Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Kansas City, Missouri
Federal Aviation Administration / Flight Standards District Office; Kansas City, Missouri
Investigation Docket - National Transportation Safety Board:
Location: Lee's Summit, MO
Accident Number: CEN20CA184
Date & Time: 05/19/2020, 1645 CDT
Registration:N41LR
Aircraft: Rhoads, Larry E Sopwith Baby
Aircraft Damage: Substantial
Defining Event: Loss of control on ground
Injuries: 1 None
Flight Conducted Under: Part 91: General Aviation - Flight Test
Analysis
The pilot departed on the airplane's initial test flight in a tailwheel-equipped biplane. At the speed when the tailwheel lifted from the runway, the airplane began an uncommanded left roll. The pilot attempted to arrest the roll moment but was unsuccessful. He aborted the takeoff but lost control of the airplane as the settled down in a crab resulted in the airplane exited the side of the runway, the failure of the left landing gear, and subsequent nose over of the airplane. Substantial damage was sustained to the lower left wing.
The airplane builder conducted a post-accident examination and reported that the right wing had a different "angle-of-attack" then the other wings, due to a construction error. This difference likely resulted in the uncommanded left roll during takeoff. This rolling tendency was not detected during the previous four high-speed taxi tests.
The pilot departed on the airplane's initial test flight in a tailwheel-equipped biplane. At the speed when the tailwheel lifted from the runway, the airplane began an uncommanded left roll. The pilot attempted to arrest the roll moment but was unsuccessful. He aborted the takeoff but lost control of the airplane as the settled down in a crab resulted in the airplane exited the side of the runway, the failure of the left landing gear, and subsequent nose over of the airplane. Substantial damage was sustained to the lower left wing.
The airplane builder conducted a post-accident examination and reported that the right wing had a different "angle-of-attack" then the other wings, due to a construction error. This difference likely resulted in the uncommanded left roll during takeoff. This rolling tendency was not detected during the previous four high-speed taxi tests.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The airplane builder's improper installation of the lower right wing which resulted in an uncommanded left roll and the subsequent loss of control.
Findings
Aircraft Flight surfaces (wing) - Design
Personnel issues Aircraft control - Pilot
Factual Information
History of Flight
Takeoff Loss of control on ground (Defining event)
Pilot Information
Certificate: Flight Instructor; Commercial
Age: 72, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): Helicopter
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): Airplane Single-engine; Helicopter
Toxicology Performed: No
Medical Certification: Class 3 With Waivers/Limitations
Last FAA Medical Exam: 07/15/2019
Occupational Pilot: No
Last Flight Review or Equivalent: 02/12/2020
Flight Time: (Estimated) 2186 hours (Total, all aircraft), 0.1 hours (Total, this make and model), 1345 hours (Pilot In Command, all aircraft), 4 hours (Last 90 days, all aircraft), 3 hours (Last 30 days, all aircraft)
Aircraft and Owner/Operator Information
Aircraft Make: Rhoads, Larry E
Registration: N41LR
Model/Series: Sopwith Baby
Aircraft Category: Airplane
Year of Manufacture: 2019
Amateur Built: Yes
Airworthiness Certificate: Experimental
Serial Number: 001
Landing Gear Type: Tailwheel
Seats: 2
Date/Type of Last Inspection: 01/31/2020, Annual
Certified Max Gross Wt.: 1400 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time:
Engine Manufacturer: Rotec
ELT: C126 installed, not activated
Engine Model/Series: 3600
Registered Owner: Emerald Hills Farm LLC
Rated Power: 150 hp
Operator: On file
Operating Certificate(s) Held: None
Meteorological Information and Flight Plan
Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KLXT, 997 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 1653 CDT
Direction from Accident Site: 83°
Lowest Cloud Condition:Clear
Visibility: 10 Miles
Lowest Ceiling:None
Visibility (RVR):
Wind Speed/Gusts: 3 knots /
Turbulence Type Forecast/Actual: None /
Wind Direction: 10°
Turbulence Severity Forecast/Actual:
Altimeter Setting: 29.94 inches Hg
Temperature/Dew Point: 20°C / 11°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Lee's Summit, MO (LXT)
Type of Flight Plan Filed: None
Destination: Lee's Summit, MO (LXT)
Type of Clearance: None
Departure Time: 1645 CDT
Type of Airspace:
Airport Information
Airport: LEE'S SUMMIT MUNI (LXT)
Runway Surface Type: Concrete
Airport Elevation: 1004 ft
Runway Surface Condition:
Runway Used: 36
IFR Approach: None
Runway Length/Width: 5501 ft / 100 ft
VFR Approach/Landing: None
Wreckage and Impact Information
Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 38.959722, -94.373889 (est)
Who signed it off to fly. Surely the wing angle of incidence was checked?
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