Wednesday, August 3, 2016

Sonex Limited Waiex, N12YX: Accident occurred August 03, 2016 near Fond Du Lac County Airport (KFLD), Fond du Lac County, Wisconsin

National Transportation Safety Board - Aviation Accident Preliminary Report: 


FAA Flight Standards District Office: FAA Milwaukee FSDO-13

NTSB Identification: CEN16LA302
14 CFR Part 91: General Aviation
Accident occurred Wednesday, August 03, 2016 in Fond du Lac, WI
Aircraft: SONEX LIMITED WAIEX, registration: N12YX
Injuries: 2 Serious.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On August 3, 2016, about 1155 central daylight time, a Sonex Limited Waiex airplane, N12YX, impacted terrain following a partial loss of engine power near the Fond du Lac County Airport (KFLD), Fond du Lac, Wisconsin. The private rated pilot and flight instructor were both seriously injured. The airplane was substantially damaged. The airplane was registered to and operated by Sonex Ltd under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan.

According to preliminary information obtained by investigators, the pilots were performing touch-and-go landings at KFLD. Shortly after takeoff, the pilots reported a loss of engine power. During the forced landing, the airplane collided with a transmission line and impacted terrain. An inspection of the airplane revealed substantial damage to the fuselage and both wings.

The airplane was retained for further examination.

A pilot and passenger practicing landings and takeoffs at the Fond du Lac County Airport Wednesday experienced engine failure when their plane lost altitude, hit a guide wire and crashed, the Fond du Lac County Sheriff's Office said Thursday.

A complete investigation into the crash of the single-engine plane is being conducted by the National Transportation and Safety Board. The official findings could take months to complete, said airport manager John Wehner.

The passenger, David Plathe, 60, of Dedham, Massachusetts, was flown from the scene by Flight for Life to ThedaCare Regional Medical Center in Neenah. He was released Thursday, according to a hospital spokesperson.

St. Agnes Hospital could not release information on the condition of the 73-year-old pilot, Thomas Helm from Neenah, the spokesperson said.

The plane, owned by Sonex Aircraft LLC in Oshkosh, took off from the airport shortly before 12:30 p.m. Helm, who was training Plathe how to fly the aircraft, attempted to return to the airport but did not have enough altitude and struck a power line before crashing into the edge of a corn field southwest of the airport property along Esterbrook Road.

This was the second plane crash in Fond du Lac within a week's time. On July 30, a time when the Fond du Lac County Airport was busy due to EAA AirVenture in Oshkosh, a single-engine airplane crashed in the northwest corner of the airport. David Spencer and Rafael Chavez from Santa Fe, New Mexico, were critically injured.

Wehner said the two crashes in one week are not related to airport operations. The crashes represent a streak of bad luck, he said. The July 30 crash was the first at the airport since the 1990s.

Wisconsin State Patrol, Fond du Lac Fire/Rescue and the Fond du Lac Fire Department and First Responders aided at the scene.


FOND DU LAC - Fond du Lac was the scene Wednesday of a second plane crash within a week's span.

A single-engine Sonex airplane that took off from Fond du Lac County Airport shortly before 12:30 p.m. clipped a power line and dropped almost instantly about 40 feet to the ground, injuring both the pilot and passenger.

Alisha Adams, who lives at N6311 Esterbrook Road, was about to go swimming with her kids for the day when she heard what she thought was a tractor crash.

“All of the sudden I heard a (sound) and a loud explosion,” Adams said. Looking out her side window, she saw the downed aircraft and people nearby, who had rushed to the scene to give aid.

The pilot, a man in his 70s from the Neenah area, was transported by ambulance to St. Agnes Hospital in Fond du Lac. The passenger, a man in his 50s, was transported by Flight for Life to ThedaCare Regional Medical Center in Neenah, according to Fond du Lac County Sheriff’s Capt. Rick Olig.

Apparently the plane, owned by SONEX Aircraft LLC out of Oshkosh, was practicing takeoffs and landings and had taken off heading west when it banked and the wing caught a guide wire of an electrical power line, spinning the plane backward.

It came down on its belly at the edge of a cornfield skirting Esterbrook Road, the first major street west of the airport, near Grove Street. Both men were conscious and able to answer questions, Olig said.

Mark Schaible, general manager at Sonex, said the pilot was on contract with the company providing transition training to a customer who had purchased a Sonex aircraft kit to build his own plane.

Customers often train with one of Sonex’s certified flight instructors to gain familiarity with the aircraft before flying it on their own, Schaible said.

“Right now our concern is with the occupants (of the plane) and have learned both are in stable condition,” Schaible said Wednesday afternoon.

