# NTSB ANC89IA099: De Havilland DHC-3, N41755, Palmer, AK, June 20, 1989

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: June 20, 1989, 13:45 local (21:45 UTC)
- Place: Palmer, AK
- Coordinates: 61.620128, -148.979003 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=61.6201&lon=-148.9790&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report August 26, 1992
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5131
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC89IA099
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5131/pdf
- Page: https://openairdocs.org/ntsb/ANC89IA099

## Probable cause

INADEQUATE LUBRICATION WHICH RESULTED IN THE FAILURE OF THE HORIZONTAL STABILIZER'S TRIM ACTUATOR.

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach
  - flt control syst,stabilator trim - failure,total (cause)
  - maintenance,lubrication - inadequate, company maintenance personnel (cause)
  - maintenance,inspection - inadequate, company maintenance personnel (contributing factor)

## Analysis

THE AIRPLANE PITCHED ABRUPTLY NOSE DOWN FOLLOWING AN INFLIGHT FAILURE OF THE HORIZONTAL STABILIZER'S TRIM ACTUATOR JACK SCREW. THE CREW WAS ABLE TO MAINTAIN CONTROL OF THE AIRPLANE AND MAKE A SUCCESSFUL LANDING BY EXERTING A LARGE AMOUNT OF BACK PRESSURE ON THE CONTROL WHEEL AND ADDING NEARLY FULL ENGINE POWER. AN EXAMINATION OF THE ACTUATOR REVEALED AN INADEQUATE AMOUNT OF LUBRICATING GREASE AND EXCESSIVE PART WEAR.

## Aircraft

- Registration: [N41755](https://openairdocs.org/deregistered/N41755-2006-01-24), registration cancelled 2006-01-24, S/N 339, built 1959 (OpenAirDocs)
- Reported make and model: DE HAVILLAND DHC-3
- Registry model: [Dehavilland DHC-3](https://openairdocs.org/model/dehavilland-dhc-3) (registry code 2800202) (OpenAirDocs)
- Registry engine: [Pratt & Whitney W-S1H&S3H](https://openairdocs.org/engine/pratt-whitney-w-s1h-s3h) (registry code 52012, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 339
- Airframe hours: 9750
- Engines: P&W R-1340 600 horsepower reciprocating
- Damage: No damage
- Flight: Business, Part 91
- Operator: Woods Air Service
- Registered owner: Woods, Warren G
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, June 15, 1989
- Flight plan: Company VFR
- Airport: PAQ, Palmer

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: unknown, unknown; seat: left

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 100 statute miles
- Lowest ceiling: none
- Temperature: 64 °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).

- [Incident 19890620057679I](https://openairdocs.org/incident/19890620057679I), Jun 20, 1989: Dhav DHC3, Palmer, AK. Loud bang in tail area. Pitch down occured. Both pilots on yoke to land. Stabilizer actuator trim screw failed.

## Other investigations on N41755 (2)

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 ANC92LA109](https://openairdocs.org/ntsb/ANC92LA109), Jul 22, 1992: De Havilland DHC-3 (N41755), Mcgrath, AK, substantial damage. Probable cause: THE FIRE IN THE ENGINE ACCESSORY DRIVE ASSEMBLY. FACTOR WAS THE ROUGH AN UNEVEN FORCED LANDING AREA.
- [NTSB ANC82FA081](https://openairdocs.org/ntsb/ANC82FA081), Sep 1, 1982: de Havilland DHC-3 (N41755), Near Skwentna, AK, substantial damage

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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