This SAE Aerospace Recommended Practice (ARP) is intended as a guide in defining the requirements for aircraft hydraulic self-displacing accumulators, including details pertinent to the design, fabrication, and performance of the accumulator. This type of accumulator has a piston separator and contains a low pressure chamber and a high pressure chamber for actuating a self-displacing piston. For use in aircraft hydraulic systems of the following types as defined in MIL-H-5440 with rated operating pressures to 8000 psi (55,160 kPa). Type I: -65 to +160 °F (-54 to +71 °C) fluid temperature; Type II: -65 to +275 °F (-54 to +135 °C) fluid temperature. For commercial aircraft applications, the information and guidelines of ARP4752 are considered.