What happened
On 2 August 2023, a private flight operating under Part 94 regulations experienced an accident during landing at Robertson Airfield in the Western Cape. The aircraft, a Flight Design CTSW with registration ZU-ELZ, had departed from Ceres Airfield earlier that day under clear visual meteorological conditions.
While the pilot was performing the landing roll on Runway 2 and the flight had been otherwise uneventful, the right main landing gear strut suddenly failed. This structural failure caused the aircraft to veer to the right of the runway centerline, eventually coming to a stop in nearby bushy terrain. The aircraft sustained substantial damage to the right wing tip and the right main landing gear. The pilot was able to disembark from the wreckage without any injuries.
The investigation
An inspection of the aircraft conducted by an approved person on 10 August 2023 identified a severe subsurface crack within the right main gear strut. This crack had propagated on one side of the component, accompanied by discoloration at the lower bolt attachment area.
Investigators examined the maintenance history and found that while the aircraft had undergone an annual inspection in June 2023, the specific inspection required by a 2008 Service Bulletin had been overlooked. Specifically, the inspection procedure required the removal of a bracelet to properly examine the area where the fatigue crack originated. Furthermore, there were no records indicating that a dye penetrant inspection had been performed during the most recent annual maintenance.
Findings
- The primary cause of the landing gear failure was a fatigue crack within the strut, which may have been exacerbated by galvanic corrosion at the lower attachment point.
- The approved person failed to comply with the mandatory Service Bulletin, which would have allowed for the detection of the crack.
- The maintenance procedure lacked specific details regarding the landing gear inspection within the 100-hour maintenance manual.
- The aircraft had accumulated 858 airframe hours, meaning the required 300-hour interval inspection should have been performed twice since the bulletin's implementation.