Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to all Boeing Model 737-100 and -200 series airplanes, that would have required replacement of certain outboard and inboard wheel halves with improved wheel halves. That action also would have required cleaning and inspecting certain outboard and inboard wheel halves for corrosion, missing paint in large areas, and cracks; and repair or replacement of the wheel halves with serviceable wheel halves, if necessary. That proposal was prompted by a review of the design of the flight control systems on Model 737 series airplanes. This action revises the proposed rule by extending the compliance time, revising the applicability of the AD, and clarifying part and serial numbers of affected wheel assemblies and halves. The actions specified by this proposed AD are intended to prevent failure of the wheel flanges, which could result in damage to the hydraulics systems, jammed flight controls, loss of electrical power, or other combinations of failures; and consequent reduced controllability of the airplane.