This SAE Aerospace Recommended Practice (ARP) encompasses design, analysis, fabrication, and installation of pressurized metal tubing used in fluid power systems to provide relative motion.

Specific data given are for MIL-T_6845 tubing ranging from 1/4 to 1 in. (6.3 to 25 mm) to diameter used in 3000 psi (20.7 MPa) hydraulic or pneumatic system, Military Type I, II, III, or IV hydraulic systems applied to any type of vehicle. For information on design of coiled tube assemblies using Ti-3Al-2.5CWSR tubing, see ARP4146.

The flexible configurations of tubing are intended for application to actuators that oscillate about a pivot, to areas of large structural deflection such as reservoirs installation, and to areas of extrement environment where flexible hose could not survive.

The purpose of this document is to proide engineering guidance in designing metal tubing configurations that provide for large relative motion between contiguous points in fluid piping systems.