757 EICAS

RM&E Instructor

757 EICAS

• DESCRIPTION AND OPERATION

• COMPONENTS

• MAINTENANCE

• Q & A

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The engine Indication and Crew Alerting System (EICAS) includes two color Display Units (DU), two computers, and two control panels. In addition to these components we have cancel/recall switches , and captain’s and first officer’s master caution lights, jointly perform the various EICAS functions.

The EICAS computer process and formats data to display all engine and airplane system information required by the crew. Only one computer is used at any particular time for displaying the data on both display units. The left computer is always the primary one and right is secondary. Manual computer selection can be done on the display control panel.

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EICAS is designed to categorize alerts and displays according to function and usage. This results in three modes of display:

•Operational Mode•Status Mode•Maintenance mode

Operational Mode display those engine parameters required on the ground and in flight operation and provide monitoring of the airplane and engine subsystems. The upper DU is dedicated full time to primary engine parameters and alert messages for monitoring by the crew. The lower DU shows secondary engine parameters.

Status Mode provide subsystem parameters as well as status messages on the lower DU. This are used by the crew to determine readiness of the airplane for dispatch and closely associated with the MEL.

Maintenance Mode provide airplane subsystems parameters and maintenance messages on the lower DU. This data is available on the ground only for post-flight maintenance and troubleshooting action.

EICAS DISPLAY CATEGORIES

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EICAS OPERATIONAL MODE

Primary engine parameters displayed on the upper DU are EPR, N1 and EGT.

This are required to set and monitor thrust. All primary parameters are displayed by a digital readout and an analog pointer.

Alert Messages are display in the upper DU left corner.

Secondary Engine Parameters – N2, N3, fuel flow, oil pressure, oil temperature, oil quantity and vibration – are displayed on the lower DU at power up or when manually selected on the display selector panel. Secondary parameters are displayed by a digital readout and an analog pointer.

EICAS automatically display engine exceedance condition and the respective color for fast crew attention and action.

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EICAS ALERT MESSAGES & CANCEL/RECALL

Alert messages displayed on the upper DU are divided by priority:• Warnings - Red required immediate action.• Cautions - Yellow.• Advisories -Yellow and are indented.• White - data or communication.

Cancel and Recall switches control the display of this messages,

Cancel remove any caution and advisory messages from the upper display and will show the next page of Messages if any. RECALL switch will return to view those Messages that are still applicable.

Warning Messages can not be canceled due to the level of importance related to them.

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EICAS DISPLAY CONTROL PANEL

The display select panel provides all control function to the EICAS computer units system operation both in flight and on the ground. The display select panel functions include:• Display format selection:

ENG and STATUS.•Recording subsystem parameters:

EVENT RECORD• Computer source selection:

L, both and R.

• Display brightness control:upper and lower.

• Thrust reference setting control: AUTO/MANUAL

• Clearing/display engine exceedance data: MAX IND RESET

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The Status Mode display is selected by manually pressing the STATUS switch on the display select panel. Data needed by the crew to determined readiness for dispatch is displayed on the upper left corner.

On the upper right corner the following are displayed

• HYD QTY and PSI.•APU RPM/EGT all displayed in digital format.• Crew O2 PSI.

In addition on the lower left corner analog pointers are used to indicate the position of the Rudder, Elevators and Aileron control surfaces.

The status mode can be useful in flight for anticipating possible ground maintenance action that will be required if equipped or activated prior dispatch. For this function, a STATUS cue is provided in the upper left corner lower DU whenever a change in status Msg occurs while the status page is not being displayed.

For specific messages refer to the FIM, if a DU fails in flight, the status cue and status displays are inhibited until airplane is on the ground.

EICAS STATUS MODE

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EICAS MAINTENACE MODE/PANEL

There are five maintenance formats with on the EICAS Maintenance Mode. They are designed to provide maintenance information to aid the ground crew in troubleshooting and verification testing of the major subsystems. They are also used to record systems parameters on the ground or at the time of an in-flight fault for later readout on the ground

The five different formats are displayed in the lower DU and access from the EICAS Maintenance Panel this provides all the controls functions for maintenance and troubleshooting information , the I/O signals interfaces with the air-ground relay and the display panel:

• Environmental Control Systems/Messages - ECS/MSG• Electrical/Hydraulic - ELEC/HYD•Performance/Auxiliary Power Unit – PERF/APU• Engine Exceedance – ENG EXCD•The Configuration Porting – CONF/MCDP

The EICAS maintenance panel contains BITE switch to initiate the SELF bite function of the two computers.

