1. Análisis del contexto y la idea de negocio
1.4 Análisis del sector económico
The CDU shows exceedance data for each engine. A red exceedance box on the engine display tells maintenance personnel to get BITE data from the CDU. BITE data shows the most current exceedance event and the flight leg. Historical data shows on other CDU pages.
In addition to exceedance data, engine fault data is available on the CDU. All fault messages have a number that is in the fault isolation manual (FIM). Past and present flight fault data may be recalled. The CDU also supplies this data:
ENGINE PANEL
An ENGINE CONTROL Indication light comes on for a major engine fault. This light, on the aft P5 panel, is amber. The airplane must be on the ground for the light to come on. The engine may or may not be running.
Air data faults cause the ALTN amber light to come on. For airplane dispatch, both EEC switches are put to off. This makes both engines run in the hard-alternate mode. This procedure prevents unequal thrust and throttle stagger. The crew must be careful to not exceed the rated engine thrust in this mode.
Fault Isolation
RTE
LEGS
FIX
PREVPAGE N1 LIMIT DIR INTC
NEXTPAGE
HOLD
Engine Panel (P5)
Control Display Unit
ENGINE
FQIS>
a REVERSER
EEC
CONTROLa ENGINE CONTROLa
Power Plant
Thrust Reversers
The thrust reversers (TRs) use electrical control. The TRs operate with hydraulic power. Both TRs are interchangeable between the two engines except for the cascades.
Reverse thrust occurs with a change of fan air direction. When the thrust reversers deploy, the blocker doors close and fan air goes out radially and forward.
When the translating sleeves extend, these events occur:
Thrust Reverser Operation
Deployed Drag Link
(10) Blocker Door Drag Link
Stowed
Reverse Thrust Forward Thrust
(10) Blocker Door
Translating Sleeve
Translating Sleeve Cascades
Thrust Reverser Operation The TR system may be armed only during these conditions:
• Airplane on the ground or less than 10 feet from the ground
• The fire warning switches are in the normal position.
DEPLOY
The TR system arms when movement of the reverse thrust levers sends power to the control valve modules. This energizes solenoids which open valves. The valve modules are in the main landing gear wheel wells. The valves send pressurized hydraulic fluid to
thrust lever. This movement increases reverse thrust power.
STOW
Movement of the reverse thrust lever to the stow position changes the direction of hydraulic fluid. The actuators move the sleeves to the stow position.
The TR hydraulic system pressurizes when you select reverse thrust. It also pressurizes when the automatic restow system energizes.
Each engine TR system gets power from separate hydraulic systems.
Hydraulic system A supplies power to the left engine TR. System B
An automatic restow system
activates when the engine accessory unit (EAU) senses a sleeve out of the stow position.
Thrust Reverser Actuation System Schematic
System A Hydraulics STBY Hydraulics
Stow Deploy Deploy
Ground Stow
Deploy Stow
Fire Warning Switch
Thrust Lever Air
Control Valve Module
Reverser Deployed Engine 1
Interlock Eng Accy
Actuator Angle Resolver
Electronic Engine Control
Unit
28V DC
T/R Sleeve Position
Power Plant
Thrust Reverser Indication The EEC must be on to sense thrust reverser sleeve position. The EEC sends a signal to the DEUs for thrust reverser sleeve position.
A REV indication shows above the N1 indication on the engine display when the thrust reverser operates.
The indication is amber if the thrust reverser is not in the commanded position. The indication is green when the thrust reverser is in the full-deploy position. The indicator is off when the reverser is in the stow position.
The engine accessory unit (EAU) operates a REVERSER fault light.
The lights are on the engine panel on the P5 aft overhead panel. When this fault light comes on, the master caution light also comes on after 15 seconds delay. When the light comes on, do a test of the system.
BITE is on the EAU in the EE compartment for fault isolation.
Thrust Reverser Indication
Engine Display P2 Center
Instrument Panel
P5 Aft Overhead Panel
a REVERSER
EEC
CONTROLa ENGINE
ALTN a ON w
1 ENGINE 2
a REVERSER
EEC
ON w
ALTN a
ENGINE CONTROLa
Engine Panel
Hydraulics
• Hydraulic Systems
• System Distribution
• System Controls
• Servicing
• Maintenance
• Pressure Module Features
TRIPLE REDUNDANCY
System A has one engine-driven pump (EDP) and one electric motor-driven pump (EMDP) for these systems:
• Flight controls
• Flight spoilers
• Landing gear
• Nose gear steering
• Alternate brakes
• Left thrust reverser
• Ground spoilers.
