AIRCRAFT ELECTRONIC INSTRUMENT SYSTEMS

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INTRODUCTION: Instruments have a vital role in controlling

aircraft

They are means of communicating data between the aircraft systems and the controller (the Pilot)

Content and format of data displays are standard. Why?

For easier control and less mental effort

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COMMON FORMS OF DISPLAYS

Quantitative

Qualitative

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QUANTITATIVE DISPLAYS:

Data is presented in terms of a numerical value and by the relative position between a pointer or index and a graduated scale

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Example:

An Airspeed Indicator

QUALITATIVE DISPLAYSData is presented in pictorial or symbolic format

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Example:

Attitude Director Indicator

INSTRUMENT PANELS AND LAYOUTS Primary Data must be in the pilot’s line of

vision

Indications are so coordinated as to create a ‘picture’ of the aircraft flight condition

Important for instruments to be properly grouped to maintain coordination

Must assist pilot in observing them with minimum effort

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THE ‘BASIC SIX’ LAYOUT

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Airspeed Indicator

Gyro Horizon

Altitude Indicator

Turn & Bank Indicator Vertical

Speeded Indicator

Direction Indicator

THE BASIC ‘T’ LAYOUT

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Mach & Airspeed Indicator

Attitude Director Indicator Altitude

Indicator

Radio Magnetic Indicator

Horizontal Situation Indicator

Vertical Speed

Indicator

TYPES OF INDICATORS

Analogue Indicators Mechanical Instruments showing a pointer moving on a dial or

scale.

Used mainly in older generation Aircraft

Electronic displays Instrumentation in the form of a CRT or LCD display.

Used in modern Aircraft

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Example of an Analogue Instrument:

An Analogue Altimeter

which indicates ‘Altitude’

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Example of an Electronic Instrument:

Electronic Attitude Director Indicator (EADI) or Primary Flight Display. It also displays Altitude

and Airspeed

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Another example of an Electronic Instrument:

Electronic Horizontal Situation Indicator

(EHSI) or Navigation Flight Display. It also

displays Weather information

THE ANALOGUE COCKPIT

13Boeing 737-200 Cockpit – all instruments are analogue

Basic T-displays

THE ‘GLASS’ COCKPIT

14Airbus A320 cockpit – Almost all instruments are

digital displays

Basic T layout display

15Airbus A340 cockpit – Almost all instruments are digital displays

Basic T layout display

16Boeing 737 ‘New Generation’ Glass Cockpit

Basic T layout display

17Another Glass Cockpit – The Boeing 747 modern generation aircraft

Basic T layout display

MAJOR DIFFERENCE BETWEEN COCKPITS

Analogue Basic T-layout consists of separate analogue instruments

Separate T-layout for Pilot and Co-pilot

Glass Basic T-layout grouped in 2 CRT’s

One common T-layout spread on whole instrument panel

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ELECTRONIC INSTRUMENT SYSTEMS All modern aircraft use electronic display devices

EIDS (Electronics Instrument Display Systems)

EFIS (Electronic Flight Instrument Systems)

Highly sophisticated technology providing the pilot with attitude and navigation information

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ELECTRONIC INSTRUMENT SYSTEMS

Divided into two main sections: Electronic Flight Instrument System (EFIS)

Aircraft and System Monitoring Instrument System

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BASIC AIRCRAFT EFIS SYSTEM

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Pilot's Instrument Panel

RemoteLight Sensor

ADIor

PFD

ADIor

PFD

HSIorND

HSIorND

ControlPanel

ControlPanel

ADI ADI

HSI HSIAlternateSelectorSwitches

CentreSymbol

Generator

LeftSymbol

Generator

RightSymbol

Generator

Left IRSVOR 1

Left ADCWXR

Loc 1

Centre IRSVOR 3

Left/Right ADCWXR

Loc 1/2

Right IRSVOR 2

Right ADCWXR

Loc 2

Inputs

22The Airbus A320 EIS Cockpit Layout

PFD or EADI –

Displays Attitude, Airspeed, Altitude,

etc.

ND or EHSI –

Displays Nav. Info.

And Weather

ECAM system displays

MCDU

Printer

FEATURES OF THE EIS SYSTEM

All is controlled by a Central Processing Unit (Data Management Unit)

Parameters, Error messages and maintenance data can be retrieved via MCDU or a Printer

Data filtering: Important data accentuated; temporary unimportant suppressed

Information can be transferred from one monitor to another

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MORE FEATURES AND ADVANTAGES OF EIS SYSTEMS

Variability and Variety Coloured Displays All monitors/displays for the system are

the same (ie: less components needed) Brightness controlled automatically

depending upon the level of sunlight Data can be sent via Radio to ground

(ACARS – Arinc Communication Addressing and Reporting Systems)

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ONE DISADVANTAGE HOWEVER:

In bright sunlight it might be more difficult to read monitor indications than it was with analogue indicators.

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MONITORING SYSTEMS

Part of Electronic Instrument System:

On Airbus: ECAM system (Electronic Centralized Aircraft Monitoring)

On Boeing: EICAS system (Engine Indication and Crew Alerting System)

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ECAM SYSTEM:

Monitors aircraft functions and relays them to the pilots

Produces messages detailing failures

In certain cases lists procedures to undertake to correct problems

Colour coded warning scheme helps pilots to instantly assess the situation

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EFIS/ECAM SYSTEM COMPONENTS

(AIRBUS)

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MCDU

Engine/warning CRT

System/Status CRTECAM Control

Panel

Printer

PFD ND CRT control and transfer

Engine Parameters Fuel on Board Flight Control

position Warning/caution

messages Memo (when no

failure exist)

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The Engine/Warning CRT Display shows:

System synoptic diagrams

Status messages

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System/Status CRT Display shows:

THE ECAM CONTROL PANEL

Allows selection of system/status pages Suppression and recall of

warning/caution messages Pressing ‘ALL’ will allow successive

presentation of all system pages. 31

MCDU (Multifunction Control & Display Unit)

The heart of the A320/319. Everything that the airbus

can do, can be controlled from this unit, including Maintenance Tests.

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The MCDU and Printer

• Aircraft Performance Data as well as Maintenance Data can be printed on a Printer.

CRT SWITCHING

Data can be transferred between displays

Very useful in the case of CRT failure 33

EICAS SYSTEM:

Provide aircraft engines parameters such as RPM, temperature values, fuel flow, etc.

Monitors systems like hydraulic, air-conditioning, electrical, etc.

Generates crew annunciations and warnings.

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EFIS/EICAS SYSTEM COMPONENTS (BOEING) 35

EICAS Caution and Annunciation Panel

Engine Primary Display

Engine Secondary Display or Status/Maintenance Display

CRT switching Control Panel

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EICAS Display Units

Engine Primary Display and Warning

Display

Engine Secondary Display and

Status/Maintenance Display

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EICAS Warning and Caution Annunciation Panel

ECAM/EFIS/EICAS DISPLAY MESSAGE COLOUR CODING:

RED: Warning AMBER: Caution GREEN: Normal Operation BLUE: Action to be carried out

In addition to the CRT display, warnings and cautions generate an attention getter and audible sound in the cockpit.

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