Thrush S2R-H80 incident near Donalsonville, Georgia, September 28, 2020
On September 28, 2020 at about 8:30 pm local time, a 2016 Thrush S2R-H80, registered N6216K, suffered minor damage in an incident during maneuvering (low-alt flying) near Donalsonville, Georgia. 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
A total loss of engine power due to a loose torque meter attachment nut in the reduction gearbox that jammed the planetary gearset causing the power turbine shaft to separate from the power turbine disk, resulting in the power turbine overspeeding and shedding blades that penetrated the compressor turbine case.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 28, 2020 · about 8:30 pm local time
- Place
- Donalsonville, Georgia · map
- Type
- Incident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Thrush S2R-H80, built 2016
- Registration
- N6216K · registry record · serial H80-182
- Damage
- Minor damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The incident engine suffered a release of low-energy power turbine blade debris due to a power turbine overspeed event. One or more hex nuts that secure the torque meter support within the reduction gearbox came loose and backed off from its threaded stud. A loose nut then became wedged between the mating teeth of the stage 2 planetary gears and crown wheel and the sudden torque shock caused teeth to fracture on one stage 1 planetary gear. Once these teeth fractured, mis-meshing between the stage 1 planetary gears and the sun gear occurred resulting in the 360° fracture and liberation of the sun gear teeth. The reduction gearbox then became decoupled from the power turbine, allowing for overspeed to occur
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
- Loss of engine power (total) during maneuvering (low-alt flying) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Failure
The aircraft
- Airframe total time: 2,758.5 hours
- Last inspection: annual inspection, January 5, 2020; 405.3 hours since
- Maximum gross weight: 10,500 lb
- Seats: 1
- Landing gear: fixed
- Engine: Ge Aviation H80-100 (turboshaft); 2,759 hours total
- Operator: Custom Ag And Air Inc.
The flight
- Departed from: 17J Donalsonville GA at 8:00 pm
Weather at the time
- Light: daylight
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on April 26, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Powerplant Group Chairman's Factual Report | PDF, 17 pages | View Download |
| 2 | Powerplants Metallurgical Report Attachment 1 | PDF, 60 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.