Engines - EICAS (RB211)

Amendment: B757-300 EGT Exceedances.

Introduction

The Engine Indication and Crew Alerting System (EICAS) consolidates engine and selected subsystem indications as well as crew alerting functions. The system includes two color cathode ray tubes (CRTs), two computers and a control panel.

Eicas Computer Select Switch.

A Computer Selector determines which computer controls EICAS CRTs. When the selector is in the AUTO position the Left computer is used. If the Left computer fails, control switches to the right computer. When the L position is selected only the left computer can control the CRTs. When the selector is in the R position only the right computer can control the CRTs. This can be used to correct display faults not automatically detected by the system.

The brightness controls are used to adjust the brightness level of the CRTs. The inner knob controls the upper display brightness and the outer knob controls the lower display brightness. Turning either knob adjusts the brightness level of both displays by the same amount. To adjust the brightness level of a single display, one knob must be held stationary while the other knob is adjusted.

Engine Indications

Primary and secondary engine indications are provided. Engine indications are displayed on the EICAS display. In addition, annunciator lights and a liquid crystal Standby Engine Indicator are provided to monitor engine operation.

Primary Engine Indications

RB211 Primary Engine Indications.

EPR, N1 and EGT are the primary engine indications [and] are displayed on the upper EICAS display.

Warning, caution and advisory messages, which indicate system faults, also appear on the upper CRT. This combination of primary engine indications and crew alerting messages is called the EICAS Primary Display.

EICAS records RPM and EGT exceedance conditions in an auto event memory. The maximum exceedance value is displayed in smaller white numbers below the actual value counter.

Secondary Engine Indications

RB211 Secondary Engine Indications. N2, N3, Fuel Flow, Oil Pressure, Oil Temperature, Oil Quantity and Engine Vibration are secondary engine indications [and] are displayed on the lower EICAS display.

EICAS Display Switches The secondary indications can be displayed by pushing the Engine Display Switch (the ENGINE switch on the EICAS control panel). The secondary engine indications are automatically displayed when:

When the STATUS switch is pushed, the lower EICAS display changes to show the Status Page for other pre-flight checks, typically including hydraulic contents, APU EGT and Oxygen contents.

Normal Display Format

Non Normal Amber

Primary engine indications and the N2, N3 and Fuel Flow indications are digital readouts and round dial/moving pointer indications.

The digital readouts display numerical values while the moving pointers indicate relative value.

Oil Pressure, Oil Temperature, Oil Quantity and Engine Vibration indications are both digital readouts and vertical indication/moving pointers. All digital readouts are enclosed by boxes. The dial and vertical indications display the normal operating range, caution range and operating limits (as applicable).

Normal operating range is displayed on a dial or vertical indication in white.

Non-Normal Indications

The Oil Temperature and Oil Pressure vertical indications have caution ranges displayed by amber bands. If oil temperature or oil pressure reaches the caution range, the digital readout, digital readout box, and pointer all change color to amber.

Non Normal

N1, EGT, N2, N3, Oil Pressure, and Oil Temperature indications have operating limits indicated by red lines.

If one of these indications reaches the red line, the digital readout, box, and pointer change color to red for that indication.

The EGT indication has a maximum continuous limit represented by an amber band. If EGT reaches the maximum continuous limit, the digital indication, box, pointer, and dial all change color to amber.

EGT, N1, N2 and N3 indications are inhibited from changing to amber during takeoff or go-around for five minutes.

The inhibit is extended to ten minutes for single-engine operation.

The red line limits for these parameters are not inhibited. The EGT indication has a maximum takeoff limit displayed by a red line. If EGT reaches the maximum takeoff limit, the digital indication, box, pointer and dial, all change color to red.

The maximum EPR limit is indicated by an amber line at the top of the EPR dial. The EPR indication does not change color when maximum EPR is reached. The reference/target EPR indication displays the FMS reference or target EPR. The commanded EPR indication displays the EEC calculated EPR commanded by thrust lever position.

Automatic Call-up

EICAS Incorporates an automatic call-up feature that displays information automatically when necessary.

If the EICAS Secondary Display is not in view and either N2 or N3 RPM reaches the amber Band or Red line limit, both engine N2 or N3 Indications are automatically displayed. Should oil Pressure or Temperature reach the Amber Band or Red line limit, or should the oil quantity decrease into the low quantity band, all oil parameters for both engines are automatically displayed. If the engine vibration reaches the amber band, both engine vibration displays appear on EICAS. If the status page is displayed when a secondary engine exceedance occurs, the status page is automatically replaced by the engine exceedance parameters. If status is selected after a secondary exceedance has occurred, the status page is displayed and the engine exceedance appears on the upper CRT in a partial, compacted mode.

EICAS records RPM and EGT exceedance conditions in an auto event memory. The maximum exceedance value is displayed in smaller white numbers below the actual value counter.

Special Condition Annunciations

During start, a red Maximum Start EGT radial appears at 570°C on the respective EGT display. This EGT limit remains in view until the engine start is completed.

The N1 parameter displays a green TAI annunciation when the engine anti-ice is on.

Compact Display Format

RB211 EICAS Compact Display Format. In compact format, primary and secondary engine indications are combined on the same display. The EPR and N1 displays are the same as the normal displays. All other indications change to digital readouts only. If an amber or red line parameter for a digital indication is exceeded, the digital indication changes color to amber or red (as does the box that appears around an EGT indication).

Primary and secondary engine indications are displayed on EICAS in compact format whenever a CRT fails.

Note : 'Compact Display Mode' is also referred to as 'Full Engine Mode' in the Warning Systems section.

Engine Secondary Data Cue

EICAS Upper Secondary Cues. A series of blue V V V V V are visible on the lower left corner of the upper EICAS CRT any time engine data is displayed on the lower EICAS CRT. If for some reason the engine data is not visible, the STATUS display switch may be used to allow the engine data to come up partially compacted on the upper EICAS CRT display.

Standby Engine Indicator (SEI)

RB211 Standby Eicas.

With the Standby Engine Indicator selector in AUTO:

  • display is blank with AC power on the airplane and EICAS operative.
  • standby engine indications in view when:
    • AC power is lost (EPR not displayed).
    • Either CRT failed and Status selected on the ground.
    • EICAS (both computers) failed.

Engine Pressure Ratio

P1 Probe Engine Pressure Ratio (EPR) is the primary thrust parameter used for monitoring and setting power.

EPR is directly related to engine gross thrust. The EPR indicating system uses the ratio of pressure signals from LP compressor cold (PF) exhaust stream, and engine air intake pressure (P1) to provide an indication of engine thrust in flight compartment. The P1 probe is secured at the top center position of the inner cowling, protrudes into the air intake and senses air inlet pressure. The probe is protected from ice formation by an electrically heated system.

Annunciations associated with EPR are:

Controls