What happened
On 23 May 2025, a Piper PA-22-108, registration G-ARNE, was performing a private flight departing from Old Buckenham Airfield in Norfolk. During the initial climb, reaching approximately 400 ft, the pilot experienced a physical jolt and heard a distinct clunk. Upon inspecting the aircraft, the pilot discovered that the outboard section of the left aileron had partially separated from the wing.
Fearing a total loss of control, the pilot declared a MAYDAY. To manage the situation, the pilot performed a steady climb and assessed the aircraft's handling. By utilizing rudder inputs to minimize the need for aileron movement, the pilot successfully navigated a wide circuit to avoid populated areas and returned to land safely on Runway 07. There were no injuries to the pilot.
The investigation
Investigators examined the aircraft and found that the clevis pin for the left outboard aileron hinge was missing. The hinge bracket through which this pin passed showed signs of wear.
Further inspection of the aircraft's right outboard aileron hinge revealed that a non-standard clevis pin had been installed. This part was larger in diameter than the manufacturer-specified part and was also fitted into a worn hinge bracket. Maintenance records did not indicate when the pin had been replaced, suggesting the modification may have occurred prior to the current owner's acquisition of the aircraft.
Findings
- The left aileron hinge clevis pin was absent, though it remains unclear if the pin failed or if a lost split pin allowed it to migrate out of the assembly.
- The use of non-standard, oversized pins was likely employed to compensate for worn hinge brackets, avoiding the necessity of replacing the brackets with correct parts.
- The presence of an oversized pin on the right aileron suggests a pattern of using improper components to bypass standard repair procedures.