Hydraulics Flashcards
A. The airplane has three independent hydraulic systems to provide power for:
Spoilers Nose wheel steering Landing gear Wheel brakes Thrust reverser Flight controls
hydraulic fluid ____ be transferred from one system to another. All three systems use skydrol hydraulic fluid and operate at a nominal pressure of ____
psig
cannot
3000 psig
POWER TRANSFER UNIT (PTU) CONTROL KNOB (ROTARY ACTION)
OFF:
AUTO:
ON:
OFF: turns the PTU off.
AUTO: allows the PTU to operate automatically, according to hydraulic system logic.
ON: operates the PTU continuously, overriding the hydraulic system logic.
SYS 1 AND SYS 2 ENGINE PUMP SHUTOFF VALVE BUTTONS
(GUARDED)
Pushbuttons:
Pushbuttons:
Closes the hydraulic shutoff valve (SOV), isolating the respective engine driven pump (EDP) from the associated hydraulic system
SYS 1 AND SYS 2 ELECTRIC HYDRAULIC PUMP SELECTOR KNOBS
(ROTARY ACTION)
OFF:
AUTO:
ON:
OFF: turns the associated electrical pump off.
AUTO: allows the associated electrical pump to operate
automatically, according to hydraulic system logic.
ON: operates the associated electrical pump continuously, overriding the system logic.
SYS 3 ELECTRIC HYDRAULIC PUMP B SELECTOR KNOB (ROTARY
ACTION)
OFF:
AUTO:
ON:
OFF: turns the electrical pump off.
AUTO: allows the electrical pump to operate automatically,
according to hydraulic system logic.
ON: operates the electrical pump continuously, overriding
the system logic.
SYS 3 ELECTRIC HYDRAULIC PUMP A SELECTOR KNOB (ROTARY
ACTION)
OFF:
ON:
OFF: turns the electrical pump off.
ON: turns the electrical pump on.
Hydraulic System 1 is comprised of
one reservoir,
one Engine-Driven Pump (EDP 1),
one electric hydraulic pump and
two accumulators.
Hydraulic System 1 supplies
the following systems:
Rudder (upper actuator)
Elevator (left hand outboard actuators)
Thrust reverser (engine 1)
Multi-function spoilers (left and right panels 3 and 4)
Ground spoilers (left and right panel 2)
Outboard brake
Emergency parking brake
The hydraulic systems 1 and 2 are equipped with an overheating protection system. When the hydraulic fluid temperature increases to ___°C, the HYD 1/2 HI
TEMP EICAS caution message will be displayed.
If the fluid temperature reaches ___°C, the shutoff valve (SOV) will automatically actuate, thus isolating the EDP 1/2 from the respective hydraulic flow line.
In the event of hydraulic system overheat (fluid temperature above ___°C), the HYD 1/2 OVERHEAT EICAS warning message will be displayed. In this
case, the SOV can be manually commanded through a guarded pushbutton on the hydraulic system control panel.
100°C,
125°C,
145°C.
The EDP 1/2 is connected to the engine 1/2 ______ and it is the _____ for Hydraulic System 1/2. Its normal operation requires no pilot action.
accessories gearbox
primary power source
The Electric Hydraulic Pump 1 (ACMP 1B) is an alternating current motor pump. It serves as a ____for the EDP 1 and it is powered by the _____
The Electric Hydraulic Pump 2 (ACMP 2B) is an alternating current motor pump. It is used as a ____for the engine driven pump (EDP 2) and it is powered by the_____
backup
AC BUS 2.
backup
AC BUS 1.
In FLIGHT, with the selector knob set to AUTO position, the Hydraulic System logic activates the electric pump in case of:
(a) ______, or
(b) ______.
(a) EDP or engine fail, or
(b) Flaps selected to any position greater than 0°.
On GROUND, with the selector knob set to AUTO position, the Hydraulic System logic activates the electric pump in case of:
Flaps selected to any position greater than 0° and:
(a) Thrust levers set to takeoff thrust, or
(b) Ground speed greater than 50 kt
Also, during takeoff when thrust levers are set to TOGA, the Electric Hydraulic Pumps will be activated for ___s to avoid abrupt hydraulic pressure variations in an event of engine failure.
