Airworthiness Directives; Airbus Model A330, A340-200, and A340-300 Series Airplanes

摘要

This document revises an earlier proposed airworthiness directive (AD), applicable to the airplane models listed above. That proposed AD would have superseded an existing AD currently requiring repetitive inspections to detect discrepancies of the transfer tubes and the collar of the ball nut of the trimmable horizontal stabilizer actuator (THSA), and corrective action if necessary. The proposed AD would have expanded the applicability of the existing AD; and required new repetitive inspections for discrepancies of the ball screw assembly; corrective action if necessary; repetitive greasing of the THSA ball nut, and replacement of the THSA if necessary; and a modification or replacement (as applicable) of the ball nut assembly, which would end certain repetitive inspections. This new action revises the proposed AD by clarifying affected part numbers and adding a new compliance time for the inspection of the ball screw assembly which would apply under certain conditions. The actions specified by this new proposed AD are intended to prevent degraded operation of the THSA due to the entrance of water into the ball nut. Degraded operation could lead to reduced controllability of the ai