Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to Jetstream Aircraft Limited (JAL) HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes. The proposed action would require inspecting (one-time) the threaded portion of the aileron mounting spigots for cracks, replacing any cracked spigots, and replacing the securing nut assemblies with newly designed special nut assemblies and new split pins. The proposed action is prompted by reports of cracked mounting spigots caused by stress corrosion. The actions specified by the proposed AD are intended to prevent damage to the aileron control systems, which if not detected and corrected, could cause loss of lateral control and eventual loss of control of the airplane.