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These materials are to be used only for the purpose of individual, private study and maynot be reproduced in any form or medium, copied, stored in a retrieval system, lent, hired,rented, transmitted, or adapted in whole or in part without the prior written consent ofJeppesen.

Copyright in all materials bound within these covers or attached hereto, excluding that materialwhich is used with the permission of third parties and acknowledged as such, belongs exclusivelyto Jeppesen.

Certain copyright material is reproduced with the permission of the International Civil AviationOrganisation, the United Kingdom Civil Aviation Authority, and the Joint Aviation Authorities(JAA).

This book has been written and published to assist students enrolled in an approved JAA AirTransport Pilot Licence (ATPL) course in preparation for the JAA ATPL theoretical knowledgeexaminations. Nothing in the content of this book is to be interpreted as constituting instruction oradvice relating to practical flying.

Whilst every effort has been made to ensure the accuracy of the information contained within thisbook, neither Jeppesen nor Atlantic Flight Training gives any warranty as to its accuracy orotherwise. Students preparing for the JAA ATPL theoretical knowledge examinations should notregard this book as a substitute for the JAA ATPL theoretical knowledge training syllabuspublished in the current edition of “JAR-FCL 1 Flight Crew Licensing (Aeroplanes)” (the Syllabus).The Syllabus constitutes the sole authoritative definition of the subject matter to be studied in aJAA ATPL theoretical knowledge training programme. No student should prepare for, or isentitled to enter himself/herself for, the JAA ATPL theoretical knowledge examinations withoutfirst being enrolled in a training school which has been granted approval by a JAA-authorisednational aviation authority to deliver JAA ATPL training.

Contact Details:

Sales and Service DepartmentJeppesen GmbHFrankfurter Strasse 23363263 Neu-IsenburgGermany

Tel: ++49 (0)6102 5070E-mail: [email protected]

For further information on products and services from Jeppesen, visit our web site at:www.jeppesen.com

© Jeppesen Sanderson Inc., 2004 All Rights Reserved

JA310107-000 ISBN 0-88487-357-9 Printed in Germany


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PREFACE_______________________

As the world moves toward a single standard for international pilot licensing, many nations haveadopted the syllabi and regulations of the “Joint Aviation Requirements-Flight Crew Licensing"(JAR-FCL), the licensing agency of the Joint Aviation Authorities (JAA).

Though training and licensing requirements of individual national aviation authorities are similar incontent and scope to the JAA curriculum, individuals who wish to train for JAA licences needaccess to study materials which have been specifically designed to meet the requirements of theJAA licensing system. The volumes in this series aim to cover the subject matter tested in theJAA ATPL ground examinations as set forth in the ATPL training syllabus, contained in the JAApublication, “JAR-FCL 1 (Aeroplanes)”.

The JAA regulations specify that all those who wish to obtain a JAA ATPL must study with aflying training organisation (FTO) which has been granted approval by a JAA-authorised nationalaviation authority to deliver JAA ATPL training. While the formal responsibility to prepare you forboth the skill tests and the ground examinations lies with the FTO, these Jeppesen manuals willprovide a comprehensive and necessary background for your formal training.

Jeppesen is acknowledged as the world's leading supplier of flight information services, andprovides a full range of print and electronic flight information services, including navigation data,computerised flight planning, aviation software products, aviation weather services, maintenance

information, and pilot training systems and supplies. Jeppesen counts among its customer baseall US airlines and the majority of international airlines worldwide. It also serves the large generaland business aviation markets. These manuals enable you to draw on Jeppesen’s vastexperience as an acknowledged expert in the development and publication of pilot trainingmaterials.

We at Jeppesen wish you success in your flying and training, and we are confident that yourstudy of these manuals will be of great value in preparing for the JAA ATPL ground examinations.

The next three pages contain a list and content description of all the volumes in the ATPL series.


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ATPL Series

Meteorology (JAR Ref 050)

The Atmosphere Air Masses and Fronts

Wind Pressure System

Thermodynamics Climatology

Clouds and Fog Flight Hazards

Precipitation Meteorological Information

General Navigation (JAR Ref 061)

Basics of Navigation Dead Reckoning Navigation

Magnetism In-Flight Navigation

Compasses Inertial Navigation Systems

Charts

Radio Navigation (JAR Ref 062)

Radio Aids Basic Radar PrinciplesSelf-contained and Area Navigation Systems

External-Referenced Basic Radio Propagation TheoryNavigation Systems

Airframes and Systems (JAR Ref 021 01)

Fuselage Hydraulics

Windows Pneumatic Systems

Wings Air Conditioning System

Stabilising Surfaces Pressurisation

Landing Gear De-Ice / Anti-Ice Systems

Flight Controls Fuel Systems

Powerplant (JAR Ref 021 03)

Piston Engine Engine Systems

Turbine Engine Auxiliary Power Unit (APU)

Engine Construction

Electrics (JAR Ref 021 02)

Direct Current Generator / AlternatorAlternating Current Semiconductors

Batteries Circuits

Magnetism


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Instrumentation (JAR Ref 022)

Flight Instruments

Automatic Flight Control Systems

Warning and Recording Equipment

Powerplant and System Monitoring Instruments

Principles of Flight (JAR Ref 080)

Laws and Definitions Boundary Layer

Aerofoil Airflow High Speed Flight

Aeroplane Airflow Stability

Lift Coefficient Flying Controls

Total Drag Adverse Weather Conditions

Ground Effect Propellers

Stall Operating Limitations

CLMAX Augmentation Flight Mechanics

Lift Coefficient and Speed

Performance (JAR Ref 032)

