Ayres Corporation S2R G6 accident near Tivoli, Texas, May 20, 2015
On May 20, 2015 at about 7:40 pm local time, a 1996 Ayres Corporation S2R G6, registered N3300U, was substantially damaged in an accident during landing near Tivoli, Texas. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the fuel control unit due to the worn stub shaft spline, which resulted in an engine overspeed. Contributing to the accident was maintenance personnel's inadequate inspection of the fuel control unit.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 20, 2015 · about 7:40 pm local time
- Place
- Tivoli, Texas · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Ayres Corporation S2R G6, built 1996 · all S2R G6s on the register
- Registration
- N3300U · registry record · serial G6-139
- 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, during the accident flight, which was the twelfth aerial application flight of the day, the engine made an uncommanded power acceleration. The pilot retarded the throttle lever, but the engine did not respond. The pilot subsequently made a forced landing into a field, and the airplane nosed over and then came to rest inverted. A postaccident examination of the airplane revealed no anomalies with the engine rigging. Examination of the fuel control unit revealed that the stub shaft spline was worn beyond the allowable limits. Such wear can allow the fuel control underspeed governor to be driven at a lower speed than the engine speed, which can increase fuel flow and engine speed and is consistent with the uncommanded power acceleration that occurred during the accident flight. A review of the airplane's maintenance records revealed that, 2 months before the accident flight, the fuel control unit was inspected for wear and damage in accordance with an airworthiness directive (AD). It is unlikely that the wear observed during the postaccident examination could have occurred between the time of the AD inspection and the accident. It is likely that the AD was either not accomplished as noted in the maintenance records or that maintenance personnel inadequately conducted the inspection.
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
- Nose over/nose down during landing defining event
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine fuel and control › Fuel controlling system › Fatigue/wear/corrosion
- factor Aircraft › Aircraft power plant › Engine fuel and control › Fuel controlling system › Inadequate inspection
- factor Personnel issues › Task performance › Maintenance › Scheduled/routine maintenance › Maintenance personnel
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 300 in the last 90 days
- Last flight review: May 18, 2015
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: sngl
- Injury: minor injuries
The aircraft
- Last inspection: continuous airworthiness programme, March 16, 2015
- Seats: 1
- Landing gear: fixed
- Engine: Airesearch TPE 331-10 (turboprop); 5,234 hours total
- Operator: A T Ag Services, LLC
The flight
- Departed from: Tivoli TX
- Destination: Tivoli TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 160° at 9 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 5,000 ft; scat at 2,900 ft
- Temperature: 84°F (29°C), dew point 73°F (23°C)
- Altimeter: 29.95 inHg
- Observation at 7:55 pm from KPKV, 17 miles away
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.