Wsk Pzl Mielec M-18A accident near Anderson, Indiana, July 25, 2011
On July 25, 2011 at about 6:17 pm local time, a Wsk Pzl Mielec M-18A, registered N92640, was substantially damaged in an accident during maneuvering (low-alt flying) near Anderson, Indiana. 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).
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The NTSB's probable cause their words, unchanged
The fatigue failure of the propeller governor speeder spring, which resulted in the pilot’s inability to control engine output power.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 25, 2011 · about 6:17 pm local time
- Place
- Anderson, Indiana · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Wsk Pzl Mielec M-18A
- Registration
- N92640 · no longer on the register · serial 1Z025-22
- 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 was marking a field in preparation for an aerial application when he experienced what he thought was an engine failure. He stated that the engine was still running, but it was not producing power. The pilot pushed the power lever forward; the engine power did not increase, but the engine temperature increased. He stated that the engine was idling fast and that he forced the airplane into a bean field about 150 to 200 yards ahead of a tree line. The pilot ground looped the airplane before contacting the trees. A postaccident examination of the engine did not reveal any anomalies. A bench test of the propeller governor revealed that the maximum speed was above the nominal limit and the minimum speed was below the nominal limit. The control lever position was set higher than the specified position, which indicated that the governor had been adjusted in an attempt to regulate the propeller speed. X-rays and a teardown revealed that the propeller governor speeder spring was fractured. A metallurgical examination revealed a preexisting fatigue crack that, over time, resulted in the failure of the spring. The failed speeder spring would have resulted in a loss of oil pressure to the propeller piston, which allowed the propeller blades to rotate to a high blade angle, which then decreased the engine speed and overall power output of the engine. Maintenance records showed the propeller governor was overhauled on May 19, 2009. The speeder springs did not have serial numbers, and, therefore, the maintenance history of the speeder spring could not be determined.
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
- Collision with terrain or object (not controlled flight into terrain) during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Propeller system › Propeller governor › Failure
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 21,000 hours in all; 800 in this make and model
- Last flight review: February 27, 2010
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: ctr
- Injury: no injuries
The aircraft
- Airframe total time: 2,934 hours
- Last inspection: annual inspection, June 15, 2011
- Maximum gross weight: 11,000 lb
- Seats: 1
- Landing gear: fixed
- Engine: Honeywell TPE331-11U-61 (turboprop); 0 hours total
- Operator: Forest Air Services INC
The flight
- Departed from: Marion IN at 1:35 pm
- Destination: Marion IN
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 360° at 5 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 2,300 ft
- Temperature: 82°F (28°C), dew point 72°F (22°C)
- Altimeter: 29.95 inHg
- Observation at 5:53 pm from MIE, 12 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.
Other NTSB records under N92640 the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number CEN11LA512.