Amateur-built KITFOX III N73BH accident near Marathon, Texas

Probable cause

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.

NTSB analysis

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.

Text from the NTSB. Open the NTSB docket for CEN18LA157 for the full record.