Grumman G-164A accident near Patoka, Illinois, July 22, 2023
On July 22, 2023 at about 4:13 pm local time, a 1974 Grumman G-164A, registered N9892, was substantially damaged in an accident during maneuvering (low-alt flying) near Patoka, Illinois. 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 partial loss of engine power due to the failure of two compressor turbine blades as a result of the engine operating near or above the engine’s operating limits for an undetermined amount of time beyond the recommended engine’s TBO limit, which led to material creep and overload failure.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 22, 2023 · about 4:13 pm local time · cases in 2023
- Place
- Patoka, Illinois · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Grumman G-164A, built 1974 · all G-164As on the register
- Registration
- N9892 · registry record · serial 1324
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
While conducting an aerial application flight, the pilot observed a loss of engine power. Because the airplane was at a low altitude and its airspeed was decreasing, the pilot performed a forced landing in a corn field, which resulted in the airplane sustaining substantial damage to both wings, the fuselage, and empennage. An examination of the airplane’s turboprop engine showed rotational scoring, hard body impact damage, and missing material throughout the compressor turbine (CT) and power turbine (PT) sections of the engine, indicating that the engine was producing some level of power at the time of impact. Multiple CT blades were fractured above the blade platform and about 75% of the PT blades were fractured at various lengths above the blade platform. Metallurgical examination of two of the fractured CT blades showed material necking near the fracture surfaces, microstructural rafting, creep voids, and localized alteration of the microstructure that is consistent with heat-related material degradation. Examination of the fuel control unit showed the maximum Ng speed adjustment screw was adjusted to the maximum fuel flow position and lock-wired in place. Based on the condition of the blades, the loss of engine power was likely due to the failure of two CT blades as a result of the engine being operated near or above the engine’s operating limits for an undetermined amount of time beyond the recommended engine’s time between overhaul (TBO) limit; this led to material creep and the overload failure of the CT blades.
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 (partial) during maneuvering (low-alt flying) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Failure other cases naming the engine
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › (general) › Incorrect use/operation other cases naming the engine
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 16,442 hours in all; 16,261 in this make and model; 1,591 as pilot in command
- Last flight review: March 13, 2023
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: ctr
- Injury: no injuries
The aircraft
- Airframe total time: 14,217 hours
- Last inspection: annual inspection, May 9, 2023
- Maximum gross weight: 6,369 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt and Whitney Canada PT6-20A (turboprop); 14,092 hours total
- Operator: Redditt Air Service INC
The flight
- Departed from: SLO Salem IL at 3:50 pm
- Destination: SLO Salem IL
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 360° at 3 knots
- Visibility: 10 statute miles
- Sky: scat at 8,000 ft
- Temperature: 79°F (26°C), dew point 64°F (18°C)
- Altimeter: 29.97 inHg
- Observation at 11:15 am from KAJG, 14 miles away
Weather report (METAR): KAJG 221615Z AUTO 36003KT 10SM SCT080 26/18 A2997 RMK AO2 T02640181
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Photographs from the investigation 3 pictures from the NTSB's docket, as the NTSB released them
Photograph 1 – Airplane Front View
Photograph 2 – Airplane Rear View
Photograph 3 – Airplane Left Side ViewThe NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on July 8, 2025. 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 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 7 pages | View Download |
| 2 | Photos of Airplane | PDF, 4 pages · our copy | View Download |
| 3 | N9892 Engine Logbook | PDF, 3 pages | View Download |
| 4 | CEN23LA317_POWERPLANT Factual_final | PDF, 46 pages | View Download |
| 5 | Release of Aircraft Wreckage, NTSB Form, Airframe | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N9892 the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- N9892 on the register today · the tail number may have moved to another aircraft since
- Grumman G-164 119 registered today · the model family and its accident history
- Grumman 443 aircraft on the register
- Engine: Pratt and Whitney Canada PT6-20A 16 aircraft carry this series today · as the NTSB recorded it
- Salem-Leckrone Airport · departed from
- Accidents and incidents in Illinois 2,118 since 1982 · 251 in the last ten years
- Illinois 8,070 aircraft registered
- Other NTSB records under N9892 1 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/CEN23LA317.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.