# NTSB ANC88LA138: de Havilland DHC-2, N98JH, Mcgrath, AK, September 16, 1988

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 15, 1988, 17:09 local (Sep 16, 1988, 01:09 UTC)
- Place: Mcgrath, AK
- Coordinates: 63.609657, -154.779266 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=63.6097&lon=-154.7793&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report November 7, 1989
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5079
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC88LA138
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5079/pdf
- Page: https://openairdocs.org/ntsb/ANC88LA138

## 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
  - engine assembly,valve,exhaust - failure,total (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - tundra (contributing factor)

## Analysis

WHILE CRUISING, THE PILOT-IN-COMMAND EXPERIENCED A ROUGH ENGINE AND FINALLY AN UNEXPLAINED POWER REDUCTION TO IDLE. HE WAS UNABLE TO GLIDE THE FLOAT EQUIPPED AIRPLANE TO A BODY OF WATER AND EXECUTED A FORCED LANDING ON THE TUNDRA WHERE THE AIRPLANE SUSTAINED SUBSTANTIAL DAMAGE. EXAMINATION OF THE ENGINE REVEALED A FAILED EXHAUST VALVE.

## Aircraft

- Registration: [N98JH](https://openairdocs.org/aircraft/N98JH), registered now, S/N 953 (OpenAirDocs)
- Reported make and model: de Havilland DHC-2
- Registry model: [Dehavilland-Air SVC Caravan DHC-2](https://openairdocs.org/model/dehavilland-air-svc-caravan-dhc-2) (registry code 2801830) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 953
- Airframe hours: 6800
- Engines: P&W R-985 450 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Willow Air Service
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, September 13, 1988
- Departed: INOKO RIVER, AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; airline transport; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 5,500 total, 1,300 in this make and model, 5,200 as pilot in command, 275 in the last 90 days, 120 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 50 statute miles
- Lowest ceiling: 5,000 ft broken
- Temperature: 50 °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 19880915039059A](https://openairdocs.org/incident/19880915039059A), Sep 15, 1988: Dhav DHC2*, Mcgrath, AK, Substantial damage. Engine went to idle en route. Landed float equipped aircraft on the tundra. An exhaust valve had failed.

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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