from any service pump in either pump room to any service station on the flight or hangar decks. Service station risers extend upward from the out- board distribution main to supply the service stations on the hangar and flight decks. At the service station, the supply riser branches off to each hose reel. Isolation valves are installed at strategic points throughout the outboard distribution piping. These valves are normally in the open position during at-sea operations, but are closed to isolate specific sections in an emergency or if damage occurs. They are lo- cated in both the outboard distribution main and the service station risers. Jet Test System This system provides JP-5 to the Jet Engine Test Facility located on the fantail of aircraft carriers. The system has its own pump and filter/separator. Supply to this system is from the JP-5 service-pump suction header. The system has a return line from the test stand to permit operation of jet engines at various flow rates. Auxiliary JP-5 System This system provides JP-5 to emergency diesel generators, auxiliary boilers, small-boat filling sta- tions, or combat vehicle/support equipment filling station. It is an independent system and typically con- sists of an auxiliary pump, an auxiliary main and branches supplying each station. This system is also supplied from the JP-5 service-pump suction header. JP-5 FUELING SYSTEM COMPONENTS LEARNING OBJECTIVE: Identify the various components that make up the JP-5 below decks fueling system. Describe their function, princi- ples of operation, and operating limits. In the first section of this chapter, we talked about JP-5 fueling subsystems. We discussed their typical arrangements and where pumps, filters, cutout valves, purifiers, and other components would fit in that sys- tem. And as was stated earlier, though all JP-5 fueling system arrangements are alike the actual makeup of each system will be different. In this section, we identify and describe specific components of the JP-5 fueling system. We cover their description, operating capacities, some trou- bleshooting and maintenance, and where they would typically fit in a subsystem. Remember, your individ- ual systems may vary. PUMPS A pump is a machine that draws a fluid into itself through a suction port and forces the fluid out through a discharge port. The ABF uses pumps in the JP-5 below decks system to move JP-5 from tank to tank, and to lift JP-5 to the flight and hangar deck refueling stations. Wear occurs in a pump as in any other piece of machinery. To maintain a pump at or near the effi- ciency it had when new and to keep maintenance at a minimum periodic tests should be made to determine the delivery capacity of the pump. When a test indi- cates a noticeable reduction in the delivery capacity, it is a sign of possible internal wear. The pump should be opened for inspection in accordance with PMS. If corrective action is not immediately taken total fail- ure of the wearing parts may result in excessive repair costs as well as considerable down time of the pump. Always follow the manufacturer’s instructions in the applicable technical manuals. The various type pumps and their functions are discussed here. Centrifugal Due to their simplicity and adaptability to a wide variety of operating conditions, centrifugal pumps are widely used. They can be modified to operate over a wide range of heads, can handle liquids at all normal temperatures, and operate at speeds that are standard for motors or turbines. The characteristics of these pumps are such that liquid flow from them is continu- ous, and their discharge can be throttled without building up excessive pressures in the pumps or over- loading the driving unit. The most common manufacturers of the centrifu- gal pumps used in the JP-5 below decks system are Aurora and Carver. The Aurora is the pump discussed here. But, there are other pumps installed and you should always consult the technical manual for details on the specific pump in your system. The primary use of centrifugal pumps in the JP-5 below decks system are as service pumps. The Aurora JP-5 Service Pump is a double-suction, single-stage, centrifugal pump. The pump is designed to deliver fuel at 1,100 gallons per minute at 150 psi with a 4-10