Gulfstream G550 User manual

HYDRAULICS
2A-29-10: General
1. Description:
The G550 aircraft has two hydraulic systems, left and right, each powered by an
engine driven pump installed on the respective left and right engine that
pressurizes fluid contained in dedicated reservoirs. The engine-driven pumps are
not equipped with off / on switches, but continuously operate unless the
respective engine is shut down with the cockpit fire handle. Both systems are
independent, each with separate lines and no common point for fluid interchange
to preserve the integrity of each system. However, since the failure of an engine-
driven pump or the engine itself would result in the loss of the autonomous
hydraulic system, replacement power sources are available. An overview of the
two hydraulic systems is shown in Figure 1.
Hydraulically powered aircraft components, except the engine thrust reversers,
are redundantly protected with either an alternate hydraulic power source, dual
(left and right) hydraulic actuators, hydraulic accumulator pressure or compressed
nitrogen (N
2
) bottle pressure. Control surfaces used throughout the flight regime
are powered using actuators connected to both hydraulic systems, with either
system capable of independently powering the controls. See the following table.
LEFT HYDRAULIC
SYSTEM POWER FLIGHT CONTROL SURFACE RIGHT HYDRAULIC SYSTEM POWER
X Elevator X
X Aileron X
X Rudder / Yaw Damper * X
X Flight Spoilers X
X Speedbrakes X
X Stick Pusher X
*Because the rudder is essential to the control of the aircraft when operating with
only one engine, the rudder and yaw damper is also be powered by an Auxiliary
electric pump using left system fluid. See the following text and table.
Control surfaces and aircraft sub-systems used in the takeoff and landing phases
of flight are subject to many cycles, higher force loads, and a require a greater
range of movement. For design simplicity they are powered by a single system,
the left hydraulic system. However, these components are protected with a high
level of redundancy. The left hydraulic system is unique in that left system fluid
may be pressurized by two sources other than the engine driven pump. An
electrically driven Auxiliary (AUX) pump, or an impeller driven by right hydraulic
system pressure, termed the Power Transfer Unit (PTU) can pressurize left
system hydraulic fluid. These two surrogate hydraulic pressurization sources offer
additional redundancy by using separate quantities of left system hydraulic fluid.
The PTU pressurizes normal left system fluid, but the AUX pump uses a
dedicated quantity of left system fluid preserved within the left system reservoir in
the event of left system fluid loss. If all left and AUX hydraulic fluid is lost, the
components essential to landing can be operated using pressure stored in
accumulators or nitrogen bottles. The following table illustrates the actuation
power sources for takeoff and landing controls, subsystems and actuators:
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Control,
Subsystem or
Actuator
Primary Actuation
Source Secondary Actuation Source Emergency Actuation Source
Landing Gear Left Hydraulic
System Engine
Pump
PTU* Pressurized
Nitrogen Bottle
Brakes Left Hydraulic
System Engine
Pump
AUX hydraulic
pump or PTU Hydraulic Accumulator
Nose Wheel
Steering Left Hydraulic System Engine
Pump
AUX hydraulic
pump or PTU None
Flaps Left Hydraulic
System Engine
Pump
AUX hydraulic
pump or PTU None
Ground Spoilers Left and Right
Hydraulic System
Engine Pumps (left
system pressure
required)
AUX hydraulic
pump or PTU None
*AUX pump pressure is not used as an alternate method of gear extension because
the landing gear actuators require one (1) gallon of fluid to operate. The left reservoir
preserves only two (2) gallons for Aux pump pressurization, so sufficient fluid would
not be available for other components if the landing gear were operated using Aux
pump pressure and fluid.
Left and right systems use Type IV phosphate ester-based hydraulic fluid (Hy-Jet
IV, Skydrol LD-4, etc.) that has an operational temperature range from -40°C to
+255°C. An external service panel mounted on the underside of the tail of the
aircraft has provisions for servicing the reservoirs of both hydraulic systems as
well as connections for attaching pressurized lines and system drain lines. The
panel and specific servicing instructions are shown in Section 09-02-00.
