Event Description
During approach to the destination airport, the pilot received automated weather information indicating wind from 170° at 12 knots. The pilot characterized the wind as "very massive choppy wind, including what could have been windshear, updrafts, and downdrafts." While landing on runway 11, a wind gust pushed the airplane left of the runway. The pilot attempted to recover, but the airplane struck a ditch.
Damage
The accident resulted in substantial damage to the fuselage and right wing.
Postaccident Examination
A Federal Aviation Administration (FAA) inspector examined the airplane and found that the rudder cable running along the left side of the fuselage had separated into three pieces. The cable was covered in debris containing red fibers, and its ends were splayed with characteristics typical of tension overload. According to the airplane's illustrated parts catalog, this cable crosses to the right side in the tailcone and connects to the right side of the rudder horn, providing right rudder authority.
Pilot Report
According to the pilot, there were no mechanical failures or malfunctions before the accident that would have prevented normal operation.
Inspection Information
The airplane's most recent annual inspection occurred six months prior to the accident flight. The mechanic who performed that inspection told the FAA inspector he uses manufacturer data and FAA Advisory Circular AC 43.13-1B. He also stated multiple times that he should probably "tighten up" his inspections.
Advisory Circular Guidance
FAA Advisory Circular AC 43.13-1B, titled "Acceptable Methods, Techniques, and Practices – Aircraft Inspection and Repair," includes a section on cable system inspection. It notes that aircraft cable systems are subject to deterioration, and while broken wire strands are visually recognizable, other issues like wear and corrosion are not easily seen. It recommends that at each annual or 100-hour inspection, all control cables be inspected for broken wire strands, and any assembly with a broken strand in a critical fatigue area must be replaced. The circular further states that close inspection in critical fatigue areas should involve passing a cloth over the area to snag on broken wires, which both cleans the cable and detects broken wires.