What happened
On 24 October 2024, a Cessna 310Q, registration ZS-III, was conducting a private flight at Secunda Aerodrome (FASC) in Mpumalanga. The flight, operated under Part 91 regulations, involved a pilot and three passengers. After approximately 30 minutes of flight time under visual meteorological conditions, the pilot attempted a touch-and-go landing on Runway 29.
During the maneuver, the pilot noted that the landing gear would not retract, although the cockpit indicated the gear was down and locked. Deciding to perform a full-stop landing instead, the pilot touched down and immediately felt a heavy jerk to the left accompanied by a loud noise. While the pilot managed to maintain the runway heading using the right brake and rudder, the aircraft eventually veered left and came to a halt. The left main landing gear collapsed, causing the left wing to rest on the grass adjacent to the runway. There were no injuries to the occupants, but the aircraft sustained substantial damage.
The investigation
SACAA AIID investigators examined the wreckage and the aircraft's maintenance history. Inspection of the left main landing gear revealed that the lower torque link had dislodged from the assembly, causing the wheel assembly to rotate 180 degrees. While the upper torque link's attachment hardware—including the bolt, nut, and washers—remained secured, the lower link had pulled through the assembly.
Records indicated that the aircraft had been involved in a similar landing gear collapse at Rand Aerodrome in April 2023. Investigators also noted that the accident was reported to the AIID two weeks after the occurrence, which was a violation of the 24-hour reporting requirement and resulted in the loss of critical evidence.
Findings
- The primary cause of the collapse was the separation of the upper and lower torque links due to excessive wear on the two retaining washers.
- The failure of the trunnion support was caused by the heavy overload resulting from the gear collapse.
- A contributing factor was the possibility that the necessary hardware (nut, spacer, washers, bolt, and split pin) was not replaced during the repairs following the previous accident in April 2023.
- The aircraft's maintenance logs showed compliance with a 2002 Service Bulletin regarding washer thickness, but the mechanical failure occurred regardless.