Amateur-built CHALLENGER II accident near Neshkoro, Wisconsin, June 30, 2011
On June 30, 2011, a amateur-built CHALLENGER II, registered N12911, was substantially damaged in an accident during initial climb near Neshkoro, Wisconsin. 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).
Preview. This page is not yet listed for search engines.
The NTSB's probable cause their words, unchanged
The total loss of engine power during the initial climb due to a cold seizure as a result of a broken fan V-belt. Contributing to the accident was the passenger's interference with the flight controls during the forced landing.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 30, 2011
- Place
- Neshkoro, Wisconsin · map
- Type
- Accident
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built CHALLENGER II
- Registration
- N12911 · registry record · serial CH2-1296-1544
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Prior to the local flight, the pilot, who was seated in the rear seat, completed a preflight check and engine run-up. During the initial climb, at 1,200 feet above ground level, the engine lost total power and the pilot initiated a forced landing to a private grass airstrip. While maneuvering the airplane for the forced landing, the pilot felt his left rudder pedal pressed to the floor. The pilot thought that the passenger may have been frightened and stepped on the rudder pedal. The pilot instructed to the passenger to release the rudder pedal as the airplane entered into a slip and was losing altitude; however, the passenger did not respond to the pilot. Due to the loss of altitude, the airplane was unable to reach the airstrip and impacted trees. A postaccident examination of the engine revealed that the cooling fan V-belt was broken and that the pistons exhibited scoring signatures consistent with a cold seizure. According to the manufacturer, the engine is susceptible to cold seizures when there is inadequate cooling of the cylinders, such as with a broken cooling fan V-belt. Review of the engine manufacturer’s installation and operations manual revealed warnings that "the engine by design is subject to sudden stoppage," and that it does not conform to aircraft standards.
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 initial climb defining event
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Malfunction
- factor Personnel issues › Psychological › Mental/emotional state › Anxiety/panic › Passenger
Pilot
- Certificate: private
- Ratings: single-engine land; single-engine sea
- Flight time: 3,000 hours in all; 2,000 in this make and model
- Last flight review: October 5, 2010
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: rear
- Injury: serious injuries
The aircraft
- Airframe total time: 172 hours
- Last inspection: condition inspection, March 5, 2011
- Maximum gross weight: 1,200 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 503 UL DCDI (piston); 0 hours total
The flight
- Departed from: Neshkoro WI
- Destination: Neshkoro WI
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: a few clouds
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 1 | |||
| Passengers | 1 |
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 docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site 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 CEN11FA433.