This Aerospace Specification establishes the requirements for a threaded flexible coupling assembly, hereafter referred to as the assembly, which utilizes ferrules or machined tube end fittings to join tubing and components in aircraft fuel, vent, or other systems. This coupling assembly is designed for use from −54 to 93 °C and at 862 kPa peak working pressure. AS coupling components referenced herein have been qualified to AS1710. Ferrule referenced herein are inch ferrules adapted to metric tubing.