Also on the Maintenance control panel contains the AUTO/MANUAL EVENT read switches and REC/ERASE switches.

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EICAS AUTO AND MANUAL EVENT DISPLAY & RECORDING

EICAS feature automatic event recording of the subsystems parameters . Whenever certain auto or manual events messages are initiated by one of the following subjects:• APU subsystem.• Electrical subsystem.• Engine performance• Environmental control system.• Hydraulic subsystem.

This events are recorded on a nonvolatile memory for later readout and evaluation. The AUTO (or MANUAL) switch on the maintenance panel is use to access and erase this pages.

The Manual Event recording will store discrete from engine parameters or either the ECS/MSG, ELEC/HYD, or PERF/APU maintenance formats. The last data stored overwrites previously stored data, only the last data is available for review.

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RH IDG High out tempDate and time

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To erase the auto recorded values of engines exceedance, call up the ENG EXCD page by pressing the ENG EXCD switch on the maintenance panel and then press the ERASE switch.

Since the Stored exceedance are automatically displayed when the form is called up, the AUTO or MAN events read switches do not have to be used. You must also clear exceedance from the Display Select Panel.

ENGINE EXCEEDANCE DATA

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EICAS COMPUTERS

The EICAS computer are located in the main electronic equipment compartment on the E4-2 rack. The computer unit perform all interface, data processing, control and display generation function required and is software controlled.

The front case has no system lights, BITE or controls. There is a connector for software load with the appropriate tool or equipment. There is also a data load point in the flight deck behind the F/O on P61.

115 VAC is supplied from the respective right and left ac buses

and the circuit breakers are located on the overhead P11 panel. Normally (AUTO) the left computer is on command of displays and the right computer is on backup mode in case the left fails. Manual selection of the active computer is provided by selecting L or R rather than the AUTO position .

Care should be taken when replacing this computer due to electrostatic sensitivity devise.

P61 data port

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The EICAS display units (DU) provide a multicolor (red, yellow, cyan (light blue), magenta (pink), white, and green) CRT presentation of EICAS data.

Video display and deflection signals from the EICAS switching modules are provided to drive the CRTs.

Manual and automatic intensity signals are provided from the display select panel and from remote light sensors in the upper right corner of the front panel.

EICAS DU problems that are detected within each unit like, beam stuck on or off, failure discrete, or over temperature will cause the unit to shut down automatically.

The DU are interchangeable, to remove, unscrew the handle, lift and pull out, refer to the AMM for proper procedure.

DISPLAY UNITS (DU)

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EICAS BITE test can only be accomplished when the airplane is on the ground and the parking brake set.

The EICAS self test mode is initiated by pressing the TEST switch on the EICAS maintenance panel. After depressing the TEST switch, the DUs will display:

• Identical formats with the message “TEST IN PROCESS”.• Master CAUTION lights and the beeper tone are acute.• Level B aural command output signal are generated.• The master WARNING lights, the CONFIG light and siren are

activated.• The takeoff ground signal is generated.• The SEI comes on if selected on auto.

The computer will test the interface and circuits of the complete EICAS system and will display all characters and colors. The FIM is used for any faults noted.

When the test is completed a massage: TEST OK, SELF TEST COMPLETED or TEST FAIL is displayed.

 

EICAS BITE OPERATION

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STANDBY ENGINE INDICATOR

The Standby Engine Indicator(SEI) provides primary Engine information to the flight crew in the event of an EICAS failure, which will result n the loss of the normal primary engine Parameters displays.

When operating , the SEI presents digital LCD Displays of the primary engine parameters. This displays include EPR, N1, EGT and N3 and the max values are shown on red decals next to the digits. The SEI is controlled by a switch on the front with two positions, ON and AUTO.

To perform a display test, a spring loaded switch located opposite to the On/off switch is used, the digital numbers will read ones and eight.

This is a LRU and does not required special software. The engine placards must be removed from the old and installed on the new one.

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Q&A