On August 21, 2011, at 1514 central daylight time, a Hendryx/Wiley Super Rebel experimental amateur-built single-engine airplane, N540AF, sustained substantial damage during a forced landing following an in-flight failure of the aileron cable near La Porte City, Iowa. The private pilot, who was the sole occupant and registered owner, sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight departed the Nichols Airport, La Porte City, Iowa, approximately 1425.

According to the pilot, the accident flight was the third flight into the Phase 1 flight test program. While maneuvering the airplane at 2,500 feet above ground level through a series of turns, the pilot noticed the control stick force increase, and then he heard a bang. Following the bang sound, the pilot had no aileron control authority. The pilot maintained some control via rudder inputs and executed a forced landing to a field. During the forced landing, the airplane nosed over and came to rest inverted.

A postaccident examination of the airplane revealed the firewall and fuselage were buckled. One of the aileron cable swages failed, which resulted in the loss of aileron authority. According to a Federal Aviation Administration inspector who examined the airplane, the cable swage failed due to an improper crimp. The cable was manufactured by the builder during the airplane build process.