Cessna 172P N62283 accident near Winder, Georgia

Probable cause

Maintenance personnel’s failure to detect the damaged aileron cable during the most recent inspections, which resulted in the separation of the aileron control cable and subsequent loss of airplane control.

NTSB analysis

The flight instructor and student pilot completed several touch-and-go landings and on the final circuit in the traffic pattern, while on the final approach, the student pilot turned the yoke, and felt a sensation like the aileron cable disconnecting. The flight instructor took control of the airplane and noted that he could turn the control yoke 360° without a response from the airplane. Having no aileron control, the airplane veered to the right and descended into trees. A post-impact fire ensued that destroyed the airplane.

Examination of the wreckage revealed that there was a break in the aileron control cable system near the right control column. A metallurgical examination of the break in the aileron control cable revealed that the mating fracture surfaces exhibited a flattened area over more than half the cable cross-section, with the remainder of the wires exhibiting features consistent with overstress fractures. The wires in the flattened area exhibited consistent, parallel streaks and witness marks. These marks may indicate wear from rubbing against an adjacent component in this area or they may be consistent with some partial cutting operation.

If rubbing of the cable was creating wear, this process would have removed material wire-by-wire, and strand-by-strand over time. The remaining wires would have fractured from tensile overstress when there were no longer enough intact wires to carry the stress. It’s likely the overstress fracture occurred during the final leg of the traffic pattern, which was consistent with reports from the pilot and flight instructor that the flight controls no longer functioned properly during the final landing approach.

According to maintenance records, the airplane was inspected, in accordance with the maintenance manual and Part 43 appendix D, 9 times during the 13 months before the accident. According to both inspection checklists, the aileron control cable should have been inspected and found unairworthy at some point due to its condition. Therefore, it’s likely maintenance personnel overlooked the damaged aileron control cable during the most recent inspections.

Text from the NTSB. Open the NTSB docket for ERA22LA167 for the full record.