Refer to the refill indication (RF) to the Right of the hydraulic system quantity indication. Indication is displayed:
When hydraulic quantity is below 76% in either system A and/or B and the airplane is on the ground with both engines shutdown or after landing with flaps up during taxi-in.
If a leak develops in either pump, line or component of system B, the quantity decreases until it indicates approximately zero and system B pressure is lost. The system B reservoir has one standpipe which supplies fluid to both the engine–driven pump and the electric motor–driven pump. However, with fluid level at the top of the standpipe, fluid remaining in the system B reservoir is sufficient for power transfer unit operation.
True.
If a leak occurs in the Standby Hydraulic System, the standby reservoir quantity decreases to zero. What is the effect on System B reservoir quantity?
Decreases to approximately 72% full.
Either A or B hydraulic system can power all flight controls with no decrease in airplane controllability.
True.
The Power Transfer Unit (PTU) provides a backup source of hydraulic pressure to operate the:
Autoslats and leading edge flaps and slats.
The purpose of the PTU is to supply the additional volume of hydraulic fluid needed to operate the autoslats and leading edge flaps and slats at the normal rate when system A engine-driven hydraulic pump volume is lost. The PTU uses system B pressure to power a hydraulic motor-driven pump, which pressurizes system A hydraulic fluid.
False.
The autoslat system:
Is normally powered by Hydraulic System B.
Pulling the No.2 engine fire warning switch shuts off hydraulic fluid to the:
Engine driven pump in System B.
The standby hydraulic system powers the:
Leading edge devices, rudder, thrust reversers, and standby yaw damper.
What is one indication of a leak in the standby hydraulic system?
The LOW QUANTITY light illuminates.
The amber standby hydraulic system LOW PRESSURE light is armed:
Only when standby pump operation has been selected or automatic standby function is activated.
Which of the following actions will affect hydraulic quantity indications?
Landing gear is extended & Leading edge devices are extended.
The amber LOW PRESSURE lights for the No.1 Engine Driven Hydraulic Pump illuminates. What should you do?
Position the hydraulic pump switch to off.
What is the minimum fuel quantity limitation in the main fuel tanks for ground operation of the electric hydraulic pumps?
760 kgs (1676 lbs) in the related main tanks.
The Landing Gear Transfer Unit:
Ensures System B can raise the gear on loss of System A.
The illuminated Standby Hydraulic LOW PRESSURE Light indicates output pressure of standby pump is low. It is only armed when:
Standby pump operation has been selected or automatic standby function is activated.
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 ___ full.
20%.
System A & B hydraulic fluid is cooled by:
Heat exchangers located in the main fuel tanks.
A fluid leak develops in System A electric pump or its related lines, or components common to both the engine and electric motor driven pumps, the quantity in the reservoir steadily decreases to zero and all system pressure is lost.
True.
The Power Transfer Unit operates automatically when all of the following conditions exist:
System B engine-driven pump hydraulic pressure drops below limits only when airborne and when flaps are less than 15 but not up.
The purpose of the landing gear transfer unit is to supply the volume of hydraulic fluid needed to raise the landing gear at the normal rate when system B engine-driven pump volume is lost.
False.
The standby hydraulic system is provided as a back-up if system A and/or B pressure is lost. The standby system can be activated manually or automatically and uses a single electric motor-driven pump to power:
Thrust reversers, rudder, leading edge flaps & slats (extend only) and standby yaw damper.
Automatic operation of the Standby Hydraulic System is initiated when all the following conditions exist:
Loss of system A or B, flaps extended and airborne or wheel speed greater than 60 kts and FLT CONTROL switch A or B Hydraulic System ON.
Automatic operation of the Standby Hydraulic System is initiated when:
The main PCU Force Flight Monitor trips.
