This Aerospace Standard (AS) defines the requirements for a heavy braid polytetrafluoroethylene (PTFE) lined, metallic reinforced, hose assembly suitable for use in high temperature, 400 °F, high pressure, 3000 psi, aircraft hydraulic fluid systems, also for use in pneumatic systems which allow some gaseous diffusion through the PTFE wall. The -20 size operating temperature is limited to 275 °F maximum.