60 s
Hydraulic System 1 Accumulator
A pressure accumulator is designed to maintain a constant pressure during periods of transient flow demands in the operation of the Hydraulic System. The accumulator also keeps a residual pressure in the hydraulic reservoir in order to avoid pump cavitations
HYDRAULIC SYSTEM 2
A. Hydraulic System 2 is comprised of
HYDRAULIC SYSTEM 2
one reservoir,
one engine-driven pump (EDP 2),
one electric hydraulic pump,
two accumulators and
one PTU.
The Hydraulic
System 2 supplies the following systems:
(1) Elevator (left and right hand inboard actuators)
(2) Ailerons (right and left inboard actuators)
(3) Thrust reverser (engine 2)
(4) Multi-function spoilers (left and right panels 5)
(5) Ground spoilers (left and right panel 1)
(6) Inboard brake
(7) Nose wheel steering
(8) Landing gear (retraction and extension)
(9) Emergency parking brake
The operation of the Electric Hydraulic Pump 2 is similar to Electric Hydraulic Pump 1.
Also, on ground, the Electric Hydraulic Pump 2 will be automatically activated (for nosewheel steering and inboard brakes) when the following conditions occur:
(a) Engine 1 running and parking brake released;
(b) During Engine 1 start (once N2 reaches 40%) if parking brake has been applied within the last 6 min.
NOTE The Electric Hydraulic Pump 2 will be automatically turned off after 6 min have elapsed from parking brake application
Power Transfer Unit (PTU)
The PTU consists of a _____ driven by a ____.
The PTU assists the ______
hydraulic pump in Hydraulic System 2
hydraulic motor installed in Hydraulic System 1.
landing gear retraction or extension, should a right engine or right EDP failure occur.
During takeoff and landing, with the selector knob in the AUTO position the hydraulic system logic activates the PTU _____
The PTU will be automatically started when all the following conditions are met:
if the engine 2 or
EDP 2 fails.
Flaps not set to zero or Landing Gear not up and locked;
EDP 1 not fail;
Hydraulic reservoir 2 quantity above 12%
Hydraulic System 3 is comprised of
one reservoir,
two electric hydraulic pumps and
one accumulator.
The Hydraulic System 3 supplies the following systems:
(1) Elevator (right hand outboard actuators);
(2) Rudder (lower actuator);
(3) Ailerons (left and right outboard actuators).
The Hydraulic System 3 is also equipped with an overheat protection
system.
(2) When the hydraulic fluid temperature reaches ____°C, the HYD 3 HI TEMP EICAS caution message will be displayed.
(3) If the fluid temperature increases up to ____°C, both Electric Hydraulic
Pumps (3A and 3B) will automatically be turned OFF
In the event of hydraulic system overheating (fluid temperature above
___°C), the HYD 3 OVERHEAT EICAS warning message will be displayed.
In this case, the flight crew can manually switch OFF pumps 3A and 3B on
the hydraulic system control panel.
100
125
145
Electric Hydraulic Pump 3A (ACMP 3A) is the ____power
source for Hydraulic System 3 and it is powered by the ____
primary
AC ESS BUS.
The Hydraulic System 3 accumulator is similar to the Hydraulic System 1 and 2 accumulators, except for its operation during an electrical emergency. In this condition, the Hydraulic System 3 accumulator
will provide hydraulic power to the
associated flight controls from the beginning of RAT deployment until the ACMP
3A is powered by the AC ESS BUS.
Hydraulic system 3 has two dedicated valves which are used only in an electrical emergency to avoid overload in the RAT
The pump unloader valve is used to reduce the discharge pressure of ACMP 3A during its start-up. This will reduce the pump torque and therefore reduce the electrical power required to start the pump.
The flow limiter valve is used to reduce the amount of flow (1.75 to 2 gallons) provided by the ACMP 3A. This will limit the electrical power that the pump can draw and prevent the electric hydraulic pump from stalling the RAT
When an engine flameout occurs, what happens to the hydraulic EDP of that respective engine?
Depressurizes EDP to facilitate WML start
