Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to all Boeing Model 757 series airplanes, that would have required the replacement of certain discrepant ram air turbine (RAT) deployment actuator assemblies that were shipped improperly. That proposal was prompted by reports of certain RAT actuators that failed to deploy upon command due to interference in the actuator locking mechanism caused by damage incurred during shipping of the actuators. This new action revises the proposed rule to require the use of an FAA-approved maintenance program in lieu of the use of shipping procedures prescribed in that proposal. Failure of the RAT to deploy, specifically during a dual engine failure, would result in loss of hydraulic power and would adversely affect the continued safe flight and landing of the airplane.