System B has one engine-driven pump and one electric motor-driven pump for these systems:
• Flight controls
• Flight spoilers
• Normal brakes
• Trailing edge flaps
• Leading edge devices
• Right thrust reverser.
The standby system has one electric motor-driven pump that supplies the third power source for the rudder control system. The standby system also supplies the second power source for these systems:
• Thrust reversers
• Leading edge devices.
FLIGHT CONTROLS
Hydraulic systems A and B supply power for all three axes of the flight control system.
MULTIPLE FILTRATION
The hydraulic fluid goes through filters while servicing and during
CONNECTION
A hydraulic service connection in the main landing gear wheel well makes it possible to service all three reservoirs from one location.
LEAK CONTROL FUSES The system pressure lines have fuses to protect the hydraulic system from fluid loss if a major component fails or if a line leaks.
Hydraulic Systems
The three hydraulic systems operate independently at 3000 psi nominal pressure. The three systems are system A, system B, and the standby system. Each system has a
reservoir, pumps, and filters.
The hydraulic fluid is fire resistant.
SYSTEM A
System A uses one engine-driven pump (EDP) and one electric motor-driven pump (EMDP). The system supplies hydraulic power to these systems:
• Flight controls
SYSTEM B
System B uses one EDP and one EMDP. System B supplies hydraulic power to these systems:
• Flight controls
• Normal brakes
• Trailing edge flaps
• Leading edge flaps and slats
• Right thrust reverser
• Flight spoilers
• Alternate nose gear steering
• Alternate gear retraction.
Regulated air from the environmental control system pressurizes system A and system B reservoirs. The air gives a positive supply of hydraulic fluid to each pump. The standby
STANDBY SYSTEM
The standby system, which has a separate electric motor-driven pump, is an auxiliary source of hydraulic power. To operate the standby system, move either of the FLT CONTROL switches to STBY RUD or the ALTERNATE FLAPS switch to ARM. The switches are on the overhead panel. The standby system also operates automatically. Standby hydraulic power supplies pressure to these systems:
• Rudder control system
• Either or both thrust reversers
• Leading edge flaps and slats (full extend only) in the alternate flap mode.
Hydraulic System
Ground Spoilers Rudder Elevator
Thrust Reversers
LE Slats and Flaps Aileron Autopilot
Landing Gear Brakes TE Flaps Flight Spoilers Elevator Feel Elevator Autopilot
Ailerons
Rudder
Thrust Reversers
Normal ReservoirB
System B
Normal
Left Engine
PTU Alternate Reservoir
System A A
Right Engine
LE Devices (Extension Only)
NG, MG Actuation NG Steering
Standby Reservoir Standby System
EDP EMDP
Electrical Backup
EDP (Engine-Driven Pump) Manual Backup
Legend:
EMDP (Electric
Motor-PTU (Power Transfer Unit) Accumulator Backup
T E M
Landing Gear System Transfer Valve (For Landing Gear
Retraction And NG Steering) Manual Extension
A
EDP EMDP EMDP
T
Driven Pump)
Main Deck Cargo Door (737-700C)
Hydraulics
System Distribution FLIGHT CONTROLS
Although system A and system B supply hydraulic power for the primary flight controls, either system alone will operate the ailerons, elevators, and rudder. As a third backup, the ailerons and elevators can operate by manual reversion and the rudder operates by the standby hydraulic system.
Trailing edge flaps normally receive power from system B. They also receive power from an electrical backup system for extension or retraction. The standby system supplies a secondary means to fully extend the leading edge flaps and slats.
The power transfer unit (PTU) supplies a backup source of hydraulic power for normal and/or autoslat operation. The PTU has a hydraulic motor and pump on a common shaft. The PTU receives pressure from system A to turn the motor. The pump of the PTU receives fluid from the system B reservoir. The PTU operates automatically when these conditions are true:
• Airplane in the air
• Trailing edge flap position between up and 15
• Engine-driven pump in system B has low pressure.
Some of the flight spoilers continue to function if either system A or system B pressure is not available.
LANDING GEAR AND BRAKES System A normally supplies pressure for operation (extension and
retraction) of the landing gear.
