# NTSB SEA90LA083: Sikorsky S-58D, N94495, Juneau, AK, May 21, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: May 21, 1990, 16:05 local (23:05 UTC)
- Place: Juneau, AK
- Location: 58.3019° N, 134.4197° W: Placed by OpenAirDocs: center of Juneau, AK, within about 29 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=58.3019&lon=-134.4197&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 1 uninjured
- Status: Completed, report October 2, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41197
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA90LA083
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41197/pdf
- Page: https://openairdocs.org/ntsb/SEA90LA083

## Probable cause

THE FAILURE OF THE NUMBER 3 SEGMENT OF THE TAIL ROTOR DRIVE SHAFT ASSEMBLY.

## Sequence of events

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

- Airframe/component/system failure/malfunction, hover
  - rotor drive system,tail rotor drive shaft coupling - failure,total (cause)
- Loss of control - in flight, hover
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT EXPERIENCED LOSS OF TAIL ROTOR CONTROL WHILE AT A HIGH HOVER WITH AN EXTERNAL LOAD OF LOGS. THE ACFT BEGAN SPINNING TO THE RIGHT AND IMPACTED THE GROUND WHILE IN A SPIN. EXAMINATION OF THE WRECKAGE REVEALED A FRACTURE OF THE NO. 3 SEGMENT OF THE TAIL ROTOR DRIVE SHAFT ASSY.

## Aircraft

- Registration: [N94495](https://openairdocs.org/deregistered/N94495-1995-04-12), registration cancelled 1995-04-12, S/N 58730 (OpenAirDocs)
- Reported make and model: SIKORSKY S-58D
- Registry model: [Sikorsky S-58H](https://openairdocs.org/model/sikorsky-s-58h) (registry code 8141839) (OpenAirDocs)
- Category: Helicopter
- Serial number: 58-730
- Airframe hours: 5605
- Engines: CURTIS WRIGHT R-1820 1525 horsepower reciprocating
- Damage: Destroyed
- Flight: Other work use, Part 133
- Operator: Alaska Skycranes
- Registered owner: Unknown
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, May 11, 1990, 22 hours before
- Airport: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 30; flight instructor, commercial; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, invalid medical for flight; seat: right; flight hours: 4,242 total, 184 in this make and model, 4,100 as pilot in command, 71 in the last 90 days, 22 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 250° at 15 knots
- Visibility: 30 statute miles
- Lowest ceiling: 4,000 ft broken
- Temperature: 59 °F, dew point 43 °F
- Altimeter: 29.00 inHg
- Observed at: JNU, 20 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 19900521016969A](https://openairdocs.org/incident/19900521016969A), May 21, 1990: Skrsky S58D, Juneau, AK, Destroyed. Lost tail rotor authority while hovering with load of logs. Spun to hard ground impact. NR3 tail rotor shaft broke.

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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