This specification defines the requirements for a threaded rigid coupling assembly@ which utilizes ferrule type machined tube end fittings@ to join tubing and components in aircraft fuel@ vent@ and other systems. This coupling assembly is designed for use from -65 to 200 ??and at 125 psig operating pressure. Classification The coupling assemblies shall be of the following types: Type I: without wrenching lugs Type II: with wrenching lugs