Accident Overview
On May 2, 2018, approximately 1100 central daylight time, an experimental, amateur-built Kitfox III airplane, registration N73BH, was substantially damaged during a forced landing after takeoff from Stovall Ranch Airport (6TX9), Marathon, Texas. The airline transport pilot and one passenger sustained minor injuries. The airplane was privately owned and operated by the pilot under Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight was originating at the time.
Sequence of Events
According to the pilot, during takeoff at about 15 feet above the ground, the airplane rolled violently to the right. Despite applying full aileron and rudder opposite the direction of the roll, the airplane continued to roll to the right. The airplane struck the ground with the right wing and then impacted a mesquite tree.
Post-Accident Examination
Examination of the wreckage revealed that three of the four hinges connecting the right flaperon hanger rib were loose. The wooden (spruce) material of the flaperon appeared dry rotted where the hinges attached. Records provided by the owner indicated that the airplane had last flown about six months prior to the accident and had accumulated approximately three hours of flight time since its most recent conditional airworthiness inspection, performed on May 23, 2017.
Service Bulletin Compliance
Denny Aerocraft Company Service Bulletin #9, dated September 12, 1991, identified flaperon hanger rib failures on Kitfox models I, II, and III. The bulletin recommended installing an aluminum reinforcement on each flaperon hanger rib end. The accident airplane lacked this reinforcement.
Conclusion
The forced landing resulted from a loss of control due to a roll during takeoff, associated with loose and deteriorated flaperon hinge attachments.