Each hydraulic system is described in the following sections:
•2A-29-20: Left Hydraulic System
•2A-29-30: Right Hydraulic System
2. Limitations:
Approved Hydraulic Fluid Types:
The following fire-resistant Type 4 hydraulic fluids are approved for use:
•HyJet IV
•HyJeT IV-A
•Skydrol LD-4
•Skydrol 500B-4
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Component Hydraulic
Power Sources
Figure 1
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2A-29-20: Left Hydraulic System
1. General Description:
The left hydraulic system supplies fluid drawn from a reservoir and pressurized by
an engine-driven pump to all aircraft components and subsystems that require the
additional force of hydraulic pressure for normal operation. Since left hydraulic
system pressure is the only actuating force for some aircraft components and
subsystems, two additional means of pressurizing the left system are incorporated
to compensate for the loss of the left engine or pump: an electric Auxiliary (AUX)
pump and an impeller driven by right system pressure termed the Power Transfer
Unit (PTU). The AUX pump is provided with a dedicated volume of hydraulic fluid
in the left system reservoir to ensure that AUX pump pressure is available if left
system fluid is lost. See the left hydraulic system diagram in Figure 2 and the
component locations shown in Figure 3.
In addition to supplying pressurized hydraulic fluid to aircraft actuators, the left
system can be used to power an electrical generator if normal engine and APU
generators are not available. The Standby Electrical Power System Hydraulic
Motor Generator (HMG) is a variable piston hydraulic motor that uses left system
pressure to rotate a generator shaft at eight thousand (8,000) rpm to produce
Alternating Current (AC). For more information regarding the Standby Electrical
Power System HMG, see section 2A-24-00.
The elements that make up the left hydraulic system are:
•Engine-driven Hydraulic Pump
•Fluid Distribution Components
•Reservoir, Fluid Replenishing, and Quantity Gage
•Electric Auxiliary (AUX) Pump
•Power Transfer Unit (PTU)
•Standby Electrical Power System Hydraulic Motor Generator (HMG)
•System Displays
2. Description of Subsystems, Units and Components:
A. Engine-Driven Hydraulic Pump:
The engine-driven hydraulic pump is mounted on the engine accessory
gear box within the nacelle. Engine rotation is translated by the gear
interface to spin the hydraulic pump so that the pump operates whenever
the engine is running. Hydraulic pump output is three thousand pounds per
square inch (3,000 psi) at flow rates between eighteen gallons per minute
(18 gpm) at engine idle and twenty-eight gallons per minute (28 gpm) at
maximum engine thrust. When the engine and pump begin to turn, suction
is generated in the supply line to the pump. The supply line connects the
pump to the left hydraulic reservoir located within the aft equipment bay of
the aircraft.
There is no switch to disable the hydraulic pump; instead, a shutoff valve,
located in the aft equipment bay, is installed in the supply line between the
reservoir and the pump. The shutoff valve is powered by twenty-eight volt
direct current (28v DC) from the left essential bus, and controlled by the left
engine fire handle on the forward section of the cockpit center console.
Pulling out the fire handle closes the shutoff valve, preventing hydraulic
fluid from entering the engine nacelle. The shutoff valve may be physically
opened or closed by positioning a pointer / handle on the valve body in the
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equipment bay.
If the engine the engine fails but is not shut down with the fire handle, the
windmilling engine will continue to turn the hydraulic pump. An airspeed
sufficient to achieve approximately twenty-five to thirty percent (25-30%)
High Pressure (HP) turbine rpm will provide sufficient hydraulic pressure to
operate the flight controls.
B. Fluid Distribution Components:
The hydraulic system is a distributed system rather than a serial system -
i.e., although pressurized fluid does flow through the system, fluid remains
in the system lines after the engine is shut down. When the engine is
started and the engine-driven pump pressurizes the fluid in the lines, the
pressure is effective almost immediately at all points in the system. The
following description is for illustrative purposes, and uses a sequential
format rather than the immediate pressurization of components.
Engine pump fluid first is routed through an acoustic filter that curtails noise
in the hydraulic lines caused by pressure fluctuations when hydraulically
powered aircraft components are activated, then enters a supply line to the
thrust reversers at the aft end of the engine prior to exiting the engine
nacelle.
