Electric Trim Systems: Design and Certification Considerations under FAR 23.677 (CAM 3.337-2)

The FAA uses the Federal Aviation Regulations (FARs) as the criteria for the approval and certification of all aircraft and appliance designs. In addition to assuring that systems will perform their intended function, the FARs attempt to maximize safety and utility. Recent changes in the official interpretation of the Regulations have caused changes in the performance and certification procedures of electric trim systems. An understanding of these changes is essential for anyone working in the design and/or certification of these systems.