"This SAE Aerospace Standard (AS) specifies the general requirements for hydraulic system reservoirs that are installed in commercial and military aircraft and helicopters and also in missile hydraulic systems. This document includes design@ test (production and qualification) criteria for various types of reservoirs. Appendix A provides information on hydraulic fluid volume requirements and reservoir sizing. This document also provides a basis for the Procurement Specification to completely define individual reservoir requirements Reservoir Types: Type A - Separated@ hydraulically pressurized - (commonly referred to as a ""bootstrap reservoir"") Type B - Separated@ gas pressurized - (commonly through an engine bleed system or by a pressurized gas charge) Type C - Separated@ mechanically pressurized - (usually by a spring and for emergency use) Type D - Non-separated@ gas pressurized - (commonly through an engine bleed system) Type E - Non-separated@ non-pressurized - (commonly referred to as an open reservoir)"