After leaving the nacelle, hydraulic lines route fluid to the aft equipment bay
to pressurize a system accumulator and then enter a filter manifold in the
equipment bay. The manifold contains a pressurized fluid filter, a fluid
return filter, an AUX pump return filter and an engine and PTU case drain
return filter. Locating all filters within a common manifold allows access to
the replaceable elements of the filters without draining system hydraulic
fluid. The filter manifold also contains a pressure switch and a pressure
transmitter. The pressure switch is used to monitor pump operation and
signal automatic activation of the AUX pump (when the AUX pump is
armed) if system pressure drops below fifteen hundred (1,500) psi. System
fluid passes through the pressure filter, pressure switch and transmitter,
then exits the manifold.
From the filtration manifold in the aft equipment bay, fluid enter lines
supplying aircraft components and subsystems. Lines run aft to supply the
elevators, stick pusher and rudder / yaw damper, and forward to the
ailerons, spoilers, speedbrakes, flaps, landing gear and doors, brakes,
nose wheel steering and main cabin door.
A pressure relief valve in the forward hydraulic supply lines is installed in
the right main wheel well. The pressure relief valve opens if system
pressure exceeds three thousand eight hundred fifty (3,8500) psi. Pressure
is reduced by routing some of the system fluid back to the reservoir through
the return filter in the filtration manifold. When system pressure falls to
three thousand two hundred (3,200) psi, the relief valve closes.
After pressurizing aircraft subsystems and components, system fluid enters
a radiator type heat exchanger located in the right wing fuel tank. The hot
hydraulic fluid is cooled by fuel in the tank (and tank fuel is slightly warmed,
although the high ratio of fuel to hydraulic fluid results in a minimal
temperature rise) then returned to the system reservoir, passing through
the return filter enroute.
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C. Reservoir, Quantity Gage and Fluid Replenishment:
The left system hydraulic reservoir is located on the left side of the aft
equipment bay. The reservoir is a cylindrical container divided internally
into two compartments, one for left system fluid and the other for AUX
pump fluid. Centered within the cylinder is a spool shaped piston that slides
within the reservoir cylinder. Each end of the piston terminates in a plate-
like divider connected with a central shaft. The central shaft penetrates the
internal cylinder wall separating the left and AUX fluid supplies. The larger
plate on the aft end of the shaft defines the volume of the fluid within the
reservoir. When fluid is added to the reservoir, the fluid forces the large
plate of the spool to the end of the reservoir cylinder when the reservoir is
full. The smaller plate at the opposite end of the shaft is surrounded by an
extension of the reservoir cylinder with a smaller cross section. The design
of the reservoir enables system return fluid, ported into the smaller cylinder
extension, to exert a force on the smaller plate end of the central shaft thus
pulling the larger plate against the left and AUX system fluid within the
reservoir. This action, called bootstrap pressure, pressurizes the contents
of the reservoir to approximately thirty to forty (30 - 40) psi., promoting fluid
flow to the engine-driven or AUX pump.
The total capacity of the left hydraulic system, including the fluid in system
lines is twenty point six (20.6) gallons, with the reservoir containing five
point seven (5.7) gallons, of which three point seven (3.7) gallons are
available to the left system and two (2) gallons reserved for use by theAUX
pump. The internal wall separating the two quantities is perforated by a
baffle so that servicing the reservoir fills both compartments of the
container. If left system fluid is depleted by a leak, the large end of the
central spool is pulled toward the wall separating left and AUX fluid, with
the baffle opening in the wall continually admitting left system fluid into the
AUX compartment to ensure the integrity of theAUX fluid supply. If all three
point seven (3.7) gallons of left fluid is lost, the large end of the spool
bottoms out at wall dividing the compartments, preserving the AUX pump
fluid.
The fluid quantity within the reservoir is displayed in two locations:
(1) A direct reading circular gage, mounted on the side of the reservoir,
has a needle pointer and colored bands to indicate quantity. The
gage is illustrated in Figure 4. A green band arcs between the FULL
and REFILL marks and a red band arcs between the REFILL mark
and the EMPTY mark.
(2) An electrically powered float within the reservoir provides quantity
data to the cockpit. The float moves with fluid quantity, with float
displacement measured by a Linear Variable Displacement
Transducer (LVDT). The LVDT is powered by twenty-eight volt direct
current (28v DC) from the left essential bus or the ground service
bus. Quantity information is derived from the displacement
measured by the LVDT, and transmitted electrically to Modular
Avionics Unit (MAU) #1 where it is converted from analog to digital
format and forwarded to the Monitor and Warning System (MWS) for
presentation on cockpit Hydraulics Synoptic, Summary, Secondary
Engine, Engine Start and Ground Service system window displays.
