Socata TB-20 Trinidad accident near Cassville, Wisconsin, September 3, 2008
On September 3, 2008 at about 8:53 pm local time, a Socata TB-20 Trinidad, registered N597TB, was substantially damaged in an accident during approach (VFR go-around) near Cassville, Wisconsin (Cassville Municipal Airport). It was a personal flight under general aviation rules (Part 91). 1 person was killed and 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The left seat pilot's failure to maintain control of the airplane during a go-around and the inadvertent in-flight opening of the cabin door for undetermined reasons. Contributing to the accident was the distraction of the door opening.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 3, 2008 · about 8:53 pm local time · cases in 2008
- Place
- Cassville, Wisconsin · Cassville Municipal Airport · cases near this airport · map
- Type
- Accident
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Socata TB-20 Trinidad · all TB-20 Trinidads on the register
- Registration
- N597TB · no longer on the register · serial 1817
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Two pilots, who were enrolled in an aviation training program, preflighted the airplane for a flight that was to pick up a friend at the destination airport. After departure, the right cabin door opened for reportedly unknown reasons, and was then held closed by the right seat pilot. The left seat pilot diverted to a nearby airport. During the approach the left seat pilot elected to perform a go-around because the approach "didn't look good." During the go-around, the door reopened, and the airplane rolled to the right and impacted the ground. The right seat pilot was fatally injuried. The airplane was equipped with gull wing type doors, which do not open against the direction of the relative airflow. The in-flight opening of a cabin door is not listed as an emergency in the Pilot's Information Manual and flight with a door open was not tested by the airplane manufacturer. Furthermore, flight is prohibited with a door being open or ajar. The airplane was consumed by fire and only portions of the door assemblies were recovered.
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
- Sys/Comp malf/fail (non-power) during unknown
- Loss of control in flight during approach (VFR go-around) defining event
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Aircraft › Aircraft structures › Doors › Passenger/crew doors › Not specified other cases naming the airframe structure
- factor Personnel issues › Psychological › Attention/monitoring › Task monitoring/vigilance › Pilot
- Organizational issues › Support/oversight/monitoring › Documentation/record keeping › Maintenance records › Operator
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › (general) › Not attained/maintained
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane
- Flight time: 329 hours in all; 53 in this make and model; 18 in the last 90 days; 4 in the last 30 days; 263 as pilot in command
- Last flight review: July 25, 2008
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: serious injuries
Crew member
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 181 hours in all; 2 in this make and model
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: rgt
- Injury: fatal
The aircraft
- Airframe total time: 3,912 hours
- Last inspection: 100-hour inspection, June 19, 2008
- Maximum gross weight: 3,086 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-540-C4D5D (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: DBQ Dubuque IA
- Destination: PDC Prairie du Chie WI
- Flight plan: none
- Runway 11, 3,000 ft by 50 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 350° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 73°F (23°C), dew point 55°F (13°C)
- Altimeter: 30.00 inHg
- Observation at 8:55 pm from PVB, 23 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
63 documents, released by the NTSB on August 18, 2009. 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.
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N597TB: not on the register today · the record of its deregistration
- Daher (Socata) TB-20 200 registered today · the model family and its accident history
- Engine: Lycoming IO-540-C4D5D 31 aircraft carry this series today · as the NTSB recorded it
- Cassville Municipal · nearest airport
- Dubuque Regional · departed from
- Prairie DU Chien Municipal · bound for
- Accidents and incidents in Wisconsin 1,622 since 1982 · 228 in the last ten years
- Wisconsin 6,164 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/CHI08LA272.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.