Hydraulic system B loses Engine-Driven Pump pressure in flight while the trailing-edge flaps are between UP and 15. How can leading-edge flap and slat hydraulic power still be maintained without transferring hydraulic fluid between system A and system B?, Hydraulic system A pressure is routed directly through the Hydraulic Power Transfer Unit into the system B pressure manifold., Hydraulic system A powers the motor side of the Hydraulic Power Transfer Unit, while the pump side draws fluid from the system B reservoir and pressurizes the leading-edge devices., The standby hydraulic reservoir transfers fluid into system B through the fill-and-balance line while system A powers the leading-edge devices., The Engine-Driven Pump switch is selected OFF while the associated engine continues to operate. Which condition most accurately describes the Engine-Driven Pump?, The pump continues rotating and retains case-drain lubrication and cooling, but its depressurization solenoid moves the pump to essentially zero system-output flow., The pump supply shutoff valve closes, stopping reservoir supply and case-drain flow while the pump continues rotating., Electrical power removes the pump mechanically from the accessory gearbox until the switch is returned to ON., Why does hydraulic system A retain approximately 2.3 gallons of fluid below the Engine-Driven Pump standpipe, whereas hydraulic system B retains approximately 1.3 gallons below its standpipe?, System A reserves fluid for its Electric Motor-Driven Pump, while system B reserves fluid below the standpipe specifically for the Hydraulic Power Transfer Unit pump., System A reserves fluid exclusively for alternate brakes, while system B reserves fluid for the standby hydraulic reservoir., System A requires the larger reserve because both of its pumps draw through the lower reservoir port, whereas only the system B Engine-Driven Pump uses a standpipe., A system B Engine-Driven Pump pressure loss is being investigated, but user-system pressure remains normal because the Electric Motor-Driven Pump is operating. Why can the Engine-Driven Pump LOW PRESSURE indication be delayed?, The pressure module intentionally inhibits the Engine-Driven Pump LOW PRESSURE light whenever the Electric Motor-Driven Pump is producing normal system pressure., The Display Processing Computer averages the output pressure of both pumps before allowing a LOW PRESSURE warning., Pressure trapped in the line between the Engine-Driven Pump and pressure module can delay the pressure-switch response for two minutes or more., A main hydraulic return filter becomes progressively contaminated. What sequence occurs as differential pressure increases?, At approximately 65 pounds per square inch differential the red indicator extends, and at approximately 100 pounds per square inch the bypass valve opens to permit return flow around the filter., At approximately 65 pounds per square inch the bypass valve opens, and at 100 pounds per square inch the red indicator extends., The return filter has no bypass; at approximately 100 pounds per square inch the hydraulic system pressure-relief valve opens instead., During automatic standby-rudder activation, which combination is sufficient to energize the automatic standby relay under the normal low-flight-control-pressure logic?, Either Flight Control switch ON, trailing-edge flaps not UP, aircraft airborne or wheel speed above 60 knots, and flight-control system A or B pressure below 1,300 pounds per square inch., Both Flight Control switches ON, trailing-edge flaps greater than 15, aircraft airborne, and both flight-control systems below 1,600 pounds per square inch., Either Flight Control switch in STANDBY RUD, flaps UP, wheel speed above 60 knots, and standby pump pressure below 1,300 pounds per square inch., The ALTERNATE FLAPS arm switch is selected ARM and the ALTERNATE FLAPS control switch is momentarily moved to DOWN. Why does Hydraulic Power Transfer Unit operation stop?, The standby Electric Motor-Driven Pump raises system B Engine-Driven Pump pressure above 2,350 pounds per square inch, automatically cancelling the Hydraulic Power Transfer Unit command., The alternate-flap switch removes system A pressure from the Hydraulic Power Transfer Unit motor by closing the system A pressure-module check valve., The leading-edge standby-drive shutoff-valve relay energizes and, through the standby shutoff-valve indication relay, commands the Hydraulic Power Transfer Unit control valve closed., The system B Engine-Driven Pump pressure briefly falls below 2,350 pounds per square inch and then recovers while the aircraft remains airborne with the trailing-edge flaps not UP. Why may the Hydraulic Power Transfer Unit continue operating?, The Hydraulic System B Engine-Driven Pump relay contains a holding circuit that maintains the command after the initial low-pressure input and prevents repeated cycling around the pressure threshold., The Hydraulic Power Transfer Unit control valve mechanically latches open until the aircraft returns to the ground., The system B pressure switch remains electrically latched until system pressure exceeds 3,500 pounds per square inch., A hydraulic system reservoir quantity decreases below 76 percent during flight with both engines operating and the trailing-edge flaps extended. Why might the RF refill message not appear despite the low indicated quantity?, The quantity transmitter does not send values below 76 percent while system pressure remains above 1,600 pounds per square inch., The refill message is inhibited in flight and is only permitted on the ground when the specified flap or engine conditions are satisfied., The refill message is generated only when reservoir quantity falls below 21 percent., An aircraft equipped with a Vickers Electric Motor-Driven Pump experiences excessive internal pump temperature. How does its protective response differ from the Parker Electric Motor-Driven Pump installation?, The Vickers pump continues operating and only illuminates the OVERHEAT light, whereas the Parker pump automatically shuts down., The Vickers temperature switch removes electrical power from the pump, producing a LOW PRESSURE indication rather than directly illuminating the pump OVERHEAT light., The Vickers pump automatically transfers electrical supply to the opposite hydraulic system before shutting down.

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