Marathon, TX, USA
N73BH
HARTLINE J BON HARTLINE KITFOX III
The pilot and the passenger were departing on a local personal flight in the experimental amateur-built airplane. The pilot indicated that, during the takeoff climb, about 15 ft above the ground, the airplane violently rolled to the right. He applied full aileron and rudder opposite the direction of the roll, but the airplane continued to roll to the right, struck the ground with the right wing, and then impacted a tree. Postaccident examination of the airplane revealed that three of the four hinges connecting the right flaperon hanger rib were loose. The wooden material of the flaperon was found dry rotted where the hinges connected. The airplane had been flown about 3 hours in the 11 months before the accident. The airplane kit manufacturer had issued a service bulletin in 1991 that identified flaperon hanger rib failures on the model of the accident airplane. The service bulletin recommended the addition of an aluminum reinforcement on each flaperon hanger rib end. The accident airplane did not have the reinforcement installed and thus did not have the benefit of additional reinforcement in the attachment point area of the hinges.
On May 2, 2018, about 1100 central daylight time, an experimental, amateur-built Kitfox III airplane, N73BH, was substantially substantial damaged during a forced landing after takeoff from the 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 as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed throughout the area and no flight plan was filed for the flight. The local flight was originating at the time of the accident. The pilot reported that during takeoff, about 15 ft above the ground, the airplane rolled violently to the right. He applied full aileron and rudder opposite the direction of the roll, but the airplane continued to roll to the right. The airplane struck the ground with the right wing and then impacted a mesquite tree. Examination of the wreckage after the accident revealed that 3 of the 4 hinges connecting the right flaperon hangar rib were loose. The wooden (spruce) material of the flaperon appeared to by dry rotted where the hinges attached. According to records provided by the owner, the airplane had last flown about 6 months prior to the accident flight. Records showed that the airplane had about 3 hours of flight time since its most recent conditional airworthiness inspection which was performed on May 23, 2017. Denny Aerocraft Company Service Bulletin #9, dated September 12, 1991, had identified flaperon hangar rib failures on Kitfox models I, II, and III. The service bulletin recommended the addition of an aluminum reinforcement on each flaperon hanger rib end. The accident airplane did not have the reinforcement installed.
The failure of the flaperon hinge attachment point during takeoff, which resulted in a loss of airplane control. Contributing to the accident was the lack of reinforcement of the hinge attachment point in accordance with the manufacturer’s service bulletin.
Source: NTSB Aviation Accident Database
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