What happened
On March 8, 2016, during a scheduled 100-flight-hour periodic inspection at the OKL PRz technical base at EPRZ (Rzeszów-Jasionka), significant structural damage was identified on a PZL M-20-3 Mewa. The inspection revealed several missing rivets in the rear section of the right wing spar web, specifically in the area near the attachment point for the rear main landing gear strut. The damage was characterized by rivets that had been sheared or fractured at both the upper and lower flanges of the spar web. Additionally, the inspection found deformation in the form of buckling on both the upper and lower surfaces of the right wing in the vicinity of the spar damage.
The investigation
The investigation, conducted by the operator, examined the physical state of the aircraft and its maintenance history. The aircraft had accumulated a high number of flight cycles, totaling 9,129 landings. The investigation focused on the nature of the rivet failures and the resulting skin deformation to determine the origin of the structural compromise.
Findings
- The primary cause of the incident was a hard landing on the right main landing gear.
- The aircraft's extensive operational history, stemming from its use in flight training, contributed to the incident. The high number of flight cycles and the frequent exposure to hard landings by student pilots increased the likelihood of such structural fatigue or impact damage.