Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-300 series airplanes. This proposal would require an inspection to detect fatigue cracking, base trim, and upper flange over-trim of the pulley brackets of the aileron control cables. It also would require, if necessary, replacement of the pulley brackets with new pulley brackets, and replacement of the two button-head rivets with flush-head rivets. This proposal is prompted by a review of the design of the flight control systems on Model 737 series airplanes. The actions specified by the proposed AD are intended to prevent fatigue cracking or fracturing of the pulley brackets, which could result in slack in the cables and consequent reduced ability of the flightcrew to control the aileron.