18TB4-1 Alaska Gear Company Piper Square 4130 Chromoly Rudder Assembly for Experimental PA-18-Style Aircraft | 18TB41

The Alaska Gear Company 18TB4-1 square rudder assembly is designed for experimental PA-18-style aircraft and is manufactured with a 4130 chromoly steel rudder post, addressing the material-related safety concerns identified in FAA AD 2025-02-11.

AD 2025-02-11 identifies fatigue and corrosion issues associated with rudder posts made from 1025 carbon steel. This square-style rudder post is constructed from 4130 chromoly steel, providing improved fatigue resistance, corrosion durability, and long-term structural integrity compared to legacy materials.

The rudder assembly is supplied uncovered and powder-coated and includes pre-installed brass bushings to reduce installation time. This configuration includes a rear navigation light cup and does not include a strobe mounting location.