Incident Overview
On 25 January 2019 at 15:45 local time, a Piper L-4 (registration HB-ODZ) was conducting training landings at Birrfeld airfield (LSZF) for a tailwheel endorsement. The aircraft was operated by Motorfluggruppe PIPS and owned by a private individual. The crew consisted of a flight instructor and a pilot.
Sequence of Events
After a three-point landing on grass runway 26, during the deceleration phase, the flight instructor heard an abnormal noise from the rear fuselage and noticed a significant reduction in lateral maneuverability. The aircraft came to a stop on the grass. Upon exiting, the crew observed that the tailwheel had detached from the fuselage. With assistance from two other persons, the aircraft was moved to the airfield maintenance facility.
Findings
The tailwheel was attached to the rear fuselage via three spring leaves, which also served as shock absorbers, and was connected to the rudder by chains and springs. Inspection revealed that the spring leaves had fractured at a break point, causing the tailwheel to separate. The aircraft had accumulated 4220:42 hours total time since new and 5555 landings. The last 100-hour inspection was performed on 11 June 2018 at 4187:39 hours and 5391 landings.
Analysis and Conclusions
The serious incident was caused by failure of the tailwheel spring leaves, which led to the tailwheel separating from the fuselage. The high number of landings significantly contributed to the occurrence.
Damage and Injuries
The aircraft sustained light damage. No injuries were reported among the two occupants or any third parties.