The quantity interface is shown in Figure 5.
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The hydraulic quantity displayed on cockpit synoptic / system
windows is the most accurate reading of fluid in the reservoir. The
cockpit indications are refined to compensate for expansion or
contraction of reservoir fluid caused by temperature variations. A
constant value of twenty-one degrees centigrade (21°C) is used as
an indication standard. The actual temperature within the reservoir
is sampled by a temperature probe that reports data to MAU #1. The
MWS uses the difference between actual reservoir temperature and
the constant assumed temperature (21°C) to add or subtract a
formulated quantity to the amount reported by the LVDT. The
quantity shown on cockpit window displays is thus adjusted to read
as if reservoir temperature remained at 21°C. This adjustment
compensates for the normally indicated loss of fluid as the density of
the hydraulic fluid in the reservoir increases as a result of cold
temperatures during high altitude flight (volume or quantity would
decrease as density increases).
The MWS further refines the quantity indication for the amount of
hydraulic fluid required to retract the landing gear. Approximately
one (1) gallon of fluid is retained within the retract side of the landing
gear actuator when the landing gear is in the up position. The MWS
will add one (1) gallon to the LVDT reported quantity whenever the
landing gear is retracted.
The temperature and landing gear compensatory quantities are
algebraically additive.
(3) The analog quantity signal from the LVDT is shared with a digital
hydraulic quantity gage on the hydraulic fluid replenisher panel. The
panel is located on the right side of the aft equipment bay adjacent
to the reservoirs. The indicator on the panel shows the quantity in
both left and right reservoirs, displayed as horizontal bar graphs.
The bar graphs extend from a refill mark on the left to a full mark on
the right. The indicator has a green band between the full and add
marks on the display, and an amber band to the left of the add mark.
The bar graph is not shown if the quantity in the left reservoir is
below one point eight gallons (1.8 gal), instead the word REFILL is
shown in place of the bar graph. (Right reservoir quantity is not
shown if below one half gallon - 0.5 gal). The panel contains two
switches below the digital display. The switch on the right selects the
indicator ON or OFF. The switch on the left has three positions:
select and test are momentary positions, with the switch returning to
a center neutral position. The down test position initiates a self test
of the display, during which first a checkerboard pattern is shown,
then a reverse checkerboard pattern. Following the patterns, the
indicator bar graphs are displayed with either the left or right
quantity indicated numerically below the bar graphs and the word
OK shown in the right lower corner (assuming quantities are
correctly serviced).
When the left switch is positioned up to the SELECT position, the
numerical indication of quantity will reflect the opposite reservoir
from the one previously shown - i.e. the select position alternates
between left and right reservoirs each time the switch is selected up.
If the quantity within the reservoir drops to refill level, fluid may be added
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using the controls on the replenishing panel in the aft equipment bay
adjacent to the reservoirs, as illustrated in Figure 6. The replenishing panel
has a container that holds up to one and one half gallon (1 ½ gal) of
hydraulic fluid. Below the container on the face of the panel is a pushbutton
switch and a selector lever. Fluid may be transferred from the container to
either reservoir by positioning the selector lever to the left or right reservoir
and depressing the pushbutton. The pushbutton starts an electric pump
that transfers the fluid from the container to the reservoir. The pump is
powered by twenty-eight volt direct current (28v DC) from the ground
service bus. When the hydraulic systems are pressurized, the left system is
considered full at four point eight (4.8) gallons (the right system is full at 1.6
gallons).
D. Electric Auxiliary (AUX) Pump:
The electrically powered Auxiliary (AUX) pump is plumbed into the left
hydraulic system lines in the right main landing gear wheel well. The pump
is powered by the left essential DC bus, and can produce a flow of two (2)
gallons per minute at three thousand (3,000) psi. The pump is cooled by an
integral fan and protected by an overheat switch that shuts off the pump if
pump temperature exceeds 356°F (pump operation will resume when the
temperature falls to 341°F or less). The pump is also protected by an
overload sensor that limits current draw by the pump to two hundred (200)
amperes. The overload shutdown can be reset by selecting the pump off
then back on.
