What happened
The accident occurred during the landing roll of a flight conducted for training purposes. The pilot, identified as a student, was executing a series of full stall landings as part of their practice regimen. Upon touchdown and while decelerating along the runway surface, the structural integrity of the left main landing gear axle was compromised. The axle fractured completely, causing the aircraft to lose support on that side. Consequently, the nose of the aircraft pitched forward violently, resulting in a nose-over attitude.
The investigation
Following the incident, safety board laboratories conducted a detailed mechanical examination of the failed component. Metallurgical analysis of the fracture surface provided critical evidence regarding the mode of failure. The examination revealed distinct characteristics consistent with fatigue failure, indicating that the axle had likely been subjected to cyclic stress over time prior to the final breakage. Further research into similar incidents or design flaws did not yield information suggesting this was a widespread problem affecting other aircraft of the same type or model.
Findings
The primary factor contributing to the accident was the structural failure of the left main landing gear axle. The laboratory findings confirmed that the axle failed due to fatigue, rather than an overload event during the landing impact itself. While the pilot was performing a standard training maneuver, the mechanical integrity of the landing gear was the limiting factor in preventing the nose-over. No evidence was found to suggest that this failure mode was common across similar aircraft models.
Safety message
This incident highlights the importance of rigorous maintenance inspections for landing gear components, particularly those susceptible to fatigue cracking. Regular non-destructive testing can help identify potential failures before they result in accidents during critical phases of flight such as landing.