Amateur-built COZY MK-IV accident near Osceola, Missouri, November 5, 2008
On November 5, 2008 at about 3:45 pm local time, a amateur-built COZY MK-IV, registered N637PS, was substantially damaged in an accident during enroute (cruise) near Osceola, Missouri (Osceola Municipal Airport, Mo). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A total loss of engine power due to an obstruction of airflow as a result of the pilot's inadvertent actuation of the landing brake.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 5, 2008 · about 3:45 pm local time
- Place
- Osceola, Missouri · Osceola Municipal Airport, Mo · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built COZY MK-IV
- Registration
- N637PS · no longer on the register · serial 287
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private pilot was flying his homebuilt airplane on a cross-country flight at 5,500 feet mean sea level when he encountered some turbulence. The engine began to overheat and lose power and the pilot diverted to a nearby airport. The pilot could not make the runway and landed on a grassy, unimproved area on the airport. The airplane struck a pole, crossed a road, struck a second pole, and came to rest inverted. Both wings and a portion of the nose were separated from the airplane and the pilot was seriously injured. The pilot stated that he thought he had inadvertently actuated the landing brake in the turbulence, which blocked airflow to the engine and caused the engine to overheat and lose power. According to the builders manual, deployment of the landing brake can disrupt airflow to the engine and cause overheating. The airplane had been modified from the original design, replacing the mechanical landing brake system with an electrical one.
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
- Miscellaneous/other during prior to flight
- Loss of engine power (total) during enroute (cruise) defining event
- Off-field or emergency landing during enroute (cruise)
- Landing area overshoot during landing (landing roll)
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- cause Aircraft › Aircraft systems › (general) › (general) › Unintentional use/operation
- Aircraft › Aircraft power plant › Power plant › Air intake › Damaged/degraded
- Aircraft › Aircraft power plant › Power plant › (general) › Failure
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Pilot
- cause Personnel issues › Task performance › Use of equip/info › Use of equip/system › Pilot
- Environmental issues › Conditions/weather/phenomena › Turbulence › Clear air turbulence › Effect on operation
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 379 hours in all; 119 in this make and model; 30 in the last 90 days; 27 in the last 30 days; 328 as pilot in command
- Last flight review: April 3, 2008
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 119 hours
- Last inspection: condition inspection, April 3, 2008
- Maximum gross weight: 2,086 lb
- Seats: 4
- Landing gear: retractable
- Engine: Lycoming O&VO-360 SER (piston); 0 hours total
The flight
- Departed from: 3SQ St Charles Muni MO
- Destination: TDW Amarillo TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 190° at 18 knots, gusting 28
- Visibility: 10 statute miles
- Sky: a few clouds at 13,000 ft
- Temperature: 68°F (20°C), dew point 54°F (12°C)
- Altimeter: 29.78 inHg
- Observation at 3:55 pm from SZL, 50 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.