If engine 1 does not operate for takeoff, system B supplies pressure to retract the landing gear. The landing gear transfer valve changes the pressure supply for the landing gear from system A to system B. All of these conditions are necessary for the landing gear transfer valve to automatically move to the alternate, system B position:
• Airplane in the air
• Landing gear lever not down
• One or both main landing gear not up and locked
• Left engine N2 speed less than 50%.
The nose wheel steering system receives pressure through the nose gear and main gear actuation.
System A normally supplies pressure for nose wheel steering. The landing gear transfer valve moves manually to the alternate (system B) position when these conditions are true:
• Alternate nose wheel steering switch to the alternate position
• Airplane on the ground
• Normal quantity in the system B reservoir.
If system A hydraulic pressure is not available for extension, the landing gear can be extended manually. The manual release, in the flight
compartment, lets the landing gear free-fall to the down and locked position.
The normal brake system gets power
THRUST REVERSERS
System A supplies power to the left thrust reverser and system B supplies power to the right thrust reverser. If there is no primary system (A or B) pressure, the standby system supplies hydraulic power to operate one or both of the thrust reversers.
System Controls
Controls and indicators for the hydraulic system are on the forward overhead panel and the center main panel.
ENGINE-DRIVEN PUMP SWITCHES
The ON position is the normal position for each engine pump switch. The depressurizing valve solenoid does not operate and the valve closes.
ELECTRIC MOTOR-DRIVEN PUMP SWITCHES
The ON position sends power to the electric motor-driven pump (EMDP).
PUMP LOW PRESSURE LIGHTS Amber low pressure lights come on when the pump pressure is less than normal. All low pressure lights operate at the same pressure value.
ELECTRIC MOTOR-DRIVEN PUMP OVERHEAT LIGHTS
The amber lights come on for system A and B EMDPs to show an overheat condition.
FLT CONTROL SWITCHES The flight control switches control hydraulic system pressure to ailerons, elevators, rudder, and elevator feel system.
STBY RUD
Either switch A or B in this position turns on these components:
• The standby pump
• Pressurizes the standby rudder power control unit
• Closes the system A or B flight
OFF—Hydraulic system pressure for either system A or B stops to these components:
• Ailerons
• Elevators
• Rudder
• Elevator feel system.
SPOILER SHUTOFF VALVE SWITCHES
These valves control hydraulic system pressure to the flight spoilers.
• ON—System A or B will supply power to the flight spoilers
• OFF—No system pressure from A or B is available to the flight spoilers.
ALTERNATE FLAPS SWITCH The ARM position operates these functions:
• Turns on the standby pump
• Trailing edge flap bypass valve moves to the bypass position
• Arms the alternate flaps control switch.
STANDBY HYD LOW QUANTITY LIGHT
This light comes on amber when the standby hydraulic reservoir fluid quantity is less than 50% full.
STANDBY HYD LOW PRESSURE LIGHT
This light comes on amber when the standby pump pressure is too low.
The light arms when any one of these conditions are true:
• Either FLT CONTROL switch in the STBY RUD position
• The ALTERNATE FLAPS switch in the ARM position
• The standby system operates
HYDRAULIC SYSTEM PRESSURE INDICATORS
These pressure indicators show hydraulic system A and system B pressure. When both pumps for a system are off, the indicator shows zero pressure. These are the gage pressure ranges:
• Low pressure: 2000 psi
• Normal pressure: 3000 psi
• Maximum pressure: 3500 psi.
HYDRAULIC BRAKE PRESSURE INDICATOR
The indicator shows brake
accumulator pressure. It also shows the accumulator precharge pressure when the accumulator completely bleeds off.
• Normal pressure: 3000 psi
• Normal precharge pressure:
1000 psi.
SYSTEM RESERVOIR QUANTITY INDICATION
The reservoir quantity for system A and system B show digitally in percent of full. The refill level is 76%.
When the quantity is 76% or less, an RF message shows adjacent to the quantity indication.
System A (center main panel):
• 100%-Full: 5.7 U.S. gallons (21.6 liters)
• 76%-Refill: 4.7 U.S. gallons (16.4 liters).
System B (center main panel):
• 100%-Full: 8.2 U.S. gallons (31.1 liters)
• 76%-Refill: 6.9 U.S. gallons (23.6 liters).
