Sikorsky CH-54A accident near Ketchikan, Alaska, July 13, 1996
On July 13, 1996 at about 9:25 pm local time, a Sikorsky CH-54A (helicopter), registered N541SB, was destroyed in an accident near Ketchikan, Alaska. It was a flight of an unrecorded kind under external-load helicopter rules (Part 133). 1 person was killed and 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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 handling/labeling of the 'relubed' bearing by intermediate supplyier(s), and/or insufficient shelf life/service limits for military surplus parts.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 13, 1996 · about 9:25 pm local time
- Place
- Ketchikan, Alaska · map
- Type
- Accident
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky CH-54A
- Registration
- N541SB · no longer on the register · serial 68-18433
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
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 complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: flight instructor, commercial pilot, private
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 7,985 hours in all; 500 in this make and model; 125 in the last 90 days; 60 in the last 30 days; 6,190 as pilot in command; 700 on instruments
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 4,362 hours
- Last inspection: continuous airworthiness programme, July 10, 1996; 13 hours since
- Maximum gross weight: 42,000 lb
- Seats: 2
- Landing gear: fixed
- Engine: P&W JFTD12A-4A (turboshaft); 0 hours total
The flight
- Departed from: Shelter Cove AK at 4:08 pm
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 15 statute miles
- Sky: clear
- Temperature: 61°F (16°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.