NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The flight instructor was conducting an aerobatic demonstration flight for a pilot-rated passenger, during which the flight instructor was demonstrating the airplane’s characteristics to the pilot. The flight instructor reported that he performed a spin maneuver, and during the recovery, he felt the tension in the rudder pedal become completely slack. The pedal moved completely forward, and he realized that the rudder cable must have separated. During the subsequent emergency landing at a nearby airport, the flight instructor could not maintain directional control, and the airplane slid off the right side of the runway.
A postaccident examination of the airplane revealed that the rudder cable had separated. The rudder cable showed signatures indicative of a failure due to tension overstress. Several of the wire strands on the cable were damaged by rubbing wear and were either completely worn through or nearly worn through, compromising the cross-section of the cable. The Federal Aviation Administration had issued a special airworthiness information bulletin (SAIB) for this airplane about 3 years before the accident to address similar rudder cable failures. The SAIB recommended that, to mitigate risk, cable inspections should be completed and a protective hose should be installed. A review of the maintenance logbooks found no record indicating that the SAIB had been implemented, and no protective hose was found. The SAIB was not mandatory, and the operator, which operated flights for paying passengers, including aerobatics and air combat demonstrations, chose not to the comply with it. If the operator had chosen to comply with the SAIB, the rudder cable may not have failed.