What happened
On July 28, 2015, a Cessna 152 was performing a touch-and-go landing at Lublin-Świdnik airport (EPLB). During the maneuver, immediately after the pilot applied power for the subsequent takeoff, the aircraft entered a state of intense vibrations. The pilot attempted to mitigate the issue by immediately reducing power, but the oscillations persisted.
In response to the instability, the pilot shut down the engine. Following consultation with the airport tower, the engine was restarted; upon the second application of power, the vibrations did not recur. The aircraft was then able to taxi safely to the parking apron.
The investigation
The PKBWL investigation focused on identifying the mechanical source of the sudden instability. The investigation established that the vibrations were not caused by pilot input or aerodynamic stall, but rather by a mechanical failure within the landing gear assembly. The technical examination identified a failure in the shimmy damper.
Findings
- The primary cause of the vibrations during the landing sequence was a failure of the o-ring seal within the shimmy damper.
- The failure of this specific component led to the loss of damping effectiveness, resulting in the observed oscillations.
- The issue was resolved by replacing the shimmy damper unit.