Since the AUX pump is located at some distance from the left system
reservoir, a boost pump is installed in the supply line to theAUX pump. The
boost pump is also powered by essential DC, and is overload protected by
a sensor that will shut off the pump if it draws more than fifteen (15)
amperes. The operation of the boost pump is automatic whenever theAUX
pump is operating. The boost pump comes on whenever the pressure in
the supply line to the AUX pump falls below twenty (20) psi, and the boost
pump shuts off when supply pressure reaches twenty-five (25) psi.
The AUX pump can provide hydraulic pressure to operate the following
components essential to configuring the aircraft for approach and landing if
no other means of pressurizing the left hydraulic system is available:
(1) Rudder and yaw damper
(2) Flaps
(3) Ground spoilers
(4) Brakes
(5) Nose wheel steering
However, the AUX pump cannot power all listed items at the same time. A
valve installed in the AUX pump lines will route pressurized hydraulic fluid
to either the rudder and yaw damper or the other listed components. The
intention is to power the rudder and yaw damper when the aircraft is at
higher airspeeds, when more force would be required to operate flight
controls, then at the lower airspeeds associated with an approach when
control forces are less, make the AUX pressure available to configure the
aircraft for landing.
The AUX pump is also used to close the main cabin door, pressurize the
brake accumulator and operate the landing gear and gear doors for
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maintenance operations. For more information regarding main cabin door
operation, see section 2A-52-00: Doors, and for landing gear and brake
accumulator operation, see section 2A-32-00: Landing Gear.
Operation of the AUX pump is controlled with seven (7) switches. On the
HYDRAULIC CONT panel on the cockpit overhead are two AUX PUMP
pushbutton switches: OFF/ARM and ON (see Figure 7). With the OFF/
ARM pushbutton depressed to the normal ARM position, the AUX pump
will come on whenever left system pressure falls below fifteen hundred
(1,500) psi and a brake pedal is depressed more than ten degrees (10°). If
the OFF/ARM switch is selected to OFF, automatic operation of the AUX
pump is inhibited, and the amber NOT ARM legend in the switch is
illuminated. The ON switch will operate the AUX pump regardless of left
system pressure.
Another pushbutton switch, labelled STBY RUD, located on the lower face
of the instrument panel on the pilot side next to the standby instruments,
will also operate the AUX pump. The switch is depicted in Figure 8.
Depressing the switch will illuminate the amber ON legend in the switch
and open the standby rudder valve to direct AUX pump pressure to the
rudder and yaw damper, provided the aircraft is in the air (weight off
wheels). If using the AUX pump to power system components during
abnormal operations, the standby rudder switch is selected on until
configuring the aircraft for landing. At that time the standby rudder switch is
selected off, and the AUX pump selected on with the switch on the
HYDRAULIC CONT panel. After the aircraft has been configured for
landing, the standby rudder switch is reselected to on, powering the rudder
/ yaw damper until touchdown. When the weight-on-wheels (WOW)
switches compress upon landing, the standby rudder valve will close,
porting AUX pump pressure to the ground spoiler servos, nose wheel
steering and brakes.
Any of the three main cabin door control switches will operate the AUX
pump to close the cabin door, provided the DOOR SAFETY switch on the
cockpit overhead panel is not selected to the ON position. The door control
switches are installed in the following locations:
•On the cockpit overhead
•On the observer and monitor panel
•Within the service panel on the aircraft exterior forward and below
the main cabin door
The AUX pump may also be powered to operate the landing gear and
landing gear doors for maintenance purposes using the ground service
valve installed in the panel on the right side of the aircraft aft of the nose
wheel well. The ground service valve must be held open for theAUX pump
to operate. See the illustration in Figure 9.
E. Power Transfer Unit (PTU):
The Power Transfer Unit (PTU) is a hydraulic motor / pump installation
located in the aft equipment bay on the right side of the aircraft. The motor
side of the installation is driven by the right hydraulic system and controlled
by a shutoff valve. The pump side is plumbed to the left hydraulic system
and connected to the motor side by a common shaft. When the shutoff
valve is open, the right hydraulic system is ported to the motor at twenty-
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eight (28) gallons per minute, turning the pump side at thirty-nine hundred
revolutions per minute (3,900 rpm) producing a flow of twenty-two and one
half (22½) gallons per minute at three thousand (3,000) psi in the left
hydraulic system. The right system motor function is protected by a
hydraulic fuse. The fuse will prevent operation of the motor it diverts too
much flow from the right system to prevent adequate operation of the flight
controls, since operation of the PTU assumes loss of the left hydraulic
system and only right system pressure is available for flight controls. The
fuse will activate if the right system flow to the PTU exceeds thirty-four (34)
gallons per minute.
