What happened
On 13 November 2021, a Piper 28R-201T Cherokee Arrow III, registration ZS-JZP, was conducting a private flight from Pietermaritzburg Aerodrome to the Magwa Tea Estate near Lusikisiki. The flight, operated under Part 9-1 regulations, proceeded under clear skies and good visibility.
Upon arriving at the unpaved airstrip, the pilot executed the standard joining procedures for the unmanned field. After completing all necessary downwind checks—including verifying flap settings and landing gear extension—the pilot touched down at approximately 75 knots. While the main landing gear initially held, the nose gear subsequently collapsed. This caused the propeller to strike the ground and the aircraft's lower engine cowling to skid across the grass runway. There were 0 fatalities and no injuries to the pilot or passenger, though the aircraft sustained substantial damage.
The investigation
An inspection by an Approved Maintenance Organisation (AMO) revealed that the down lock assembly hook had fractured and broken off. This failure left only the springs to maintain the nose gear in its locked position. The investigation also noted a bent hydraulic actuator shaft, further indicating the severity of the failure.
Investigators examined the component and found evidence suggesting that a fatigue crack may have initiated the failure. While the cockpit indication system correctly showed the gear as down and locked, the broken hook meant the assembly lacked the structural support necessary to remain locked upon the impact of landing. The unpaved nature of the runway was also considered a contributing factor to the collapse.
Findings
- The primary cause of the nose gear collapse was the fracture of the nose gear lock assembly hook, likely due to metal fatigue.
- The broken hook prevented the gear from remaining securely locked once the nose wheel transitioned to the ground.
- The unpaved surface of the Magwa Tea Estate runway may have contributed to the mechanical failure of the assembly.
- The aircraft's landing gear lock assembly is an on-condition component that only requires visual inspection every 50 hours, which may have allowed the fatigue crack to go undetected.