Single-Engine Aeroplanes – Not certified under JAR/FAR 25(Performance Class B)

Multi-Engine Aeroplanes – Not certified under JAR/FAR 25(Performance Class B)

Aeroplanes certified under JAR/FAR 25 (Performance Class A)

Mass and Balance (JAR Ref 031)

Definition and Terminology

Limits

Loading

Centre of Gravity

Flight Planning (JAR Ref 033)

Flight Plan for Cross-Country Meteorological Messages

Flights Point of Equal Time

ICAO ATC Flight Planning Point of Safe Return

IFR (Airways) Flight Planning Medium Range Jet Transport

Jeppesen Airway Manual Planning

Air Law (JAR Ref 010)

International Agreements Air Traffic Services

and Organisations Aerodromes

Annex 8 – Airworthiness of Facilitation

Aircraft Search and Rescue

Annex 7 – Aircraft Nationality Security

and Registration Marks Aircraft Accident Investigation

Annex 1 – Licensing JAR-FCL

Rules of the Air National Law

Procedures for Air Navigation


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Human Performance andLimitations (JAR Ref 040)

Human Factors

Aviation Physiology and Health Maintenance

Aviation Psychology

Operational Procedures (JAR Ref 070)

Operator Low Visibility Operations

Air Operations Certificate Special Operational Procedures

Flight Operations and Hazards

Aerodrome Operating Minima Transoceanic and Polar Flight

Communications (JAR Ref 090)

Definitions Distress and Urgency

General Operation Procedures Procedures

Relevant Weather Information Aerodrome Control

Communication Failure Approach ControlVHF Propagation Area Control

Allocation of Frequencies


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CHAPTER 1

Air Temperature Measurement

Introduction ...................................................................................................................................................1-1Direct Reading Thermometer........................................................................................................................1-3Electrical Thermometer.................................................................................................................................1-3Static Air Temperature Sensor......................................................................................................................1-4Total Air Temperature Probe.........................................................................................................................1-5

CHAPTER 2

Pitot-Static System

Introduction ...................................................................................................................................................2-1Pitot Tube......................................................................................................................................................2-1Static Source.................................................................................................................................................2-2

Alternate Static Source .................................................................................................................................2-3Combined Pitot-Static (Pressure) Head ........................................................................................................2-4Operating Problems......................................................................................................................................2-5Pitot/Static System Errors .............................................................................................................................2-6

CHAPTER 3

Pressure Altimeter

Introduction ...................................................................................................................................................3-1Pressure Altitude...........................................................................................................................................3-2Density Altitude.............................................................................................................................................3-2The Simple Altimeter.....................................................................................................................................3-2Datum Sub-Scale Settings............................................................................................................................3-3The Sensitive Altimeter .................................................................................................................................3-4

Altimeter Displays .........................................................................................................................................3-4Design Errors ................................................................................................................................................3-7Errors due to Calibration ...............................................................................................................................3-7Blockages and Leakages..............................................................................................................................3-9

Servo Altimeters............................................................................................................................................3-9Operation of a Servo-Altimeter....................................................................................................................3-10Servo-Altimeter Power Failure ....................................................................................................................3-11

Altitude Encoding........................................................................................................................................3-11 Advantages of Servo-Altimeters..................................................................................................................3-11

CHAPTER 4

Vertical Speed Indicator

Introduction ...................................................................................................................................................4-1Principle of Operation ...................................................................................................................................4-1Operation of the VSI .....................................................................................................................................4-2Errors of the VSI ...........................................................................................................................................4-2

Lag................................................................................................................................................................4-2Instrument Error ............................................................................................................................................4-2Manoeuvre Induced Error .............................................................................................................................4-2Faults of the VSI ...........................................................................................................................................4-2Blockages .....................................................................................................................................................4-2Breakage or leakage in the Static Line .........................................................................................................4-2Instantaneous Vertical Speed Indicator (IVSI) ..............................................................................................4-2Operation of the IVSI / ILVSI.........................................................................................................................4-3


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CHAPTER 5

Airspeed Indicator

Introduction .................................................................................................................................................. 5-1Principle of the Airspeed Indicator (ASI) ...................................................................................................... 5-1Operation of a Simple ASI............................................................................................................................ 5-1Sensitive and Servo Airspeed Indicators...................................................................................................... 5-1Calibration of the ASI ................................................................................................................................... 5-2Colour Coding of the ASI ............................................................................................................................. 5-2

ASI Errors .................................................................................................................................................... 5-3 ASI Faults .................................................................................................................................................... 5-5Calculation of CAS to TAS (up to 300 knots) ............................................................................................... 5-6

CHAPTER 6

Machmeter

Introduction .................................................................................................................................................. 6-1Critical Mach Number (Mcrit) ......................................................................................................................... 6-1Principle of Operation................................................................................................................................... 6-2Machmeter Construction and Operation ...................................................................................................... 6-4

Calibration.................................................................................................................................................... 6-4Errors ........................................................................................................................................................... 6-5Blockages and Leakages ............................................................................................................................. 6-5

Accuracy ...................................................................................................................................................... 6-5Serviceability Checks ................................................................................................................................... 6-5

CHAPTER 7

Mach Airspeed Indicator

Introduction .................................................................................................................................................. 7-1Display ......................................................................................................................................................... 7-1VMO Pointer .................................................................................................................................................. 7-1Driven Cursor ............................................................................................................................................... 7-2

Bugs............................................................................................................................................................. 7-2Linkages....................................................................................................................................................... 7-2Errors ........................................................................................................................................................... 7-2