The switches controlling the operation of the PTU are located on the PWR
XFR UNIT of the HYDRAULIC CONT panel on the cockpit overhead,
shown in Figure 7. The left switch is labelled OFF / ARM, and is normally
selected to the ARM position. If the switch is selected OFF, the amber NOT
ARM legend in the switch will illuminate. When the switch is armed, the
shutoff valve directing right system pressure to the motor of the PTU will
open whenever left system pressure drops below fifteen hundred (1,500)
psi to provide pressurization of the left system. Automatic operation will be
inhibited, however, if the fluid quantity in the left system is one (1) gallon or
less or if the temperature in the right system reservoir exceeds one
hundred four point four degrees centigrade (104.4°C). The right PWR XFR
UNIT switch, labelled ON, will open the shutoff valve and operate the PTU
regardless of left system fluid quantity or right system temperature (the
amber ON legend in the switch will illuminate when the switch is depressed
to the on position).
Whenever the PTU is operating, pressurized left system fluid is available to
actuate the following components:
•Flaps
•Landing gear
•Brakes
•Nose wheel steering
•Ground spoiler servos
•Standby Electrical Power System Hydraulic Motor Generator (HMG)
F. Standby Electrical Power System Hydraulic Motor Generator (HMG):
The Hydraulic Motor Generator (HMG) is located in the left main landing
gear wheel well. The HMG is an electrical generator that can be driven by
left system or PTU pressure rotating the generator shaft. Operation of the
Standby Electrical Power System HMG is controlled by the STANDBY
ELECTRICAL POWER MASTER switch on the cockpit overhead (see
Figure 10). When the switch is selected ON (the amber ON legend in the
switch will illuminate), a solenoid controlled valve will open, porting left or
PTU hydraulic pressure to the variable piston drive of the generator. The
generator has a normal operating speed of eight thousand (8,000) rpm and
is capable of supplying ten thousand volt /amperes (10k VA) of Alternating
Current (AC) power. For more information on the Standby Electrical Power
System HMG, see section 2A-24-00: Electrical Power.
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G. System Displays:
Performance of the hydraulic system components may be monitored on the
Hydraulics or Summary synoptic 2/3 window displays or the Ground
Service system 1/6 window display. The Hydraulics synoptic display offers
the most comprehensive view of the left and right systems, containing the
following information:
•Hydraulic pressure - displayed in a range from 0 - 4,000 psi with a
100 psi resolution (readings below 200 psi are shown as 0 psi). The
pressure readouts are displayed in white when within the range of
1,500 to 3,400 psi, otherwise the readout is shown in amber
•Hydraulic pumps - displayed symbolically and color coded to reflect
operating status for engine-driven, AUX and PTU pumps. The
pumps are represented by a round circle with three green vanes
when pumps are operating and producing pressures ≥1,500 psi, the
symbol changes to a white circle with no vanes if the pumps are not
operating or the shutoff valve to the pump is in transition, and if
pump operation is unsatisfactory (low pressure < 1,500 psi,
overheated or overloaded) the pump is illustrated by an amber circle
without vanes.
•Hydraulic valves - shown as circles with an internal line representing
a standard gate valve. The internal symbol line is aligned with the
respective hydraulic line when the valve is open, perpendicular to
the hydraulic line when closed, or shown as a diagonal when in
transition. The color of the valve representation corresponds to
operating conditions: green when in agreement with commanded
position and pressure ≥1,500 psi, amber when valve position does
not correspond to commanded position, and white for all other
conditions (off).
•Hydraulic temperatures - displayed for each reservoir with a range
of -60° to 150°C with a resolution of 1°C. The digital readouts are
green when temperatures are between 79.4° and 104.4°C, white
when below 79.4°C, and amber when above 104.4°C.
