767
- Engines: CONTINENTAL IO-520 300 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 135
- Operator: Cape Smyth Air Services Inc.
- Registered owner: Audi Air
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, October 1, 1988, 18 hours before
- Departed: BRW, BARROW, AK
- Destination: PHO, POINT HOPE, AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 31; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 3,700 total, 1,200 in this make and model, 2,600 as pilot in command, 230 in the last 90 days, 80 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 300° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: 1,500 ft overcast
- Temperature: 5 °F

## 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 19881010045709A](https://openairdocs.org/incident/19881010045709A), Oct 10, 1988: Cessna 207A, Perde Bay, AK, Substantial damage. Lost oil pressure and engine seized. Crash landed on tundra. Hole burned in piston caused pressure to force oil out

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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