Aerospatiale SA315B accident near Thayne, Wyoming, April 15, 1982
On April 15, 1982 at about 4:53 pm local time, a Aerospatiale SA315B (helicopter), registered N48089, was substantially damaged in an accident near Thayne, Wyoming. It was a flight of an unrecorded kind under external-load helicopter rules (Part 133). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 15, 1982 · about 4:53 pm local time
- Place
- Thayne, Wyoming · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale SA315B · all SA315Bs on the register
- Registration
- N48089 · no longer on the register · serial 2397
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
THE HELICOPTER WAS HOVERING TO PICK UP A SLING LOAD WHEN A LOUD BANG WAS HEARD AND THE AIRCRAFT BEGAN TO SPIN COUNTER CLOCKWISE. INVESTIGATION REVEALED THAT THE TAIL ROTOR DRIVE SHAFT HAD BROKEN. "EXAMINATION OF THE SHAFT BREAK DISCLOSED A SMALL FRACTURE REGION TYPICAL OF FATIGUE CRACKING."
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: commercial pilot
- Ratings: multi-engine land; single-engine land; rotorcraft: helicopter
- Flight time: 3,270 hours in all; 500 in this make and model; 50 in the last 90 days; 5 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: unk
The aircraft
- Airframe total time: 3,149 hours
- Last inspection: inspection type not recorded; 114 hours since
- Maximum gross weight: 4,300 lb
- Seats: 5
- Landing gear: fixed
- Engine: Turbo Meca ARTOUSTE IIIB (turboshaft); 0 hours total
- Operator: Evergreen Helicopters, INC.
The flight
- Departed from: Afton WY
- Destination: Afton WY
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 270° at 10 knots
- Visibility: 10 statute miles
- Sky: not recorded; not recorded
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 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.