What happened
The pilot reported encountering difficulties with the elevator controls while the aircraft was en route to its destination. Despite the mechanical interference, the pilot maintained control and successfully completed the flight, landing safely at the intended airport without further incident.
The investigation
Following the landing, a thorough post-landing inspection of the aircraft was conducted to determine the root cause of the control issues. Inspectors discovered significant ice formation within the tail section, specifically in the area surrounding the elevator control cables. Further examination revealed that the water drain holes and limbers, which are designed to evacuate water from this compartment, were completely clogged with fuzz-like fibers. This blockage prevented proper drainage, allowing water to accumulate and freeze, which subsequently interfered with the free movement of the elevator controls.
Findings
The primary factor contributing to the incident was the accumulation of ice in the tail section due to obstructed drainage systems. The clogged limbers and drain holes allowed moisture to remain in the structure during flight conditions conducive to icing. This mechanical interference highlights the importance of maintaining clear drainage paths in aircraft structures exposed to precipitation.