an improved single engine military aircraft is provided through the use of an improved secondary power system which incorporates an additional accessory drive , and utilizes improved multi - path system architecture together with optimal distribution of accessories to thereby enhance partial operational flexibility of the secondary power system in both normal and partial failure modes of operation . the additional accessory drive also provides an aircraft in which the engine can be removed with minimal disruption of the emad or amad and accessories mounted thereon to thereby enhance both initial manufacturability and repairability of the aircraft and secondary power system .