DC Electric Motor Redesign

Since the beginning of C-5 service, the C-5 community was plagued by a mean time between failure (MTBF) problem with the emergency gear extension motor. The problem was significant. About 75% of these motors failed at Programmed Depot Maintenance (PDM) due to environmental intrusions and other factors. The potential for failure put the aircraft at risk if a landing gear emergency occurred.

The C-5 Emergency Gear Actuation Motor was United Dynamics’ ground-up design to solve this problem.

Our mechanical and electrical engineers worked closely with the Air Force cognizant engineers and the C-5 SPO office to design and develop a new motor that would increase the MTBF by order of magnitude. The design required careful analysis of the mechanical and electrical requirements in order to match and surpass the performance of the existing motor.

Full up qualification and flight test proved our design approach, assembly and manufacturing techniques. The success of the program can be measured by the U.S. Air Force’s decision to retrofit the entire fleet with our new motor rather than change by attrition.