Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that would have required modification of the left and right inboard elevator servo assemblies and the hydraulic routing of the right inboard elevator power control package (PCP). That proposal was prompted by a report of an uncommanded right elevator deflection after takeoff and reports of elevator/control column bumps during landing gear retraction on these airplanes. This action revises the proposed rule by revising the applicability of the proposed AD to add additional airplanes and additional part numbers of the elevator PCP's, and by including additional service information. The actions specified by this proposed AD are intended to prevent uncommanded elevator deflection, which could result in structural damage and reduced controllability of the airplane.