What happened
On March 4, 2007, a Mudry CAP-10B, registration I-AKRO, was conducting a training flight for SEP LAND rating renewal. The flight originated from Thiene airport, with the intention of performing several touch-and-go maneuvers at Vicenza airport before returning to Thiene.
During the second touch-and-go maneuver performed by the student pilot, the aircraft experienced a heavy impact with the runway. The touchdown occurred with the tailwheel hitting the pavement before the main landing gear. This impact caused significant damage to the tailwheel assembly. Although the pilot was able to continue the maneuver and take off, the instructor, noting the violent nature of the impact, decided to perform a low pass over Thiene to inspect the gear. Upon confirming the abnormal position of the tailwheel via radio, the instructor took control and diverted to the paved runway at Vicenza. An emergency landing was declared, and the aircraft came to a stop in the center of the runway with no further damage.
The investigation
The ANSV examined the aircraft's maintenance history and the physical condition of the broken component. The investigation revealed that the tailwheel shock absorber had been replaced just one day prior to the accident. A fractographic analysis of the broken part showed plastic deformation around the shock absorber mounting hole, which acted as a stress concentelator. The fracture surface exhibited a dark gray, coarse grain texture, which is characteristic of a failure caused by a single, massive overload.
Findings
- The primary cause of the incident was an incorrect aircraft attitude during landing.
- This improper attitude caused the tailwheel to absorb a dynamic load exceeding the material's structural limits.
- There were no pre-existing material defects or evidence of progressive fatigue failure.
- Maintenance records for the aircraft were found to be in order, and the flight crew was properly qualified.