Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Milwaukee, Wisconsin
Sonex Aircraft LLC; Oshkosh, Wisconsin
Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf
Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms
Sonex Ltd: http://registry.faa.gov/N12YX
Location: Fond du Lac, WI
Accident Number: CEN16LA302
Date & Time: 08/03/2016, 1155 CDT
Registration: N12YX
Aircraft: SONEX LIMITED WAIEX
Aircraft Damage: Substantial
Defining Event: Powerplant sys/comp malf/fail
Injuries: 2 Serious
Flight Conducted Under: Part 91: General Aviation - Instructional
Analysis
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.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
A partial loss of engine for reasons that could not be determined during an examination of the engine.
Findings
Environmental issues
Wire - Contributed to outcome
Not determined
Not determined - Unknown/Not determined (Cause)
Factual Information
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 (FLD), 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 light, which operated without a flight plan. The airplane was departing FLD at the time of the accident.
According to information provided by the flight instructor, the pilots were performing takeoffs and landing on runway 27 at FLD. Shortly after takeoff, when the airplane was between 200 to 300 ft above ground level, they heard a sudden change in the engine noise. The instructor observed that the engine rpm was between 2,500 to 2,600 rpm, when the engine was previously performing about 3,100 rpm. The instructor took control of the airplane and began an immediate left turn for runway 15. The airplane would not maintain altitude, so he momentarily leaned the mixture which did not improve engine performance, so he returned the mixture to full rich, and performed a forced landing to a field. The airplane collided with an unseen transmission line and impacted terrain. A postaccident examination of the airplane revealed substantial damage to the fuselage and both wings.
An examination of the engine was conducted at Sonex under the auspices of the Federal Aviation Administration. A compression check of the engine found low compression of the number 1 and 2 cylinders. Examination of the exhaust valves found they displayed excessive wear.
Pilot Information
Certificate: Airline Transport; Commercial
Age: 73, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s): Glider; Helicopter
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): Airplane Multi-engine; Instrument Airplane
Toxicology Performed: No
Medical Certification: Class 2 With Waivers/Limitations
Last FAA Medical Exam: 04/04/2016
Occupational Pilot:
Last Flight Review or Equivalent: 05/14/2016
Flight Time: 29114 hours (Total, all aircraft), 35 hours (Total, this make and model), 24019 hours (Pilot In Command, all aircraft), 92 hours (Last 90 days, all aircraft), 9 hours (Last 30 days, all aircraft)
Pilot Information
Certificate: Private
Age: 64, Male
Airplane Rating(s): Single-engine Land
Seat Occupied:
Other Aircraft Rating(s): None
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed:
Medical Certification: Class 3 With Waivers/Limitations
Last FAA Medical Exam: 11/26/2014
Occupational Pilot:
Last Flight Review or Equivalent:
Flight Time:
Aircraft and Owner/Operator Information
Aircraft Manufacturer: SONEX LIMITED
Registration: N12YX
Model/Series: WAIEX NO SERIES
Aircraft Category:Airplane
Year of Manufacture: 2003
Amateur Built: No
Airworthiness Certificate: Experimental
Serial Number: 0001
Landing Gear Type: Tailwheel
Seats: 2
Date/Type of Last Inspection: 02/07/2016, 100 Hour
Certified Max Gross Wt.:
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 304.3 Hours as of last inspection
Engine Manufacturer: AMA/EXPR
ELT: Installed, not activated
Engine Model/Series: AeroVee
Registered Owner: SONEX LTD
Rated Power: 80 hp
Operator: SONEX LTD
Operating Certificate(s) Held: None
Meteorological Information and Flight Plan
Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KFLD, 807 ft msl
Observation Time: 1053 CDT
Distance from Accident Site: 0 Nautical Miles
Direction from Accident Site: 100°
Lowest Cloud Condition:
Temperature/Dew Point: 30°C / 22°C
Lowest Ceiling: Broken / 3100 ft agl
Visibility: 10 Miles
Wind Speed/Gusts, Direction: 4 knots, 270°
Visibility (RVR):
Altimeter Setting: 30.05 inches Hg
Visibility (RVV):
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: FOND DU LAC, WI (FLD)
Type of Flight Plan Filed: None
Destination: OSHKOSH, WI (OSH)
Type of Clearance: None
Departure Time:
Type of Airspace:
Airport Information
Airport: FOND DU LAC COUNTY (FLD)
Runway Surface Type: Asphalt
Airport Elevation: 808 ft
Runway Surface Condition: Dry
Runway Used: 27
IFR Approach: None
Runway Length/Width: 3602 ft / 75 ft
VFR Approach/Landing: None
Wreckage and Impact Information
Crew Injuries: 2 Serious
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 Serious
Latitude, Longitude: 43.770278, -88.501389 (est)
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.
Source: http://www.fdlreporter.com
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: http://www.fdlreporter.com
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: http://fox11online.com
Why are the flaps fully extended?
ReplyDeleteSonex 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.
ReplyDeleteSonex = 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.
ReplyDeleteThe 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.
ReplyDeleteI'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?
ReplyDeleteAs 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.
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.
ReplyDeleteThe 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.
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 properly...search out the Brandex aircraft!
ReplyDeleteThe 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.
ReplyDelete