Ayres S2R-G6 accident near Riverton, Wyoming, June 11, 2012
On June 11, 2012 at about 1:20 pm local time, a Ayres S2R-G6, registered N70WY, was substantially damaged in an accident during enroute near Riverton, Wyoming (Riverton Regional airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An engine overspeed shortly after takeoff for reasons that could not be determined because postaccident examination revealed no mechanical malfunctions or failures that would have precluded normal operation.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 11, 2012 · about 1:20 pm local time
- Place
- Riverton, Wyoming · Riverton Regional · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Ayres S2R-G6
- Registration
- N70WY · registry record · serial G6-127
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, shortly after departure, he observed the torque and temperature gauges move to extremely high values. The engine did not respond to speed or power lever inputs; however, the pilot reported that the linkage and amount of travel of the controls felt normal. The pilot diverted to a nearby airport and, when the airplane was lined up for landing on the runway, he shut down the engine. The pilot reported that, during the final descent, the airplane encountered a downdraft and collided with a light. Subsequently, the pilot was unable to maintain the airplane on an adequate descent glidepath, and it touched down in the dirt short of the runway. Postaccident examination of the engine revealed no mechanical anomalies that would have precluded normal operation. Examination of the fuel control unit revealed several anomalies within the unit; however, none of those anomalies would have resulted in the reported engine overspeed condition.
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
What happened, in order
- Powerplant sys/comp malf/fail during enroute defining event
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during approach (VFR pattern final)
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Descent/approach/glide path › Attain/maintain not possible
- Environmental issues › Conditions/weather/phenomena › Wind › Downdraft › Ability to respond/compensate
- Environmental issues › Physical environment › Object/animal/substance › Pole › Effect on equipment
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 14,500 hours in all; 350 in this make and model; 50 in the last 90 days
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Landing gear: fixed
- Engine: Honeywell (turboprop); 0 hours total
- Operator: Sky Aviation
The flight
- Departed from: Riverton WY at 1:15 pm
- Destination: RIW Riverton WY
- Flight plan: not recorded
- Runway 28, 8,203 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 270° at 12 knots, gusting 21
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 48°F (9°C), dew point 28°F (-2°C)
- Altimeter: 30.21 inHg
- Observation at 1:53 pm from KRIW
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.