Failure of the right rudder cable bends C-150
The pilot reported that, during approach, the automatic weather observation station at the airport in Pottsville, Pennsylvania, reported that the wind was from 170° at 12 knots.
He added there was “very massive choppy wind, including what could have been windshear, updrafts, and downdrafts.”
During the landing roll on Runway 11, a wind gust blew the Cessna 150 off the runway to the left. The pilot attempted to recover, but the plane hit a ditch, sustaining substantial damage to the fuselage and right wing.
The FAA inspector reported that a post-accident examination revealed that the rudder cable that passed along the left side of the fuselage was separated into three pieces. The rudder cable was covered in debris, which contained red fibers. The rudder cable was splayed and exhibited signatures consistent with tension overload.
The airplane’s illustrated parts catalog contained a diagram titled, “Rudder Control System Installation,” which displayed the cable along the left side of the fuselage cross over the right side of the airplane, in the tailcone section, and connect to the right side of the rudder horn, which provided right rudder authority.
The airplane’s most recent inspection was an annual, which was conducted six months before the accident. The FAA inspector interviewed the mechanic who performed theannual inspection, and the mechanic reported that, during inspections, he used manufacturer data and FAA Advisory Circular, AC 43.13-1B, “Acceptable Methods, Techniques, and Practices – Aircraft Inspection and Repair.” He further reported, multiple times, that he should probably “tighten up” his inspections.
AC 43.13-1B contained a section titled, “Cable System Inspection,” which stated the following: “Aircraft cable systems are subject to a variety of environmental conditions and deterioration. Wire or strand breakage is easy to visually recognize. Other kinds of deterioration such as wear, corrosion, and/or distortion are not easily seen; therefore, control cables should be removed periodically for a more detailed inspection.
“At each annual or 100-hour inspection, all control cables must be inspected for broken wire strands. Any cable assembly that has one broken wire strand located in a critical fatigue area must be replaced.”
It further stated: “Close inspection in these critical fatigue areas must be made by passing a cloth over the area to snag on broken wires. This will clean the cable for visual inspection, and detect broken wires if the cloth snags on the cable.”
It is likely that the red fibers found on the rudder cable were from a red cloth used to inspect the rudder cable during the annual inspection. It is also likely that, sometime during the flight or landing sequence, the right rudder cable separated, which subsequently restricted the pilot’s ability to recover from the loss of control during landing.
Probable cause: The failure of the right rudder cable and subsequent loss of directional control during landing.
NTSB Identification: GAA18CA020
This October 2017 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.