What happened
On 3 February 2022, a Cessna 177RG aircraft, registration ZS-IIZ, was conducting a private flight from Brits Aerodrome to Grand Central Aerodrome (FAGC) in Gauteng. The flight, operated under Part 9 and involving two occupants, proceeded without incident until the aircraft returned to FAGC for landing. After completing two successful touch-and-go maneuvers, the pilot attempted a full-stop landing on Runway 35.
During the landing roll, as the aircraft decelerated at approximately 75 knots, the nose gear suddenly collapsed. The nose of the aircraft pitched downward, causing the propeller to strike the runway surface. The aircraft slid roughly 40 meters before coming to a halt. While there were no injuries to the pilot or passenger, the aircraft sustained substantial damage.
The investigation
SACCA AIID investigators examined the aircraft at a maintenance organization in Wonderboom Aerodrome. Post-accident inspections of the cockpit revealed that the landing gear lever was in the down position and the green indicator lights had been illuminated prior to the event. The unsafe gear warning horn was also found to be functioning normally.
Technical examinations focused on the hydraulic system and the landing gear pump motor. While the hydraulic pressure was adequate and the main landing gear functioned correctly during testing, investigators discovered significant heat damage within the gear pump motor. The motor's electrical leads and armature showed signs of excessive heat, which had caused the melting of pigtail bonding and the detachment of a brush spring.
Records also revealed that during a previous inspection in September 2021, the main landing gear had exhibited intermittent operation due to worn solenoid brackets. Although the pump motor had been overhauled and refitted in October 2021, the investigation looked into the continuous operation of the pump motor leading up to the incident.