What happened
On June 30, 2017, a Piper PA-18-180M, registration HB-POD, was conducting a training flight at Hausen am Albis (LSZN) under Visual Flight Rules. The flight involved a pilot and a flight instructor performing a proficiency check. After completing initial landings at Hausen am Albis and a subsequent flight to Triengen (LSPN), the crew returned to Hausen am Albis to perform a power-off approach on runway 27 for instructional purposes.
During the landing phase, the aircraft initially made contact with the left main gear and the tailwheel. As the right main gear touched the runway, the aircraft began to deviate a few degrees to the left of the runway centerline. The pilot attempted to correct this deviation using the right rudder. However, the correction proved excessive, prompting the pilot to apply left rudder to counter the movement. As the aircraft rolled further to the left, the pilot applied the right main brake. This action caused the aircraft to pivot around its vertical axis in a ground loop, leading the left wing tip to strike the runway surface before the aircraft came to a stop. There were no injuries to the two occupants, though the aircraft sustained light damage.
The investigation
The investigation examined the pilot's recent flight history and the sequence of control inputs during the landing. It was noted that the pilot had previously experienced two runway excursions during a proficiency check in October 2016. Additionally, during a landing training session in the spring of 2017, the pilot had voluntarily aborted a training session, which led to a temporary revocation of solo flight privileges for this specific aircraft. The investigation focused on the mechanical and aerodynamic factors during the power-off approach and the subsequent pilot inputs that led to the loss of directional control.