CHAPTER 8

Central Air Data Computer

Introduction .................................................................................................................................................. 8-1The Central Air Data Computer.................................................................................................................... 8-1Conversion of Sensing Pressures................................................................................................................ 8-2Digital Air Data Computer ............................................................................................................................ 8-4


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CHAPTER 9

Basic Magnetism

Introduction ...................................................................................................................................................9-1Magnetic Properties ......................................................................................................................................9-1Fundamental Laws of Magnetism .................................................................................................................9-3Characteristics of Lines of Magnetic Flux .....................................................................................................9-4Magnetic Materials........................................................................................................................................9-5Ferromagnetic...............................................................................................................................................9-5Paramagnetic................................................................................................................................................9-5Diamagnetic..................................................................................................................................................9-5Permeability ..................................................................................................................................................9-6Electromagnetism .........................................................................................................................................9-6

An Electromagnet .........................................................................................................................................9-7Magnetic Moments........................................................................................................................................9-8Period of Oscillation of a Suspended Magnet ...............................................................................................9-8

CHAPTER 10

Terrestrial Magnetism

Introduction .................................................................................................................................................10-1Magnetic Dip ...............................................................................................................................................10-2Earth's Total Magnetic Force ......................................................................................................................10-4Examples ....................................................................................................................................................10-4Magnetic Variation ......................................................................................................................................10-5

CHAPTER 11

Aeroplane Magnetism

Introduction .................................................................................................................................................11-1Types of Aeroplane Magnetism ..................................................................................................................11-1Components of Hard Iron Magnetism .........................................................................................................11-2Components of Soft Iron Magnetism...........................................................................................................11-5

Determination of Deviation Coefficients ......................................................................................................11-6Minimum Deviation .....................................................................................................................................11-7Maximum Deviation ....................................................................................................................................11-7Joint Airworthiness Requirements (JAR) Limits ..........................................................................................11-8Compass Swinging .....................................................................................................................................11-9The Compass Swing Procedure .................................................................................................................11-9

An Example of a Compass Swing.............................................................................................................11-10Deviation Compensation Devices .............................................................................................................11-11

CHAPTER 12

Direct Reading Magnetic Compass

Introduction .................................................................................................................................................12-1

Properties of a Direct Reading Compass....................................................................................................12-2‘E’ Type Compass.......................................................................................................................................12-3Pre-flight Checks.........................................................................................................................................12-4Principle of a Pendulum..............................................................................................................................12-4

Acceleration Errors .....................................................................................................................................12-4Turning Errors .............................................................................................................................................12-7


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CHAPTER 13

Remote Indicating Compass

Introduction ................................................................................................................................................ 13-1RIC Architecture......................................................................................................................................... 13-1Principle of a Flux Detector Element .......................................................................................................... 13-1Flux Detector Unit ...................................................................................................................................... 13-4Operation of the Remote Indicating Compass System............................................................................... 13-5Gyroscope Element.................................................................................................................................... 13-8Heading Indicator....................................................................................................................................... 13-8Modes of Operation.................................................................................................................................... 13-9Synchronising Indicators ............................................................................................................................ 13-9Manual Synchronisation........................................................................................................................... 13-10Operation of an RIC in a Turn .................................................................................................................. 13-10

Advantages of a Remote Indicating Gyro Magnetic Compass ................................................................. 13-11Disadvantages of the Remote Indicating Gyro Magnetic Compass ......................................................... 13-11

CHAPTER 14

Gyroscopic Principles

Introduction ................................................................................................................................................ 14-1Principle of Construction ............................................................................................................................ 14-2Gyroscopic properties ................................................................................................................................ 14-2Types of Gyroscopes ................................................................................................................................. 14-4Power Sources for Gyroscopes.................................................................................................................. 14-6The Disadvantages and Advantages of Air Driven Gyros .......................................................................... 14-7The Disadvantages and Advantages of Electrically Driven Gyros.............................................................. 14-7Gyro Wander.............................................................................................................................................. 14-8Horizontal Axis Gyro .................................................................................................................................. 14-8Vertical Axis Gyro..................................................................................................................................... 14-10Transport Wander .................................................................................................................................... 14-10Examples of Gyro Wander ....................................................................................................................... 14-11

CHAPTER 15Direction Indicator

Introduction ................................................................................................................................................ 15-1Basic Description of the Direction Indicator................................................................................................ 15-1Operation of the Direction Indicator............................................................................................................ 15-2Errors Associated with the Air Driven Direction Indicator ........................................................................... 15-4Use of the Direction Indicator (DI) .............................................................................................................. 15-4

Advanced Use of the Direction Indicator .................................................................................................... 15-4Sample Calculation .................................................................................................................................... 15-5


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CHAPTER 16

Artificial Horizon

Introduction .................................................................................................................................................16-1 Air driven (Classic) Artificial Horizon ...........................................................................................................16-3Construction................................................................................................................................................16-3Operation ....................................................................................................................................................16-4Erection System..........................................................................................................................................16-5Errors ..........................................................................................................................................................16-6Electrically Driven Artificial Horizon.............................................................................................................16-7Construction................................................................................................................................................16-7Torque Motor and Levelling Switch System................................................................................................16-8Fast Erection...............................................................................................................................................16-8Errors ..........................................................................................................................................................16-9Remote Vertical Gyro..................................................................................................................................16-9Standby Attitude Indicator.........................................................................................................................16-10

