# NTSB ANC82IA048: De Havilland DHC-6-100, N525N, Near Port Heide, AK, June 16, 1982

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: June 16, 1982, 15:01 local (23:01 UTC)
- Place: Near Port Heide, AK
- Coordinates: 56.299156, -158.359939 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=56.2992&lon=-158.3599&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 10 uninjured
- Status: Completed, report June 16, 1983
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 71915
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC82IA048
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/71915/pdf
- Page: https://openairdocs.org/ntsb/ANC82IA048

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, cruise - normal
  - reduction gear assy,reduction gear - binding(mechanical) (cause)

## Analysis

WHILE IN CRUISE FLIGHT, THE LEFT ENGINE SURGED TWICE AND THE PILOT OBSERVED FIRE EMITTING FROM THE EXHAUST AND COWLING. AFTER SECURING THE ENGINE AND DISCHARGING THE FIRE BOTTLE WITHOUT EFFECT, THE PILOT MADE A PRECAUTIONARY LANDING AT PORT HEIDEN AIRPORT. INVESTIGATION REVEALED THAT THE ENGINE HAD EXPERIENCED A SEIZURE OF THE PLANETARY "X" GEAR. THE MODE OF FAILURE OF THE SUBJECT GEAR WAS NOT IDENTIFIED.

## Aircraft

- Registration: [N525N](https://openairdocs.org/deregistered/N525N-2013-05-30), registration cancelled 2013-05-30, S/N 92 (OpenAirDocs)
- Reported make and model: DE HAVILLAND DHC-6-100
- Registry model: [Dehavilland DHC-6 TWIN OTTER](https://openairdocs.org/model/dehavilland-dhc-6-twin-otter) (registry code 2802606) (OpenAirDocs)
- Category: Airplane
- Serial number: 92
- Airframe hours: 23287
- Engines: P & W PT6 A-20 550 horsepower turbo prop
- Damage: Minor damage
- Fire: In-Flight
- Flight: Part 135
- Operator: Sea Airmotive, Inc.
- Registered owner: Sea Airmotive, Inc.
- Departed: AKN, KING SALMON, AK
- Destination: Z79, CHIGNIK, AK
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; flight instructor, airline transport, commercial; airplane ratings: multi-engine land, single-engine land, multi-engine sea, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; flight hours: 9,050 total, 150 in the last 90 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 20 statute miles
- Lowest ceiling: 6,000 ft broken

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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