What happened
On 21 August 2005, a Piper Pacer PA 20/22, registration G-APYI, was engaged in a ferry flight from a private airfield in Navan to Athboy, County Meath. During the initial takeoff, the pilot noted a tendency for the aircraft to swing to the left, which was initially managed using right rudder input. However, during the climb out, the pilot realized that the right rudder pedal had reached the end of its travel without successfully correcting the leftward yaw.
Despite this developing control issue, the pilot proceeded to land at Ballyboy. During the landing roll on runway 29, a light crosswind from the left caused the aircraft to weathercock. Due to the lack of effective right rudder control, the aircraft veered off the runway, striking a wire fence and coming to rest with a wing embedded in a hedge. The pilot was uninjured, but the aircraft sustained damage to the propeller tips, wing surfaces, and the landing gear.
The investigation
The investigation focused on the functionality of the aircraft's control system and the condition of the rudder pedals. While the pilot initially believed the controls were functioning correctly, a detailed examination of the rudder assembly revealed that the pilot's right pedal did not provide full or free movement of the rudder cable.
Investigators examined the hardware connecting the pilot's right pedal to the rudder bar. Although the bolt used was the correct size, the hole within the torque tube had become enlarged and oversized. This degradation created significant play within the pedal system, preventing the pilot from applying the necessary rudder deflection to counteract the aircraft's yawing tendency.
Findings
- The primary cause of the runway excursion was excessive play between the pilot's right rudder pedal and the torque tube.
- This mechanical failure was due to the elongation of the bolt hole in the torque tube.
- During the landing phase, the pilot lacked sufficient right rudder authority to maintain directional control against a crosswind.