CHAPTER 17

Turn and Balance Indicator

Introduction .................................................................................................................................................17-1Turn Indicator..............................................................................................................................................17-1Construction and Principle of Operation .....................................................................................................17-1Operation ....................................................................................................................................................17-3Errors ..........................................................................................................................................................17-4Pre-flight Check ..........................................................................................................................................17-4The Balance Indicator .................................................................................................................................17-4Construction and Operation ........................................................................................................................17-4Limitations and Errors .................................................................................................................................17-5Pre-Flight Check .........................................................................................................................................17-5Electrically Driven Turn and Balance Indicators..........................................................................................17-5Typical Indications on a Turn and Balance Indicator...................................................................................17-6

CHAPTER 18Turn Co-ordinator

Introduction .................................................................................................................................................18-1Principle of Operation .................................................................................................................................18-2


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CHAPTER 19

Inertial Navigation System

Introduction ................................................................................................................................................ 19-1The Principle and Construction of an Accelerometer ................................................................................. 19-1Performance .............................................................................................................................................. 19-3Operation of a Gyro-Stabilised Platform..................................................................................................... 19-3Setting-up Procedures ............................................................................................................................... 19-6Levelling..................................................................................................................................................... 19-6

Alignment ................................................................................................................................................... 19-7Levelling and Alignment ............................................................................................................................. 19-7Corrections................................................................................................................................................. 19-7Coriolis ....................................................................................................................................................... 19-8Centripetal Acceleration ............................................................................................................................. 19-8Wander Azimuth System............................................................................................................................ 19-9The Schuler Tuned Platform ...................................................................................................................... 19-9Errors ....................................................................................................................................................... 19-11The Advantages and Disadvantages of an INS........................................................................................ 19-12Mode Selector Panel................................................................................................................................ 19-13Control Display Unit ................................................................................................................................. 19-14

CHAPTER 20

Inertial Reference System

Introduction ................................................................................................................................................ 20-1Description of the Strap-Down System ...................................................................................................... 20-1Solid State Gyros ....................................................................................................................................... 20-2Ring Laser Gyro......................................................................................................................................... 20-2Fibre Optic Gyro......................................................................................................................................... 20-3

Advantages and Disadvantages of RLGs .................................................................................................. 20-3 Alignment of the Inertial Reference System............................................................................................... 20-4Performance .............................................................................................................................................. 20-4The Control, Display, and Output from an IRS........................................................................................... 20-4Description of a Typical IRS....................................................................................................................... 20-5IRS Transfer Switch ................................................................................................................................... 20-7IRS Alignment ............................................................................................................................................ 20-7Loss of Alignment in Flight ......................................................................................................................... 20-7

CHAPTER 21

Radio Altimeter

Introduction ................................................................................................................................................ 21-1The Radio Altimeter System ...................................................................................................................... 21-1Principle of Operation of a Radio Altimeter ................................................................................................ 21-3Performance and Accuracy of a Radio Altimeter........................................................................................ 21-4Errors Associated with a Radio Altimeter ................................................................................................... 21-4Leakage Errors........................................................................................................................................... 21-4Mushing Errors........................................................................................................................................... 21-4The Advantages of a Radio Altimeter......................................................................................................... 21-5


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CHAPTER 22

Electronic Flight Instrument System

Introduction .................................................................................................................................................22-1EFIS Architecture........................................................................................................................................22-1Symbol Generator (SG) ..............................................................................................................................22-2Instrument Comparator Unit (ICU) ..............................................................................................................22-2Compression Mode.....................................................................................................................................22-2Temperature Sensing Units ........................................................................................................................22-3Mode Control Panels (MCP) .......................................................................................................................22-3Light Sensors ..............................................................................................................................................22-3

Attitude Director Indicator (ADI) ..................................................................................................................22-3Radio Altitude..............................................................................................................................................22-5Decision Height...........................................................................................................................................22-5Localiser and Glide Slope Indication...........................................................................................................22-5The Horizontal Situation Indicator (HSI)......................................................................................................22-5Plan Mode...................................................................................................................................................22-8VOR and ILS Modes ...................................................................................................................................22-8EFIS/IRS Interface....................................................................................................................................22-10Heading Reference Switch........................................................................................................................22-11HSI Symbology .........................................................................................................................................22-11

CHAPTER 23

Flight Management System

Introduction .................................................................................................................................................23-1The Flight Management Computer System.................................................................................................23-2Command Display Unit ...............................................................................................................................23-4Control Panels ............................................................................................................................................23-5CDU and FMC Terminology........................................................................................................................23-7The Flight Management Computer Memory................................................................................................23-9General FMS Operation............................................................................................................................23-11Pre-Flight ..................................................................................................................................................23-12Enroute .....................................................................................................................................................23-13Lateral Navigation (LNAV) ........................................................................................................................23-13Vertical Navigation (VNAV).......................................................................................................................23-14Operational Notes .....................................................................................................................................23-15Fuel Monitoring .........................................................................................................................................23-16Flight Control and Management Summary................................................................................................23-16

CHAPTER 24

Flight Director System

Introduction .................................................................................................................................................24-1Flight Director Architecture..........................................................................................................................24-1Flight Director Control Inputs ......................................................................................................................24-3The Flight Director Computer (FDC) ...........................................................................................................24-4Mode Control Unit .......................................................................................................................................24-4Flight Director Displays ...............................................................................................................................24-4Flight Director Modes of Operation .............................................................................................................24-6

Attitude Mode..............................................................................................................................................24-6Heading ......................................................................................................................................................24-7

Altitude Hold................................................................................................................................................24-9Localiser/VOR (LOC/VOR) .........................................................................................................................24-9Glideslope (GS) ........................................................................................................................................24-11Go-Around (GA)........................................................................................................................................24-12Mode Annunciator.....................................................................................................................................24-12Operation of the Attitude Director Indicator...............................................................................................24-12The Horizontal Situation Indicator (HSI) Flight Director Commands .........................................................24-14


