Aerospatiale SA315B accident near Lyman, Wyoming, September 7, 1984
On September 7, 1984 at about 2:50 pm local time, a Aerospatiale SA315B (helicopter), registered N62338, was substantially damaged in an accident near Lyman, Wyoming. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). 5 people 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
- September 7, 1984 · about 2:50 pm local time
- Place
- Lyman, Wyoming · map
- Type
- Accident
- Injuries
- 5 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale SA315B · all SA315Bs on the register
- Registration
- N62338 · registry record · serial 2402
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
THE PLT STATED THAT ENGINE RPM BEGAN DETERIORATING DURING A CLIMB TO CRUISE FLT. HE RETURNED TO THE LANDING SITE WHERE THE RPM DECAYED TO FLT IDLE, AN AUTOROTATION WAS ENTERED AND A HARD LANDING RESULTED. THE ENGINE RAN FOR 1 HOUR IN A TEST CELL AFTER THE ACCIDENT AND NO EVIDENCE OF A MALFUNCTION WAS FOUND. THE FUEL SPEED GOVERNOR WAS REMOVED, TESTED AND FOUND TO FUNCTION NORMALLY HOWEVER DURING THE REMOVAL OF THE FUEL METERING SYSTEM PART OF AN 'O' RING WAS FOUND IN A SPRING NEXT TO THE FUEL PORTS. THE 'O' RING FRAGMENT COULD HAVE BLOCKED ONE OF THE FUEL PORTS ALLOWING THE RPM TO DROP TO FLIGHT IDLE.
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: single-engine land; rotorcraft: helicopter
- Flight time: 6,380 hours in all; 2,950 in this make and model; 50 in the last 90 days
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 3,547 hours
- Last inspection: approved inspection programme; 93 hours since
- Maximum gross weight: 4,300 lb
- Seats: 5
- Landing gear: fixed
- Engine: Turbomeca ARTOUSTE IIIB (turboshaft); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 090° at 10 knots
- Visibility: 10 statute miles
- Sky: overcast at 2,000 ft; not recorded at 2,000 ft
- Temperature: 46°F (8°C), dew point 34°F (1°C)
- Altimeter: 30.00 inHg
- Observation at 9:47 am from EVW
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 4 |
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.