Amateur-built WAIEX accident near Fond Du Lac, Wisconsin, August 3, 2016
On August 3, 2016 at about 4:55 pm local time, a 2003 amateur-built WAIEX, registered N12YX, was substantially damaged in an accident during takeoff near Fond Du Lac, Wisconsin (Fond Du Lac County airport). It was an instructional flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A partial loss of engine for reasons that could not be determined during an examination of the engine.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 3, 2016 · about 4:55 pm local time
- Place
- Fond Du Lac, Wisconsin · Fond Du Lac County · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built WAIEX NO SERIES, built 2003
- Registration
- N12YX · no longer on the register · serial 0001
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Shortly after takeoff on an instructional flight, the pilots heard a sudden change in engine noise. The instructor scanned the engine instruments and observed that the engine rpm was lower than expected. The instructor took control of the airplane and attempted to return to the airport. The airplane was not able to maintain altitude, and the instructor could not restore engine power to full. Unable to reach the airport, the instructor initiated a forced landing to a field. During the approach, the airplane collided with a power transmission line and impacted terrain. An examination of the engine found that the Nos. 1 and 2 exhaust valves displayed excessive wear. While such wear will result in a loss of engine power, it could not be determined what caused the sudden change in noise and engine power that the pilots experienced on the day of the accident.
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 takeoff defining event
- Loss of engine power (partial) during takeoff
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
- Environmental issues › Physical environment › Object/animal/substance › Wire › Contributed to outcome
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: instrument airplane; instrument: airplane; rotorcraft: glider; rotorcraft: helicopter
- Flight time: 29,114 hours in all; 35 in this make and model; 92 in the last 90 days; 9 in the last 30 days; 24,019 as pilot in command; 8,730 on instruments
- Last flight review: May 14, 2016
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: serious injuries
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Medical certificate: Class 3 (with waivers/limitations)
- Injury: serious injuries
The aircraft
- Airframe total time: 304.3 hours
- Last inspection: 100-hour inspection, February 7, 2016
- Seats: 2
- Landing gear: fixed
- Engine: Ama/Expr AeroVee (piston); 0 hours total
- Operator: Sonex LTD
The flight
- Departed from: FLD Fond Du Lac WI
- Destination: OSH Oshkosh WI
- Flight plan: none
- Runway 27, 3,602 ft by 75 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 270° at 4 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,100 ft
- Temperature: 86°F (30°C), dew point 72°F (22°C)
- Altimeter: 30.04 inHg
- Observation at 3:53 pm from KFLD
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
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.