What happened
On July 26, 2016, an SMG-92 Turbo-Finist operated by Techniavia/Aerotech Slovakia was preparing for its seventh flight of the day, intended for skydiving operations, at Kielce-Masłów Airport (EPKA). After the parachutists had been boarded, the aircraft began taxiing. During this process, the tail of the aircraft descended to the ground. This impact caused the rear landing gear to break away from its attachment to the airframe, resulting in the failure of the gear' and its mounting structure. The incident also caused damage to the fuselage skin in the immediate vicinity of the landing gear attachment and dented the lower tip of the rudder.
The investigation
The investigation examined the structural integrity of the aircraft, noting a total airframe time of 2907.19 flight hours and 8958 cycles. The aircraft was at the end of a 600-hour inspection interval. Investigators analyzed the fracture surfaces of the rear landing gear mounting element, identifying three distinct zones: a corrosion penetration zone, a low-cycle fatigue zone, and a zone of immediate deformation. The investigation also noted that the aircraft, which was maintained by Jet Stream Kft, was primarily operated from grass airfields. It was observed that the rear landing gear on this specific model is attached directly to the airframe without any integrated shock absorption.
Findings
- Operational wear and tear led to fatigue phenomena within the rear landing gear and its mounting components.
- The design of the rear landing gear, which lacks an integrated damping or shock absorption system, contributed to the structural failure when subjected to operational stresses.
- The presence of corrosion and low-cycle fatigue at the attachment point was a significant factor in the structural compromise.