Amateur-built Cozy Mark IV accident near Sioux City, Iowa, May 30, 2011
On May 30, 2011 at about 1:00 pm local time, a amateur-built Cozy Mark IV, registered N204TJ, was substantially damaged in an accident during maneuvering near Sioux City, Iowa (Sioux Gateway Airport/Col. Bud). It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's improper installation of the gascolator gasket during the airplane's last condition inspection, which resulted in a partial loss of engine power while maneuvering.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 30, 2011 · about 1:00 pm local time
- Place
- Sioux City, Iowa · Sioux Gateway Airport/Col. Bud · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Cozy Mark IV
- Registration
- N204TJ · registry record · serial 204
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The airplane sustained a partial loss of engine power while maneuvering at 7,500 feet mean sea level about 10 miles from the departure airport. The pilot then elected to return to the departure airport for a precautionary landing. While en route, he smelled fuel and shut the fuel selector off. He executed a landing to a field after he realized that the glidepath would not reach the runway. The pilot stated that he did not install the gascolator gasket properly during his last condition inspection of the airplane, which resulted in air entering the fuel system and a subsequent partial loss of engine power.
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 maneuvering defining event
- Loss of engine power (partial) during maneuvering
- Engine shutdown during enroute (cruise)
- Loss of engine power (total) during enroute (descent)
- Collision with terrain or object (not controlled flight into terrain) during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft systems › Fuel system › Fuel filter › strainer › Incorrect service/maintenance
- cause Personnel issues › Task performance › Maintenance › Scheduled/routine maintenance › Pilot
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Pilot
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 2,021 hours in all; 1,763 in this make and model; 10 in the last 90 days; 5 in the last 30 days; 1,950 as pilot in command; 0 on instruments
- Last flight review: May 1, 2010
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 1,763 hours
- Last inspection: condition inspection, May 3, 2011
- Maximum gross weight: 2,250 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO360C1 (piston); 0 hours total
The flight
- Departed from: SUX Sioux City IA at 12:30 pm
- Destination: SUX Sioux City IA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 150° at 10 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 72°F (22°C), dew point 0°F (-18°C)
- Altimeter: 29.54 inHg
- Observation at 12:30 pm from SUX
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.