Airworthiness Directives; American Champion Aircraft Corp.

We propose to supersede Airworthiness Directive (AD) 2017-07- 10, which applies to certain American Champion Aircraft Corp. (ACAC) Model 8KCAB airplanes. AD 2017-07-10 requires fabrication and installation of a placard to prohibit aerobatic flight, inspection of the aileron hinge rib and support, and a reporting requirement of the inspection results to the FAA. This AD was prompted by a report of a cracked hinge support and cracked hinge ribs, which resulted in partial loss of control with the aileron binding against the cove. Since we issued AD 2017-07-10, ACAC redesigned the aileron hinge supports with a reinforcement kit to strengthen the supports and prevent future damage from developing. This proposed AD would require repetitive inspections of the aileron hinge support, installation of the aileron hinge support reinforcement kit, and incorporation of revised pages into the service manual. We are proposing this AD to address the unsafe condition on these products.