# NTSB ATL94LA025: Sikorsky H34-G, N8503J, Walterboro, SC, December 1, 1993

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: December 1, 1993, 15:25 local (20:25 UTC)
- Place: Walterboro, SC
- Coordinates: 32.899612, -80.669204 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.8996&lon=-80.6692&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report October 20, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 3330
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL94LA025
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3330/pdf
- Page: https://openairdocs.org/ntsb/ATL94LA025

## Probable cause

The seizure of the aircraft throttle to engine linkage for unknown reasons.

## 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, hover
  - throttle/power lever - seized (cause)
- Forced landing, descent - emergency
- In flight collision with object, descent - emergency
  - object - tree(s)
- In flight collision with terrain/water, descent - emergency

## Analysis

THE HELICOPTER WAS CONDUCTING LONG LINE EXTERNAL LOGGING OPERATIONS. THE PILOT STATED THAT HE WAS AT A HOVER, WITHOUT A LOAD, AND THE AIRCRAFT THROTTLE SEIZED AT ABOUT HALF THROTTLE. HE EXECUTED A FORCED LANDING INTO A GROUP OF TREES, AND THE AIRCRAFT RECEIVED SUBSTANTIAL DAMAGE. INSPECTION OF THE THROTTLE AND THROTTLE LINKAGE TO THE ENGINE DID NOT REVEAL ANY MALFUNCTION.

## Factual narrative

On December 1, 1993, at about 1525 eastern standard time, a Sikorsky H34-G, N8503J, was substantially damaged following a collision with terrain near Walterboro, South Carolina. The commercial pilot received minor injuries in the accident. The helicopter was being operated under 14 CFR Part 133 by Helicopter Lumberjacks of Paragold, Arkansas. Visual meteorological conditions existed at the time, and no flight plan had been filed for the local, logging operation.

The pilot stated that while at a hover during logging operations, the throttle stuck at a partial power setting, and he was forced to execute an emergency landing in the trees. The aircraft was substantially damaged during the emergency landing.

Inspection of the throttle linkage to the engine following the accident did not reveal any malfunction of the linkage or throttle.

## Aircraft

- Registration: [N8503J](https://openairdocs.org/deregistered/N8503J-1995-04-06), registration cancelled 1995-04-06, S/N 138471 (OpenAirDocs)
- Reported make and model: SIKORSKY H34-G
- Registry model: [Sikorsky UH-34G](https://openairdocs.org/model/sikorsky-uh-34g) (registry code 8141817) (OpenAirDocs)
- Category: Helicopter
- Serial number: 138471
- Airframe hours: 6203
- Engines: Curtis Wright 989C9HE2 1525 lbs thrust reciprocating
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Operator: William L. Mitchell III, doing business as Helicopter Lumberjacks
- Registered owner: William L. Mitchell III
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, December 10, 1992, 319 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; commercial; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 7,800 total, 1,000 in this make and model, 7,500 as pilot in command, 40 in the last 90 days, 25 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 40° at 9 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 57 °F, dew point 39 °F
- Altimeter: 30.00 inHg
- Observed at: CHS, 45 nm away

## 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 19931201045769A](https://openairdocs.org/incident/19931201045769A), Dec 1, 1993: Skrsky S58, Walterboro, SC, Substantial damage. During hover logging report throttle stuck at partial power. Landed in trees. Throttle or linkage defect found.

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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