Aircraft and Operator
On 12 August 2000, at 0720 Z, a Cessna 172 RG, registration ZS-KSV, operated by Cape Aero Club, was conducting training in the D200 Training Area north of Cape Town. The aircraft had two persons on board: a student pilot and an instructor. Weather conditions were CAVOK.
Incident Sequence
During the training flight, the student and instructor were practicing an incipient spin. The student was recovering from a left-hand incipient spin with the right-hand rudder pedal depressed when a snap sound was heard and rudder control was lost. The aircraft recovered from the spin, and the pilot executed a safe landing at Cape Town International Airport.
Inspection Findings
Following the incident, inspection of the rudder pedal assembly revealed cracks in the rudder pedal sheet metal structure. Additionally, the torque tube bearings were worn, which could have resulted in excessive movement between the two torque tubes. This could have caused the torque tube gears to become misaligned, allowing the rudder control cables to slacken.
Probable Cause
The probable cause of the incident was that the torque tube bearings were worn to such an extent that it allowed the torque tube gears to become misaligned, which caused the rudder cables to slacken.