# Accident 19960713016949A: Skrsky CH54A, Ketchikan, AK, July 13, 1996

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: July 13, 1996, 13:25 local time
- Place: Ketchikan, AK
- Damage: Destroyed
- Phase of flight: Hovering
- Operating rules: Rotorcraft external load (Part 133)
- Location: 55.6106° N, 131.5796° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=55.6106&lon=-131.5796&mi=10
- Aircraft: N541SB, a cancelled registration (https://openairdocs.org/deregistered/N541SB-1997-03-24) (OpenAirDocs)
- Registry model: Silver Bay Logging CH-54A (registry code 8160000, https://openairdocs.org/model/silver-bay-logging-ch-54a) (OpenAirDocs)
- Reported make and model: SKRSKY CH54A
- Reported engine: PWA JFTD12A4A
- People aboard: 1
- Fatal injuries: 1
- Pilot flight hours: 7,985 total, 500 in this make and model, 125 in the last 90 days
- NTSB investigation: [NTSB ANC96FA098](https://openairdocs.org/ntsb/ANC96FA098) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19960713016949A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

ON LOGGING EXPEDITION WHEN ROTOR BLADE STRCUK TREES. (.4)THE PILOT & COPILOT WERE ON AN EXTERNAL LOAD, AERO LOGGING OPERATION IN A MILITARY SURPLUS HELICOPTER, LIFTING AN ESTIMATED LOAD OF 18,000 LBS. GROUND PERSONNEL HEARD A POPPING SOUND, THEN SAW THE TAILROTOR BEGIN TO SLOW DOWN AS THE HELICOPTER BEGAN TO YAW/SPIN. IT DESCENDED TO SLOPING TERRAIN IN AN AREA OF CUT LOGS. POSTCRASH EXAM OF THE TAILROTOR DRIVE SHAFT REVEALED A SEPARATION AT THE NUMBER 5 BEARING POSITION. THE SHAFT SEPARATION EXHIBITED EVIDENCE OF HIGH HEAT & MELTING OF ADJOINING SHAFT SURFACES. THE BEARING & ITS HOUSING WERE NOT RECOVERED. THE BEARING HAD ACCRUED 505 HRS OF SERVICE, & WAS 1 OF 2 BEARING MODEL NUMBERS THAT WERE IN USE. THE BEARING WAS MANUFACTURED IN 1991, & WAS PURCHASED BY THE OPERATOR FROM SURPLUS MILITARY SUPPLIES. THE SUPPLIER (OF THE BEARING TO THE OPERATOR) HAD PERFORMED AN EXTERIOR EXAM OF THE BEARING & MARKED 'RELUBED 10/95' ON THE BEARING BOX. EXAM OF THE REMAINING TAILROTOR DRIVE SHAFT BEARINGS REVEALED EVIDENCE OF LOW GREASE FILL, WATER & GLYCOL CONTAMINATION, & WEAR PATTERNS CONSISTENT WITH MISALIGNMENT. IN CIVILIAN SERVICE, THE BEARING WAS AN 'ON CONDITION' PART.                       THE OPERATOR ESTABLISHED A SERVICE LIFE OF 1,000 HOURS FOR AERO LOGGING OPERATIONS. A SHELF LIFE FOR THE BEARING WAS NOT ESTABLISHED.  THE MANUFACTURER INDICATED THE BEARING SHOULD SUPPORT A 5 YEAR SHELF LIFE.  OTHER OPERATORS OF THE ACCIDENT HELICOPTER IN AERO LOGGING REPORTED SIMILAR EXAMPLES OF LOW GREASE FILL & BEARING CONTAMINATION FROM WATER IN BOTH AVAILABLE MODELS OF BEARING.

## The NTSB's investigation of this event (1)

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 ANC96FA098](https://openairdocs.org/ntsb/ANC96FA098), Jul 13, 1996: Sikorsky CH-54A (N541SB), Ketchikan, AK, destroyed, 1 fatal. Probable cause: failure of the number 5 tailrotor bearing. A factor relating to the accident was: the uneven/steep sloping terrain, where the pilot was forced to land. Possible factors were: inadequate…

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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