Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-300, - 400, and -500 series airplanes. This proposal would require modification of the system that detects a loss of tension in the cable controlling the flaps by removing the shim from behind the bracket for the proximity switch; and by trimming this bracket. This proposal is prompted by reports that the bracket could impair the movement of a pulley arm mechanism, ultimately preventing the detection system from operating. The actions specified by the proposed AD are intended to prevent such impairment, which could result in movement of the flaps without action by the pilot, and ultimately cause reduced controllability of the airplane.