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CHAPTER 25

Automatic Flight Control System

Introduction ................................................................................................................................................ 25-1Stability and Control Augmentation............................................................................................................ 25-1

Attitude Hold .............................................................................................................................................. 25-1Flight Control.............................................................................................................................................. 25-1Classification of an AFCS .......................................................................................................................... 25-2Control Channels ....................................................................................................................................... 25-2Inner Loop Control (Stabilisation)............................................................................................................... 25-2Operation of an Inner Loop Pitch Stabilisation System .............................................................................. 25-3Outer Loop Control..................................................................................................................................... 25-4Roll Modes ................................................................................................................................................. 25-5Pitch Modes ............................................................................................................................................... 25-7Combined Roll and Pitch Modes................................................................................................................ 25-8

Attitude Sensing......................................................................................................................................... 25-9The AFCS Computer (Signal Processor) ................................................................................................. 25-10Servomotor Actuators .............................................................................................................................. 25-11

Autopilot Terminology .............................................................................................................................. 25-12Cross Coupling......................................................................................................................................... 25-14ILS Coupling ............................................................................................................................................ 25-14

VOR Coupling .......................................................................................................................................... 25-15Stability Problems .................................................................................................................................... 25-16Yaw Damper ............................................................................................................................................ 25-16Mach Trim System ................................................................................................................................... 25-17

Automatic Pitch Trim Control ................................................................................................................... 25-18Interlocks.................................................................................................................................................. 25-20Synchronisation........................................................................................................................................ 25-20Instinctive Cut Out.................................................................................................................................... 25-20

CHAPTER 26

Automatic Landing System

Introduction ................................................................................................................................................ 26-1Basic Requirements for an Automatic Landing System ............................................................................. 26-1

Automatic Landing System Terminology.................................................................................................... 26-2 Automatic Landing System Equipment Requirements ............................................................................... 26-3 Automatic Approach, Flare, and Landing Sequence .................................................................................. 26-4Weather Minima......................................................................................................................................... 26-5ICAO Categorisation for Low Visibility Landing Capabilities ...................................................................... 26-5The Fundamental Landing Requirement.................................................................................................... 26-6System Reliability and Integrity .................................................................................................................. 26-7

CHAPTER 27

Thrust Management Systems

Introduction ................................................................................................................................................ 27-1Determining the Thrust Required ............................................................................................................... 27-1Calculation of Climb and Cruise Thrust...................................................................................................... 27-2Cruising Methods ....................................................................................................................................... 27-3Electronic Engine Control (EEC)................................................................................................................ 27-3Full Authority Digital Engine Control (FADEC) ........................................................................................... 27-3

Autothrottle (A/T)........................................................................................................................................ 27-6Thrust Lever Operation .............................................................................................................................. 27-7Thrust Management via the Autothrottle .................................................................................................... 27-7Thrust Management Computer (TMC) ....................................................................................................... 27-8Thrust Mode Select Panel (TMSP)............................................................................................................. 27-8


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CHAPTER 28

Central Warning System

Introduction .................................................................................................................................................28-1Central Warning System Annunciator Panel ...............................................................................................28-1

Aural Warnings ...........................................................................................................................................28-2

CHAPTER 29

Altitude Alerting System

Introduction .................................................................................................................................................29-1 Altitude Alerting System Operation .............................................................................................................29-1

CHAPTER 30

Ground Proximity Warning System

Introduction .................................................................................................................................................30-1GPWS System Architecture........................................................................................................................30-1

GPWS Modes .............................................................................................................................................30-2Warning System..........................................................................................................................................30-3GPWS Control Panel ..................................................................................................................................30-4Discretionary Response..............................................................................................................................30-5Warning Inhibition .......................................................................................................................................30-6The Reporting of GPWS Events .................................................................................................................30-6Operation of the GPWS ..............................................................................................................................30-6Mode 1........................................................................................................................................................30-6Mode 2........................................................................................................................................................30-7Mode 3........................................................................................................................................................30-8Mode 4........................................................................................................................................................30-8Mode 5......................................................................................................................................................30-10Mode 7......................................................................................................................................................30-10Joint Aviation Requirements .....................................................................................................................30-11

CHAPTER 31

Traffic Collision Avoidance System

Introduction .................................................................................................................................................31-1TCAS I ........................................................................................................................................................31-1TCAS II .......................................................................................................................................................31-1TCAS III ......................................................................................................................................................31-1

Aeroplane Installation .................................................................................................................................31-2Operation of TCAS II...................................................................................................................................31-4TCAS Aural Warnings.................................................................................................................................31-4Information Display .....................................................................................................................................31-5Resolution Advisory / Vertical Speed Indicator (RA / VSI) ..........................................................................31-7TCAS Control Panel....................................................................................................................................31-8

Operating Restrictions ................................................................................................................................31-8


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CHAPTER 32

Mach/Airspeed Warning System

Introduction ................................................................................................................................................ 32-1System Architecture and Operation ........................................................................................................... 32-1Maximum Operating Airspeed Schedule.................................................................................................... 32-2

CHAPTER 33

Stall Warning

Introduction ................................................................................................................................................ 33-1Light Aeroplane Stall Warning Device........................................................................................................ 33-1Transport Category Aeroplane Stall Warning Device................................................................................. 33-2

CHAPTER 34

Recording Devices

Introduction ................................................................................................................................................ 34-1

