Aerospatiale SA-315B accident near Big Sky, Montana, October 5, 1998
On October 5, 1998 at about 8:30 pm local time, a Aerospatiale SA-315B (helicopter), registered N5803J, was destroyed in an accident near Big Sky, Montana. It was an other work-use flight 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 failure of the ground handlers (chokers) to follow procedures, and separation of the tail rotor system. Contributing factors were incorrect long line hook (size), jamming of the hook release, trees and gusty wind conditions.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 5, 1998 · about 8:30 pm local time
- Place
- Big Sky, Montana · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale SA-315B · all SA-315Bs on the register
- Registration
- N5803J · no longer on the register · serial 2646
- Damage
- Destroyed
- Flight
- Other work-use flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
The helicopter was engaged in logging operations associated with the clearing of a recreational ski lodge construction site. This was the first time the operator had worked with this particular ground crew (chokers). The chokers were briefed by the pilot-in-command (PIC) and were supposed to hook up only two marked logs at a time (marked with orange fluorescent paint). However, they hooked up three logs together, one of which was still rooted. During the lifting operation, the PIC encountered resistance and attempted to electrically release the long line several times without success. The failure of the long line to release was due to jamming because of the use of an oversize clevis attaching the hook. When the long line finally released after the use of the manual system, the helicopter rotated along its longitudinal axis at such an angle that the tail rotor contacted trees and separated from the aircraft. It then descended out of control until impacting the ground. Winds at the site were strong and gusty.
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; instrument: airplane; rotorcraft: helicopter
- Flight time: 18,000 hours in all; 8,500 in this make and model; 200 in the last 90 days; 90 in the last 30 days; 18,000 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 4,724 hours
- Last inspection: annual inspection, October 2, 1998; 3 hours since
- Maximum gross weight: 4,300 lb
- Seats: 5
- Landing gear: fixed
- Engine: Turbomeca ARTOUSTE IIIB (turboshaft); 0 hours total
The flight
- Departed from: BZN Bozeman MT at 3:00 pm
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 240° at 15 knots, gusting 18
- Visibility: 10 statute miles
- Sky: broken clouds at 25,000 ft; scat at 5,000 ft
- Temperature: 52°F (11°C), dew point 23°F (-5°C)
- Altimeter: 30.00 inHg
- Observation at 8:56 pm from BZN, 32 miles away
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.