Bell 47G-3B-1 accident near Rock Springs, Wyoming, September 13, 2005
On September 13, 2005 at about 5:50 pm local time, a Bell 47G-3B-1 (helicopter), registered N24SD, was substantially damaged in an accident near Rock Springs, Wyoming (Na airport). It was an other work-use flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
the pilot's failure to maintain control of the helicopter during the attempted autorotation after he experienced an engine overspeed that occurred for reasons undetermined.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 13, 2005 · about 5:50 pm local time
- Place
- Rock Springs, Wyoming · Na · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-3B-1 · all 47G-3B-1s on the register
- Registration
- N24SD · registry record · serial 3671
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
According to the pilot, he was maneuvering at approximately 25 feet agl. The pilot stated that he heard a grinding noise and the "helicopter yawed to the right a couple of times." He stated that the engine began to overspeed and he initiated an autorotation. The pilot stated that the helicopter impacted the ground hard, resulting in substantial damage. An examination, revealed that all six shearbolts had failed. Examination of the fracture faces of the six shear bolts revealed signatures consistent with a shearing action. The examination of the helicopter airframe, engine, transmission, and remaining systems revealed no anomalies.
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: rotorcraft: helicopter
- Flight time: 2,940 hours in all; 1,540 in this make and model; 309 in the last 90 days; 116 in the last 30 days; 2,900 as pilot in command
- Last flight review: June 1, 2005
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 8,856 hours
- Last inspection: 100-hour inspection, August 1, 2005; 1,224 hours since
- Maximum gross weight: 2,950 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming TVO-435-B1A (piston); 0 hours total
The flight
- Departed from: RKS Rock Springs WY at 4:50 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: at 3 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 52°F (11°C), dew point 21°F (-6°C)
- Altimeter: 30.17 inHg
- Observation at 5:54 pm from RKS, 30 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.
Other NTSB records under N24SD the same tail number, which may have belonged to a different aircraft at the time
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.