Flight Data Recorder (FDR) Requirements ................................................................................................ 34-1FDR Design ............................................................................................................................................... 34-3Cockpit Voice Recorder (CVR) Requirements ........................................................................................... 34-3CVR Design ............................................................................................................................................... 34-4

CHAPTER 35

General Engine Instrumentation

Introduction ................................................................................................................................................ 35-1Piston Engines ........................................................................................................................................... 35-1Turbo Propeller Engines ............................................................................................................................ 35-2Gas Turbine Engines ................................................................................................................................. 35-2

CHAPTER 36

Pressure and Temperature Sensors

Introduction ................................................................................................................................................ 36-1Pressure Measurement.............................................................................................................................. 36-1Temperature Measurement........................................................................................................................ 36-3

CHAPTER 37

Pressure and Temperature Indicators

Introduction ................................................................................................................................................ 37-1Pressure Indicators .................................................................................................................................... 37-1Manifold Pressure (MAP) ........................................................................................................................... 37-1Engine Pressure Ratio (EPR) .................................................................................................................... 37-1Fuel and Oil Pressures............................................................................................................................... 37-3Temperature Indicators .............................................................................................................................. 37-3Cylinder Head Pressure ............................................................................................................................. 37-3Exhaust Gas Temperature ......................................................................................................................... 37-3Fuel and Oil Temperatures ........................................................................................................................ 37-4


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CHAPTER 38

RPM Indicators and Propeller Synchroniser Systems

Introduction .................................................................................................................................................38-1Tachometers...............................................................................................................................................38-1Magnetic Drag Tachometer.........................................................................................................................38-1Tacho-Generator and Indicator System......................................................................................................38-2Tachometer Probe and Indicator System....................................................................................................38-3Propeller Auxiliary Systems ........................................................................................................................38-6Synchronisation System .............................................................................................................................38-6Synchrophasing System .............................................................................................................................38-7Operation of a Synchrophasing System......................................................................................................38-8

CHAPTER 39

Engine Torque Measurement

Introduction .................................................................................................................................................39-1Torque Meter ..............................................................................................................................................39-1Negative Torque Sensing ...........................................................................................................................39-3

CHAPTER 40

Vibration Monitoring

Introduction .................................................................................................................................................40-1Vibration Monitoring System .......................................................................................................................40-2

CHAPTER 41

Fuel Gauge

Introduction .................................................................................................................................................41-1Measurement of Fuel Quantity....................................................................................................................41-1

Float Type...................................................................................................................................................41-1Ratio Metre Type Fuel Gauge.....................................................................................................................41-2Capacitance Type of Fuel Gauge ...............................................................................................................41-2Fuel Totaliser ..............................................................................................................................................41-5Fuel Flow ....................................................................................................................................................41-5

CHAPTER 42

EICAS

Introduction .................................................................................................................................................42-1EICAS Architecture .....................................................................................................................................42-1Engine Displays ..........................................................................................................................................42-2Crew Alerting ..............................................................................................................................................42-3

Warnings (Level A) .....................................................................................................................................42-3Cautions (Level B) ......................................................................................................................................42-4 Advisories (Level C)....................................................................................................................................42-4Master Warning/Caution Light.....................................................................................................................42-4Inhibits ........................................................................................................................................................42-4Display Messages.......................................................................................................................................42-4Status..........................................................................................................................................................42-6Maintenance ...............................................................................................................................................42-7EICAS Failure Modes .................................................................................................................................42-7


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CHAPTER 43

ECAM

Introduction ................................................................................................................................................ 43-1Engine / Warning (E/W) CRT Display ........................................................................................................ 43-2The System / Status (S/S) CRT Display..................................................................................................... 43-3ECAM System Architecture........................................................................................................................ 43-3Flight Warning Computers (FWCS)............................................................................................................ 43-4Display management Computers (DMC) ................................................................................................... 43-4System Data Acquisition Concentrators (SDAC)........................................................................................ 43-4ECAM Control Panel (ECP) ....................................................................................................................... 43-4

Attention Getters........................................................................................................................................ 43-5ECAM System Failure................................................................................................................................ 43-6Failure Categorisation................................................................................................................................ 43-6System Operation ...................................................................................................................................... 43-6


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Instrumentation 1-1

INTRODUCTIONThe temperature of air under pure static conditions at the various flight levels is one of the basicparameters required to establish data that is vital to the performance monitoring of modernaeroplanes. The measurement of Static Air Temperature (SAT) by direct means is, however, notpossible for all types of aeroplanes, because the measurement is potentially affected by adiabaticcompression of the air at increased airspeeds. The boundary layer over the outer surface of anaeroplane flying below Mach 0.2 is very close to SAT, but at higher Mach numbers the boundarylayer slows or even stops relative to the aeroplane. This in turn results in adiabatic compression,

which causes the air temperature to rise well above SAT. This increase is known as RAM Rise,and the temperature indicated under such conditions is known as Ram Air Temperature (RAT).

RAT = SAT + RAM Rise or SAT = RAT - RAM Rise

The majority of RAM Rise is due to adiabatic compression because of the airflow coming to rest,with only a relatively small amount due to friction between the surface of the aeroplane and thehigh-speed airflow. The RAM Rise is always pre-calculated and is tabulated or graphed as afunction of Mach number in the Operations or Flight Manual for each type of aeroplane, a sampleof which is shown below.


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Chapter 1 Air Temperature Measurement

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The proportion of RAM rise measured is dependent on the ability of the sensor to sense (orrecover) the temperature rise. The sensitivity is expressed as a percentage and is known as therecovery factor. For example, if a sensor has a recovery factor of 0.80, it measures SAT + 80% ofthe RAM Rise.

