What happened
On 3/30/2020, a Kit Planes for Africa Bush-Baby, registration ZU-BEA, was conducting a private flight near Klerksdorp, North West Province. The flight, which involved a pilot and one passenger, was intended to be a short excursion to view animals on a local farm before returning to the Plot 49 Airstrip. The flight proceeded without incident until the aircraft returned to the airstrip for landing.
During the landing roll on Runway 36, the left-hand main landing gear axle fractured at the in-board wheel bearing area. This structural failure caused the gear strut to dig into the ground, forcing the aircraft to nose over and come to rest in an inverted position. The impact resulted in substantial damage to the aircraft, while the pilot and passenger sustained minor injuries.
The investigation
SACAA AIID investigators examined the aircraft's maintenance history and the physical condition of the landing gear. The investigation confirmed that the aircraft was operating under the Experimental Aircraft Category. Records showed that the aircraft had accumulated 582.5 total airframe hours and had undergone a 50-hour inspection approximately five months prior to the accident.
Post-accident inspections of the left gear assembly revealed a pre-existing crack in the in-board wheel bearing area. While the aircraft's maintenance person had previously inspected the axles during a brake replacement in 2018, no anomalies were detected at that time. Furthermore, because of the aircraft's experimental classification, there was no regulatory requirement for non-destructive testing (NDT) of the axles, and no such testing had been performed.
Findings
- The left-hand main landing gear axle failed due to fatigue.
- A pre-existing crack was present on the in-board wheel bearing area of the wheel assembly.
- The failure was likely precipitated by the axle being subjected to hard landings over time, which may have caused an overstress fracture.
- The aircraft was an amateur-assembled kit, and the specific origin of the wheel and brake system could not be definitively confirmed by the manufacturer.