Piper PA-11 Cub Special — Service Bulletins

This document is an Airworthiness Directive (AD) issued by the FAA concerning certain Piper aircraft, including the Piper PA-11. It addresses safety concerns related to rudder posts made from 1025 carbon steel, which have been linked to structural failures in flight. The directive mandates the replacement of these rudder posts with ones made from 4130N low-alloy steel to mitigate the risk of rudder failure, which could lead to loss of control during flight. The AD is effective from March 20, 2025, and aims to enhance the safety of the affected aircraft models by ensuring compliance with updated material standards. The document includes background information on the incidents that prompted the AD, as well as compliance timelines for affected aircraft owners and operators.

• Rudder posts made from 1025 carbon steel must be replaced with 4130N low-alloy steel.
• The AD is effective from March 20, 2025.
• Affected aircraft include Piper PA-11, PA-12, PA-14, and others.
• Failure of the rudder post can lead to loss of control during flight.
• Compliance timelines vary based on aircraft model and configuration.