•Hydraulic quantities - system fluid is displayed numerically in gallons
with a resolution of 0.1 gal for the left, right and AUX portion of the
left reservoir, and graphically by a green raster bar graph within the
volume of the reservoir symbols. Labels depicting full and low fluid
levels are shown to the side of the reservoirs, with full corresponding
to 4.8 gal for left and 1.6 gal for the right. The low label is set at 3.0
gal for the left (JAR configured aircraft at 2.8 gal) and 1.0 for the
right. When reservoir quantities are zero (0), the green raster graph
is replaced with an “X”.
On the Summary synoptic window, hydraulic pressures and quantities are
shown digitally in colors reflecting system operation - white for normal
ranges and amber for abnormal conditions.
The Ground Service system window has bar graph displays of reservoir
quantities with digital readouts below the graphs in ranges reflecting an
unpressurized condition: 0 -5.8 gal for the left reservoir, 0 - 1.9 gal for the
right, with a resolution of 0.1 gal. Full and Low marks are shown on the bar
graphs representing levels shown in the following table:
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Graph Region Left Quantity Right Quantity
Bottom to Low 0.0 - 3.0 gal * 0.0 - 1.0 gal
Low to Full 3.0 - 4.8 gal * 1.0 - 1.5 gal
Full to Top 4.8 - 5.8 gal 1.5 - 1.9 gal
* JAR configured aircraft have 2.8 gal as Low mark
3. Controls and Indications:
A. Circuit Breakers (CBs):
The following CBs protect components of the left hydraulic system:
Circuit Breaker Name: CB Panel: Location: Power Source:
L HYD S/O LEER A-16 L ESS DC Bus
L HYD QTY LEER A-17 L ESS DC Bus
L HYD PRESS LEER A-18 L ESS DC Bus
HYD CONT LEER B-17 L ESS DC Bus
OILER/HYD PUMPS REER C-9 GND SVC Bus
AUX HYD PRESS LEER C-17 L ESS DC Bus
AUX HYD PUMP LEER C-16 L ESS DC Bus
PTU HYD PRESS REER C-7 R ESS DC Bus
HMG CONT #1 LEER J-12 L ESS DC Bus
HMG CONT #2 REER E-31 BATT Bus
B. Crew Alerting System (CAS) Messages:
The following CAS messages are associated with operation of the left
hydraulic system:
Area Monitored: CAS Message: Message Color:
AUX Boost Pump Pressure Aux Hydraulic Boost
Fail Amber
AUX Pump Pressure Aux Hydraulic Fail Amber
AUX Pump Temperature >
356°F Aux Hydraulic Hot Amber
Aux Pump Fluid Flow Aux Hydraulic Pump
Overload Amber
Hydraulic Reservoir Quantity Hydraulic Quantity Low,
LAmber
Hydraulic Reservoir
Temperature Hydraulic Reservoir Hot, L Amber
Engine-driven Pump and/or
System Pressure Hydraulic System Fail, LAmber
PTU Pump Pressure < 1,500
psi PTU Hydraulic Fail Amber
AUX Pump Pressure Aux Hydraulic On Blue
Standby Electrical Power
MASTER Switch HMG Switch On Blue
Hydraulic Reservoir
Temperature Sensor Hydraulic Temp Sen Fail, L Blue
PTU Pump Pressure PTU Hydraulic On Blue
Standby Rudder Switch Standby Rudder Hyd
On Blue
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4. Limitations:
A. Flight Manual Limitations:
(1) Maximum Reservoir Quantities (Pressurized) As Indicated on
the Hydraulics Synoptic Page:
•Left Hydraulic System: 4.8 gallons
•Right Hydraulic System: 1.6 gallons
Refer to placard in aft equipment bay.
(2) Left And Right Hydraulic System Accumulator Precharge:
1200 psi at 70°F / 21°C, ±25 psi for each 10°F / 5°C difference in
temperature from 70°F / 21°C.
OPERATING MANUAL
PRODUCTION AIRCRAFT SYSTEMS2A-29-00
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Left Hydraulic System
Flow Diagram
Figure 2
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Left Hydraulic System Components
Figure 3
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PRODUCTION AIRCRAFT SYSTEMS 2A-29-00
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Hydraulic Reservoir Quantity Indicators
Figure 4
OPERATING MANUAL
PRODUCTION AIRCRAFT SYSTEMS2A-29-00
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Hydraulic Quantity Block
Diagram
Figure 5
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