Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Boeing Model 767 series airplanes. This proposal would require repetitive operational tests to verify proper deployment of the ram air turbine (RAT), and replacement of the rotary actuator motor with a new or serviceable rotary actuator motor, if necessary. This proposal is prompted by reports of corroded rotary actuator motors of the RAT found on in-service airplanes. The actions specified by the proposed AD are intended to prevent such corrosion, which could result in failure of the RAT to deploy and subsequent loss of emergency hydraulic power to the flight controls in the event that power is lost in both engines.