This SAE Aerospace Information Report (AIR) provides the hydraulic system designer with the various design options and techniques currently available to enhance the survivability of hydraulic systems. A comprehensive knowledge of the hostile environment to which the air vehicle will be exposed will form the basis upon which the overall design philosophy is formulated. The designer should strive to achieve at the absolute minimum a system which provides the actuation and control capability to meet the minimum acceptable flying quality level to complete the operational mission for which the aircraft is designed; i.e., the aircraft can be controlled and the mission terminated safely, including landing. This AIR will attempt to address the following threats: a Typical Small Arms Fire (5.56, 7.62, 12.7 and 14.5 mm AP) b Cannon (20, 30, and 40 mm API/HEI) c NBC/EMI/EMP/Beamed Particle d Chemical/Biological Protection against missiles is beyond the scope of this AIR.