The ELEC 2 (system A) or ELEC 1 (system B) pump ON/OFF switch controls the related electric motor–driven pump. If an overheat is detected in either system, the related OVERHEAT light illuminates.
System A Hydraulic Leak - If a leak develops in the engine–driven pump or its related lines, a standpipe in the reservoir prevents a total system fluid loss. With fluid level at the top of the standpipe, the reservoir quantity displayed indicates approximately _____
System A hydraulic pressure is maintained by the electric motor–driven pump.
System A Hydraulic Leak - If a leak develops in the electric motor–driven pump or its related lines, or components common to both the engine and electric motor–driven pumps:
If one FLIGHT CONTROL switch is moved to STBY RUD:
Standby Hydraulic System Leak - System B continues to operate normally, however, the system B reservoir fluid level indication decreases and stabilizes at:
Loss of an engine-driven hydraulic pump and a high demand on the system may result in an intermittent illumination of the LOW PRESSURE light for the remaining electric motor-driven hydraulic pump.
The flight control LOW PRESSURE light, Master Caution light, and the FLT CONT and HYD system annunciator lights also illuminate.
STBY RUD ON Light - When illuminated amber, it indicates the standby hydraulic system is commanded on to pressurize the standby rudder power control unit.
Landing Gear Transfer Unit - The system B engine–driven pump supplies the volume of hydraulic fluid needed to operate the landing gear transfer unit when all of the following conditions exist:
STANDBY HYDRAULIC LOW PRESSURE Light - When illuminated amber:
The amber LOW pressure light for the No.1 Engine Driven Hydraulic Pump illuminates. What should you do?
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System A Hydraulic Leak - If a leak develops in the engine–driven pump or its related lines, a standpipe in the reservoir prevents a total system fluid loss. With fluid level at the top of the standpipe, the reservoir quantity displayed indicates approximately _____
System A hydraulic pressure is maintained by the electric motor–driven pump.
Electric Hydraulic Pump OVERHEAT Lights - What does this light indicate?
Power Transfer Unit (PTU) - The purpose of the PTU is to supply the additional volume of hydraulic fluid needed to operate _____ when system B engine–driven hydraulic pump volume is lost.
If the hydraulic system is not properly pressurized, foaming can occur at higher altitudes. Foaming can be recognized by:
In case of loss of system A:
Both A and B hydraulic systems have an engine–driven pump and an AC electric motor–driven pump. The system A engine–driven pump is powered by the No. 2 engine and the system B engine–driven pump is powered by the No. 1 engine.
The system A engine–driven pump is powered by the No. 1 engine and the system B engine–driven pump is powered by the No. 2 engine.
Loss of an engine-driven hydraulic pump and a high demand on the system may result in an intermittent illumination of the LOW PRESSURE light for the remaining electric motor-driven hydraulic pump.
Standby Hydraulic System - The standby hydraulic system is provided as a backup if system A and/or B pressure is lost. The standby system can be only activated automatically.
The standby system can be activated manually or automatically.
An engine–driven hydraulic pump supplies approximately _____ the fluid volume of the related electric motor–driven hydraulic pump.
Variations in Hydraulic Quantity Indications - During normal operations, variations in hydraulic quantity indications occur when:
These variations have little effect on systems operation.
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ALTERNATE FLAPS Master Switch - When placed in the ARM position, the ALTERNATE FLAPS Master switch:
Standby Hydraulic System Leak - The LOW QUANTITY light illuminates when the standby reservoir:
The RFF indication is displayed:
With the loss of hydraulic system B and with the system A operating normally:
Minimum fuel for ground operation of electric motor-driven pumps is _____ in the related main tank.
Hydraulic fluid used for cooling and lubrication of the pumps passes through a heat exchanger before returning to the reservoir. The heat exchanger for system A is located in main fuel tank No. 2 and for system B is in main fuel tank No. 1.
The heat exchanger for system A is located in main fuel tank No. 1 and for system B is in main fuel tank No. 2.
Power Transfer Unit (PTU) - The PTU uses system B pressure to power a hydraulic motor–driven pump, which pressurizes system A hydraulic fluid.
Standby Hydraulic System Leak - If a leak occurs in the standby system, the standby reservoir quantity decreases to _____
The standby hydraulic system uses a single electric motor–driven pump to power:
In addition to hydraulic system A and B, the rudder can also be powered by the standby hydraulic system through the:
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STANDBY HYDRAULIC LOW QUANTITY Light - What is the true statement?
System B Hydraulic Leak - A leak in system B can significantly affect the operation of the standby hydraulic system.
A leak in system B does not affect the operation of the standby hydraulic system.