The same type of company-owned Sonex plane crashed in Oshkosh on June 2, 2015, killing Sonex CEO Jeremy Monnett and assembly mechanic Mike Clark, a new employee with the company. Schaible said he couldn’t speak as to whether the accidents were similar.

Last week, on July 30, as Fond du Lac County Airport was busy with flyers arriving for EAA AirVenture in Oshkosh, a single-engine airplane crashed in the northwest corner of the airport. David Spencer and Rafael Chavez from Santa Fe, New Mexico, were critically injured.

Esterbrook Road was closed Wednesday between Forest Avenue Road and Rogersville Road while emergency and power crews from Alliant Energy work at the scene.

Story and video:

TOWN OF FOND DU LAC (WLUK) -- Two people were hospitalized following a plane crash in the Town of Fond du Lac Wednesday afternoon.

The Fond du Lac County Sheriff's Office says the crash happened around 12:15 p.m. just south of the intersection of Esterbrook Road and Grove Street in the Town of Fond du Lac. That's just west of the Fond du Lac County Airport.

The pilot, a Neenah man believed to be in his 70s, was taken by ambulance to St. Agnes Hospital in Fond du Lac. The passenger, a man believed to be in his 50s, was airlifted to ThedaCare Regional Medical Center-Neenah. He was listed in good condition Wednesday afternoon.

According to the sheriff's office, the pilot was practicing taking off and landing at the airport. The plane had just taken off, headed west, when the wing tip clipped a power line, causing the plane to slingshot into the ground.

The two-seat experimental aircraft is owned by Sonex Aircraft of Oshkosh.

Authorities are recommending drivers avoid the area as utility crews repair the power lines.

Story and video:


gretnabear said...

Why are the flaps fully extended?

Anonymous said...

Sonex flaps are manually actuated with a lever that fits into detents. In an accident, it wouldn't take much to knock the lever out of the detent and gravity will do the rest. I don't think you can draw any conclusion about their position in flight from the pictures.

Anonymous said...

Sonex = poorly designed/built. It's underpowered, serious/critical issues with cooling, restricted/limited forward visibility, lousey nose gear, range is pitiful. Realistically it's a one (1) person aircraft.

Anonymous said...

The nose gear certainly is weak, since it's nonexistent in a tailwheel airplane like the accident Sonex, the forward visibility is restricted on the ground in the tailwheel version compared to a tricycle 172 but pretty good compared to other tailwheel planes, it's definitely underpowered when the engine cuts out, but when running it's a plane that has multiple engine options of different power levels, cooling would also depend on engine, poorly built only if the individual builder does a terrible job, and the range certainly is pitiful compared to the offerings from Boeing, but does well compared to aircraft of this class.

Anonymous said...

I'm sorry, Aerovee powered Sonex aircraft are accidents waiting to happen. I watched one crash at Oshkosh a few years ago during a go around. The little Aerovee was screaming away, but it was behind the power curve and couldn't fly out of its own way. Monnet designed a great airplane but refuses to scale it up any to use a more reliable power plant... can you imagine how many O320 sonexes would be flying today?

As Sonex continues to push the now ancient idea of VW conversion, these accidents will continue. I would start building an O320 scale version tomorrow if it existed. The Aerovee liability will catch up to the company and end it. Unfortunately it is just a matter of time.

Anonymous said...

I was unable to find any information of a crash that matches your description. I've flown my Aerovee powered Sonex at or near gross weight many times and it flew fine and I could easily perform a go around without finding myself in the situation you describe. If you carry enough speed to flare gracefully near the beginning of the runway, you have enough speed and power to get out of any runway you can take off from.

The Sonex fills a niche for me and many others. If I wanted or could afford to build an O320-powered metal airplane, I'd probably build an RV. I don't know if you are a builder, but suggest there's enough options out there that you could find something you're comfortable with building, also.

The Jabiru 3300 provides 50% more power and recently many other engines have become officially-sanctioned by Sonex.

Anonymous said...

Aerovee is a joke. Aerocarb makes it a bad joke. The Turbo makes it a bathroom joke. My Sonex has a custom cowl, 3300, fuel injection, proper fairings, proper tailwheel, real tires....etc. Its one of the best airplanes around in this configuration...the company disowned me for making it work out the Brandex aircraft!

TheSonOf Liberty said...

The passenger who was learning to fly this aircraft he had just purchased is a friend of mine. He said that they got up to about 300ft and the engine started to sputter and then just cut out. The training pilot took over the control's tried to bank the plane left to get back to the runway but they lost altitude fast and hit the power line and crashed. Besides some stitches and bump's and bruises my buddy Dave is in good health.