Pratt & Whitney designs and manufactures a variety of products for commercial and military aircraft. Products include airborne auxiliary power units and ground power units and, small expendable and recoverable turbojet propulsion systems. Auxiliary Power Units (APUs) are gas turbine engines used primarily during aircraft ground operation to provide electricity, compressed air, and/or shaft power for main engine start, air conditioning, electric power and other aircraft systems. APUs can also provide backup electric power during in-flight operation.
Pratt & Whitney is a major supplier of gas turbine APUs for military applications, including helicopters such as the V-22, CH-53K, UH60/S70 Blackhawk and Chinook, fighters such as the F-16, JAS39 and T-50, and military transports including the C-5, A400M and KC390.