A useful approximation of RAM Rise is:

(100

kt TAS )2

For example, for an estimated TAS of 460 kt deduct (100

kt460 )2 from the indicated air

temperature, which is approximately equal to 21°C. If this figure is subtracted from the Indicated

Outside Air Temperature (IOAT), it gives the Corrected Outside Air Temperature (COAT), whichis the best determinable value of the temperature of the air through which the aeroplane is flying,and is that which is required for navigational purposes:

COAT = IOAT – RAM Rise


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Air Temperature Measurement Chapter 1

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Alternatively written as:

TS = 20.2KM+1

MT

Where: TS = SAT in degrees absolute.TM = Indicated temperature in degrees absolute.

K = Recovery Factor.

M = Mach Number.

Various types of air temperature sensors are fitted to aeroplanes, although the particular type isdependent on whether SAT or RAT is required, and the normal operating speed of the aeroplaneon which it is fitted.

DIRECT READING THERMOMETERThis is the simplest type of thermometer, and it only indicates SAT. It consists of a bi-metallic

element in the shape of a helix, which expands and contracts when subjected to temperaturechanges.

As the temperature changes, the helix winds or unwinds, and causes a pointer to rotate against a

scale calibrated in degrees Celsius. This type of thermometer is normally only fitted on low-speedlight aeroplanes, and passes through the fuselage or canopy with the sensitive element projectinginto the airflow. The element is also shielded so that it is not directly affected by solar radiation.

Another method of making a direct reading thermometer is to use a liquid filled bulb and capillarytube, with the bulb mounted externally in the airflow and the capillary tube transmitting the liquidpressure to a Bourdon tube. As the temperature to which the bulb is subjected changes, the liquidexpands or contracts, and causes the Bourdon tube to wind or unwind. This movement of theBourdon tube is connected to a pointer, which moves around a scale calibrated in temperature.

ELECTRICAL THERMOMETERThe resistance of an electrical conductor is dependent on temperature, and its magnitude

changes due to thermal changes, thus altering its ability to oppose current flow when connectedin a circuit. The Electrical (Wheatstone Bridge) Thermometer commonly uses thetemperature/resistance technique.


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Instrumentation1-4

The bridge consists of four resistance arms, which connect across a low voltage source as shownabove. When the system is switched on, current flows in the circuit and divides at point A beforeflowing through R1 and R2 at strengths that vary as the temperature of R4 (positioned outside the

fuselage) alters. At point C the currents re-unite and flow back to the voltage source. If the Bridgeis balanced resistance-wise, no current flows and the moving coil galvanometer (meter) readszero. If the temperature (resistance) of R4 changes, the bridge becomes unbalanced, and theresulting current flowing through the galvanometer registers as a change in temperature.

STATIC AIR TEMPERATURE SENSORThe majority of temperature sensors use a platinum wire element contained either in a probemounted in what is termed a flush bulb configuration, or in a specially designed probe shieldedfrom solar radiation. A flush bulb configuration is subjected to both air temperature and skintemperature and is, therefore, less accurate than a probe type sensor.

In the type of sensor shown above the probe protrudes through a hole in the aeroplane skin withthe orifice facing forward into the airflow. Air enters the probe and comes to rest where a sensingelement forms one leg of a Wheatstone bridge. The air flows out from the probe through the spillports allowing a limited rate of change of air measured at the element.

METER

R1

R2 R3

R4

WHEATSTONE BRIDGE

BASIC CIRCUIT

(1)

METER

R1

R2 R3

R4

CIRCUIT FOR MK. 1

AND MK. 1A THERMOMETERS

(2)

TEMPERATURESENSITIVE

RESISTANCE

-70 30AIR

6040 20 0

20

INDICATOR F ANDOR MK. 1

MK. 2 THERMOMETERS

(3)

OUTLETRING

HOUSING

SPILL

PORTS INLETVENTURI

C A


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Air Temperature Measurement Chapter 1

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Sometimes known as a total temperature head, this probe is less accurate than the total airtemperature probe described below and is usually only fit to simpler and or slower aircraft whereRAM rise is limited. The ability to sense RAM rise accurately is known as the recovery factor, andthis type of probe has typical values of between 0.75 and 0.95.

TOTAL AIR TEMPERATURE PROBEFor aeroplanes operating at high Mach numbers, it is usual to sense and measure the maximumtemperature rise possible, which is Total Air Temperature (TAT) if the recovery factor is 1, andRam Air Temperature (RAT) if the recovery factor is less than 1. TAT or RAT is the temperatureof the air when it is brought to rest (or nearly so) without the addition or removal of heat. TheRosemount probe shown below has a recovery factor of virtually 1, and is, therefore, known as aTAT probe, and is commonly used on transport-category aeroplanes.

AIR FLOW

AIR SCOOP

DE-ICING

HEATERS

SENSING

ELEMENT

CENTRE BODY

AIRCRAFT SKIN

TWO CONCENTRIC

PLATINUM TUBES

RADIATION

SHIELD

LOCKING SCREW

CEMENT

5-POLE

CONNECTOR

AIRFLOW

The advantages of this type of thermometer over the flush bulb type are that it has a virtually zerotime lag, and also has a recovery factor of approximately 1. This type of probe is normallyconnected directly to a flight deck indicator, and also to the Mach number module of an Air DataComputer (ADC).