The standby system reservoir has a
Hydraulics
LOW PRESSURE
LOW PRESSURE LOW LOW
PRESSURE
HYD PUMPS
ENG 2 ELEC 1 ENG 1 ELEC 2
B
PRESSURE
ALTERNATE FLAPS
LOW PRESSURE
LOW PRESSURE
FEEL DIFF
B FLT CONTROL
A
SPEED TRIM
ON
YAW DAMPER
ON ON
OFF
FAIL
AUTO SLAT FAIL MACH TRIM
FAIL
Alternate Flaps Master Switch Standby Hydraulic Low Pressure Light Standby Hydraulic Low Quantity Light Flight Control
Switches
Flight Control Low Pressure Lights Flight Spoiler Shutoff Valve Switches
Hydraulic System A Pump Low
System B Hydraulic Pump Switches System B
Overheat Light
System A Hydraulic Pump
System A
Hydraulic System B Pump Low Pressure
Overheat Light
Flight Control Panel Hydraulic Panel
Switches Pressure Lights
Lights P5 Forward
Overhead Panel
Hydraulic Brake Pressure Indicator
PRESS
Hydraulic System B
Servicing
All three hydraulic reservoirs fill from a convenient single-point service connection in the right wheel well.
These are the main components:
• Hand pump with suction hose
• Connection for ground cart pressure fill
• Selector valve.
Electrical power is not necessary to read reservoir fluid quantity. System A and B reservoirs have mechanical quantity gauges that are visible from the servicing location.
To fill the hydraulic reservoir, maintenance personnel use either a ground cart that connects to the pressure fill connection or the hand pump and suction hose.
The system B reservoir fills through the standby reservoir. When the system B quantity indicator shows full, both system B and standby reservoirs are full.
Hydraulic system reliability is better because of filtration. System A and B have a pressure, return, and case drain filters. Individual filters in the system supply additional filtration for critical areas such as flight control power units. The standby system has pressure and case drain filters.
Maintenance
Hydraulic system supply and power components are easy to reach. Most of the hydraulic components are in the main wheel well. These are the components in the wheel well:
• System A and B EMDP
• Three reservoirs
• Standby pressure module
• Filters
• Hydraulic servicing station.
High reliability comes from modular units which help fluid flow and reduce the number of necessary fittings. The system A pressure module shows as an example. The pressure module includes these components:
• Two pressure filters
• Two check valves
• Two pressure switches
• Pressure relief valve.
Use of this modular assembly removes many extra tubes and hydraulic connections.
You can replace the entire pressure module or replace individual
components without removal of the module.
Hydraulics
Manual Fill Hand System A
System A
System B
Reservoir Fill Selector Valve
Pump (and Hose) System B
System B Return Filter
Reservoir Fill Pressure Filter
Power Transfer Unit (PTU)
PTU Pressure
EDP Supply Shutoff Valve (2) Reservoir
Module
EMDP
Filter EMDP
System A Pressure
Module System A Return Filter Module
Reservoir
Main Landing Gear Wheel Well (Looking Forward) Reservoir Pressurization Module
System B Pressure Module
Standby Pressure Module
Standby
Standby System Reservoir
System EMDP Engine Accessory Gearbox
Engine-Driven Pump
Pressure Module
The pressure module supplies and filters EDP and EMDP pump pressure to user systems. The module is on the forward bulkhead of the left main gear wheel well. The pressure module includes these features:
• Pressure filters
• Pump low pressure switches
• System pressure transmitter
• Pressure relief valve
• Check valves.
A non-bypass cartridge type filter in the pressure line from each pump filters the fluid before it goes to the user systems. The filter has a
non-A check valve downstream of each pressure filter and each low pressure switch isolates them from the pressure output of the opposite pump. The system pressure transmitter connects to the system pressure module downstream of both one-way check valves. Because of this, the pressure transmitter shows system pressure and not individual pump pressure. The signal from the pressure transmitter goes to the display electronics unit. You can replace each component on the module without module removal.
System A Pressure Module (System B Similar)
EMP Pressure Filter
To Landing Gear Transfer Valve
To Alternate Brake Source Selector Valve and Spoiler Control Valve System Pressure Transmitter
(To Upper Center Display Unit)
EDP Check Valve
To PTU EDP
EMDP PTU Note:
EDP Low Pressure Switch
EMDP Low Pressure Switch
EMDP Check Valve
Pressure Line From EMDP 2
System Relief Valve (Engine-Driven Pump)
(Electric Motor-Driven Pump) (Power Transfer Unit)
FWD