This Aerospace Information Report (AIR) has been written to provide in-service reliability data of continuously active ball screw and geared flight control actuation systems. 

Purpose 

The purpose of this information report is to compile the results of the survey as detailed in the foreword so the data can be made available to the industry as an aid for those specifying, designing, and certifying mechanical actuators, as well as those developing reliability and safety analyses and reports for these actuators. 

NOTE: This reliability data could assist in addressing the failure mode and effect analysis (FMEA) for new electro-mechanical actuators that are based on similar mechanical sub-assemblies by using the equivalent functional (e.g., duty cycle) and environmental conditions. For example, it is especially relevant when the FMEA relates to equipment that is considered as critical like for primary flight control system. 

Field of Application 

This report is written with commercial aircraft flight control system applications in mind, but the data presented is equally applicable to other aircraft systems or other aircraft categories.