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Instrumentation1-6

An air intake, which is mounted on top of a small streamlined strut, is secured to the aeroplaneskin at a predetermined location around the nose, where it is free from any boundary layeractivity. Air flows through the probe and over the sensing elements before it is expelled through avent at the back of the strut, which allows the probe to continuously sample new air. Separation ofwater droplets from the air is achieved by causing the air to turn through 90° before it passes overthe sensing element. Boundary layer air is drawn off by bleed holes in the casing. This layer of airis due to the pressure differential which exists across the casing. A pure platinum resistance wire,which is sealed within two concentric platinum tubes, is used to sense the temperature, and aheating element is mounted on the probe to prevent any ice forming. The heater has a minimaleffect on the indicated temperature readings, with typical values of 0.9°C at Mach 0.1 and 0.15°Cat Mach 1.0.


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Instrumentation 2-1

INTRODUCTIONThe pitot and static systems on an aeroplane measure the total pressures created by the forwardmotion of the aeroplane, and the static pressure surrounding the airframe. These pressures arefed to instruments, which convert the pressure differentials into speed, altitude, and rate ofchange of altitude. The system is alternatively referred to as a manometric or air data system.

PITOT TUBE

The Pitot tube (pitot probe) senses the total or pitot pressure, which is the combined static anddynamic pressure of the airflow. The tube is fitted to the airframe with its opening facing directlyinto the airflow, and the airflow comes to rest (i.e. stagnates) inside the tube entrance.

R

E

L

A

Y

HEATERFAIL

Drain Hole

PITOTHEATERSWITCH

PITOT HEAD HEATER

Dynamic +Static Pressure

A pinhole drain allows any moisture to leak away to atmosphere without significantly affecting thesensed pressure. Because moisture can accumulate within the pipeline due to condensation,drain traps are positioned at various intervals throughout the pipe work of the aircraft, usually atlow points along certain pipe runs. These drain traps contain any accumulation of water in a bowlwhich can be released by operating a spring loaded plunger on the underside of the bowl. Afteroperations of these drain traps, the integrity of the pitot system requires verification by carryingout a leak test on the system. Therefore, drain traps are only operated by ground techniciansduring maintenance.

The probe is mounted on a part of the aeroplane where there is minimal disturbance to theairflow, and is designed to extend well forward into the airflow. These probes are typicallymounted close to the nose, at the wing tips, on a pylon extending well below the wing, or at the

top of the fin. The probe is also fitted with a heater, which is powered from the aeroplaneelectrical supply (usually 28 Volt DC or 115 Volt AC), and is switched on as required by the flightdeck crew to prevent the formation of ice. An indicator light gives the operative state of thesystem. Some types show an amber light when switched OFF, or alternatively with the systemswitched ON and the heating element failed. Most transport category aeroplanes have at leasttwo pitot tubes.


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Chapter 2 Pilot-Static System

Instrumentation2-2

STATIC SOURCEThe ambient pressure of the air mass surrounding the aeroplane, or static pressure, is obtainedvia a static source. The static source, or static vent, senses the static pressure of theatmosphere, which is unaffected by the airflow. To achieve this, the source (vent) is located on apart of the aeroplane where the airflow is undisturbed by its passage, and is positioned with itsentrance perpendicular to the airflow. The vent is manufactured and attached to the surface of the

aeroplane so that it does not create local disturbances in the airflow. A typical design is shownbelow.

Vent pipe connections are installed with a slight downward angle to ensure adequate drainage,and as with the pitot system, drain traps are provided to contain any water condensed into thesystem. It is important that the vent plates are not painted as this would impair their thermalefficiency and a placard is often placed next to the static vent saying “do not paint”. The directionof the airflow around the static vent may vary as the airspeed and configuration of the aeroplanechanges, and may induce errors known as position (or pressure) errors. Minimisation of these

errors is achieved by carefully positioning the static vent, or by using multiple vents to averageout the errors. This is known as static balancing, and is achieved by fitting vents on either sideof the aeroplane fuselage. The purpose of this is to even out any differences of pressure that arecaused by the sideways motion of the static vents, which occurs during a yaw or sideslipcondition. Any residual position (pressure) errors are recorded during initial flight tests and acorrection table is produced, for various airspeeds and configurations. These readings areincorporated into the Aeroplane Operating Manual (AOM).

If failure of the primary pitot/static pressure source should occur, for example icing up of a pitot orpressure head due to a failed heater circuit, introduction of errors may occur in the instrumentreadings and other areas dependent on such pressure. The installation of a standby system insome aeroplanes acts as a safeguard against partial failure, whereby static pressure and/or pitotpressure from alternate sources is usually selected and connected into the primary system. Ablockage of the pitot source only affects the ASI. A blockage of the static source affects all of theinstruments, and it is thus common practice to provide an alternate static supply.


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Pilot-Static System Chapter 2

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ALTERNATE STATIC SOURCE

The changeover to an alternate static source is normally achieved by selector valves located inthe static lines, which are located on the flight deck, within easy reach of the flight crew. A typicalinternal alternate static source installation is shown below. Such a system only operatessatisfactorily if the cabin is unpressurised and the air within the cabin is relatively undisturbed.When calibrating the pressure/position errors of the alternate system, the manufacturer lays down

the conditions required in respect of the position of such items as windows, heating/ventilation,and doors, all of which must be observed if the system is to work correctly.


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Chapter 2 Pilot-Static System

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Moderate or large aeroplanes normally have a minimum of two separate static systems, and apair of balanced static vents, as shown below, feeds each.

The second pair of static vents is normally referred to as the auxiliary static ports, whose preciselocation is determined during prototype development.

COMBINED PITOT-STATIC (PRESSURE) HEADIn some light aeroplanes the complication and expense of separate pitot head(s) and staticsources is often avoided by incorporating both functions into a combined pressure head

022 Instrumentation

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