What happened
On 10 June 2009, a King Air 200C, registration ZS-PNZ, was conducting a mercy flight from Cape Town International Aerodrome to East London Aerodrome. During the flight, the crew identified a malfunction in the landing gear system when only two green lights illuminated in the cockpit, indicating the nose gear had failed to lock in the down position. Despite attempts to manually extend the gear, the nose undercarriage remained unsecured.
Due to the mechanical issue, the crew diverted to Lanseria Aer to access maintenance facilities. Before landing, the aircraft performed a low-level flyby at 100 feet to allow ground observers and investigators to visually confirm the gear status. The nose gear was confirmed to be unsafe. During the subsequent emergency landing on runway 06R, the aircraft touched down normally; however, as the aircraft decelerated approximately 350 meters into the landing roll, the nose gear slowly collapsed. The aircraft skidded on its nose and propellers for about 110 meters. There were no injuries to the two crew members or the two passengers on board.
The investigation
SACAA investigators examined the aircraft at Lanseria Aerodrome. The investigation focused on the landing gear assembly and the nose gear actuator. To facilitate recovery, the nose gear was manually secured in the down position so the aircraft could be towed to a hangar.
Technical inspections of the removed nose gear actuator revealed that the internal threads of the retract shaft had worn beyond permissible limits. This degradation was the primary reason the gear could not extend and lock correctly during the flight.