UFC 3-460-03
21 JANUARY 2003
return venturi DPT senses a flow of 2120 liters per minute (560 gallons per minute) or greater
for more than 60 consecutive seconds, the microprocessor initiates shutdown.
6.6.1.1.7. During shutdown, the solenoid on the BPCV will D/C the valve and cause the
hydrant loop pressure to rise.
6.6.1.1.8. When the loop pressure reaches 175 psi, three things happen:
6.6.1.1.8.1. The microprocessor calls off the lead pump.
6.6.1.1.8.2. Solenoid A on the D/FV will E/E the valve to bleed system pressure to 80 psi.
6.6.1.1.8.3. PCV solenoid will D/E the valve to bleed the pressure to 75 psi.
6.6.1.1.9. Now the system is back to the automatic mode/idle condition.
6.6.1.2. Refueling Condition. To begin an aircraft refueling operation, the operator must use
fueling equipment such as an HSV or R-12, hydrant hose truck (HHT), hose cart, or a pantograph
to connect the HCV and API adapter to the aircraft. The control valve can be either hydraulically
(fuel) or pneumatically (air) operated, depending on the type of fueling equipment and deadman
system. When the operator squeezes the deadman, the HCV begins to open. As system pressure at
PIT 1 or PIT 2 (depending on microprocessor selection) drops below 60 psi, the control system
will cause the following:
6.6.1.2.1. The lead fueling pump will start.
6.6.1.2.2. The BPCV 58AF-9 solenoid will E/E the valve to modulate open at its set point
(typically between 100 and 130 psi at the furthest hydrant outlet).
6.6.1.2.3. The PCV 58AF-3 solenoid will E/C the valve any time a pump is running
6.6.1.2.4. The D/FV 58AF-9-1 solenoid A (defueling) will D/C the valve, and solenoid B
(flush) will D/C any time the system is not in the flush mode.
6.6.1.2.5. The lead fueling pump immediately establishes a flow of 2271 liters per minute
(600 gallons per minute) that is sensed by the issue venturi DPT.
6.6.1.2.6. If the issue venturi DPT senses 2271 liters per minute (600 gallons per minute) (lead
pump running), and the return venturi DPT senses a flow between 151 and 2120 liters per
minute (40 and 560 gallons per minute), the lead pump continues to operate and no other pumps
will start.
6.6.1.2.7. If refueling continues and an additional aircraft begins fueling, the flow through the
return venturi could drop below 151 liters per minute (40 gallons per minute).
6.6.1.2.8. With only the lead pump running (2271 liters per minute [600 gallons per minute]), if
the return venturi DPT senses less than 151 liters per minute (40 gallons per minute) for 10
consecutive seconds, a second pump will be energized.
6.6.1.2.9. With two pumps running (4542 liters per minute [1200 gallons per minute]), if the
return venturi DPT senses less than 151 liters per minute (40 gallons per minute) for 10
consecutive seconds, the microprocessor will call on the third pump.
6.6.1.2.10. With three pumps running (6813 liters per minute [1800 gallons per minute]), if the
return venturi DPT senses less than 151 liters per minute (40 gallons per minute) for 10
consecutive seconds, the microprocessor will call on the fourth pump.
68