These materials are to be used only for the purpose of individual, private study and may not 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 of Jeppesen. Copyright in all materials bound within these covers or attached hereto, excluding that material which is used with the permission of third parties and acknowledged as such, belongs exclusively to Jeppesen. Certain copyright material is reproduced with the permission of the International Civil Aviation Organisation, 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 Air Transport Pilot Licence (ATPL) course in preparation for the JAA ATPL theoretical knowledge examinations. Nothing in the content of this book is to be interpreted as constituting instruction or advice relating to practical flying. Whilst every effort has been made to ensure the accuracy of the information contained within this book, neither Jeppesen nor Atlantic Flight Training gives any warranty as to its accuracy or otherwise. Students preparing for the JAA ATPL theoretical knowledge examinations should not regard this book as a substitute for the JAA ATPL theoretical knowledge training syllabus published 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 a JAA ATPL theoretical knowledge training programme. No student should prepare for, or is entitled to enter himself/herself for, the JAA ATPL theoretical knowledge examinations without first being enrolled in a training school which has been granted approval by a JAA-authorised national aviation authority to deliver JAA ATPL training.

Contact Details: Sales and Service Department Jeppesen GmbH Frankfurter Strasse 233 63263 Neu-Isenburg Germany Tel: ++49 (0)6102 5070 E-mail: fra-services@jeppesen.com For further information on products and services from Jeppesen, visit our web site at: www.jeppesen.com

JA310107-000

Jeppesen Sanderson Inc., 2004 All Rights Reserved 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 have adopted 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 in content and scope to the JAA curriculum, individuals who wish to train for JAA licences need access to study materials which have been specifically designed to meet the requirements of the JAA licensing system. The volumes in this series aim to cover the subject matter tested in the JAA ATPL ground examinations as set forth in the ATPL training syllabus, contained in the JAA publication, JAR-FCL 1 (Aeroplanes). The JAA regulations specify that all those who wish to obtain a JAA ATPL must study with a flying training organisation (FTO) which has been granted approval by a JAA-authorised national aviation authority to deliver JAA ATPL training. While the formal responsibility to prepare you for both the skill tests and the ground examinations lies with the FTO, these Jeppesen manuals will provide a comprehensive and necessary background for your formal training. Jeppesen is acknowledged as the world's leading supplier of flight information services, and provides 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 base all US airlines and the majority of international airlines worldwide. It also serves the large general and business aviation markets. These manuals enable you to draw on Jeppesens vast experience as an acknowledged expert in the development and publication of pilot training materials. We at Jeppesen wish you success in your flying and training, and we are confident that your study 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 SeriesMeteorology (JAR Ref 050) The Atmosphere Wind Thermodynamics Clouds and Fog Precipitation Air Masses and Fronts Pressure System Climatology Flight Hazards Meteorological Information

General Navigation (JAR Ref 061) Basics of Navigation Magnetism Compasses Charts Dead Reckoning Navigation In-Flight Navigation Inertial Navigation Systems

Radio Navigation (JAR Ref 062) Radio Aids Self-contained and External-Referenced Navigation Systems Basic Radar Principles Area Navigation Systems Basic Radio Propagation Theory

Airframes and Systems (JAR Ref 021 01) Fuselage Windows Wings Stabilising Surfaces Landing Gear Flight Controls Hydraulics Pneumatic Systems Air Conditioning System Pressurisation De-Ice / Anti-Ice Systems Fuel Systems

Powerplant (JAR Ref 021 03) Piston Engine Turbine Engine Engine Construction Engine Systems Auxiliary Power Unit (APU)

Electrics (JAR Ref 021 02) Direct Current Alternating Current Batteries Magnetism Generator / Alternator Semiconductors Circuits

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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 Aerofoil Airflow Aeroplane Airflow Lift Coefficient Total Drag Ground Effect Stall CLMAX Augmentation Lift Coefficient and Speed Boundary Layer High Speed Flight Stability Flying Controls Adverse Weather Conditions Propellers Operating Limitations Flight Mechanics

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 Flights ICAO ATC Flight Planning IFR (Airways) Flight Planning Jeppesen Airway Manual Meteorological Messages Point of Equal Time Point of Safe Return Medium Range Jet Transport Planning

Air Law (JAR Ref 010) International Agreements and Organisations Annex 8 Airworthiness of Aircraft Annex 7 Aircraft Nationality and Registration Marks Annex 1 Licensing Rules of the Air Procedures for Air Navigation Air Traffic Services Aerodromes Facilitation Search and Rescue Security Aircraft Accident Investigation JAR-FCL National Law

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Human Performance and Limitations (JAR Ref 040) Human Factors Aviation Physiology and Health Maintenance Aviation Psychology

Operational Procedures (JAR Ref 070) Operator Air Operations Certificate Flight Operations Aerodrome Operating Minima Low Visibility Operations Special Operational Procedures and Hazards Transoceanic and Polar Flight

Communications (JAR Ref 090) Definitions General Operation Procedures Relevant Weather Information Communication Failure VHF Propagation Allocation of Frequencies Distress and Urgency Procedures Aerodrome Control Approach Control Area Control

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Table of Contents

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

CHAPTER 2Pitot-Static System Introduction ...................................................................................................................................................2-1 Pitot Tube......................................................................................................................................................2-1 Static Source.................................................................................................................................................2-2 Alternate Static Source .................................................................................................................................2-3 Combined Pitot-Static (Pressure) Head ........................................................................................................2-4 Operating Problems ......................................................................................................................................2-5 Pitot/Static System Errors .............................................................................................................................2-6

CHAPTER 3Pressure Altimeter Introduction ...................................................................................................................................................3-1 Pressure Altitude...........................................................................................................................................3-2 Density Altitude .............................................................................................................................................3-2 The Simple Altimeter.....................................................................................................................................3-2 Datum Sub-Scale Settings ............................................................................................................................3-3 The Sensitive Altimeter .................................................................................................................................3-4 Altimeter Displays .........................................................................................................................................3-4 Design Errors ................................................................................................................................................3-7 Errors due to Calibration ...............................................................................................................................3-7 Blockages and Leakages ..............................................................................................................................3-9 Servo Altimeters............................................................................................................................................3-9 Operation of a Servo-Altimeter....................................................................................................................3-10 Servo-Altimeter Power Failure ....................................................................................................................3-11 Altitude Encoding ........................................................................................................................................3-11 Advantages of Servo-Altimeters..................................................................................................................3-11

CHAPTER 4Vertical Speed Indicator Introduction ...................................................................................................................................................4-1 Principle of Operation ...................................................................................................................................4-1 Operation of the VSI .....................................................................................................................................4-2 Errors of the VSI ...........................................................................................................................................4-2 Lag................................................................................................................................................................4-2 Instrument Error ............................................................................................................................................4-2 Manoeuvre Induced Error .............................................................................................................................4-2 Faults of the VSI ...........................................................................................................................................4-2 Blockages .....................................................................................................................................................4-2 Breakage or leakage in the Static Line .........................................................................................................4-2 Instantaneous Vertical Speed Indicator (IVSI) ..............................................................................................4-2 Operation of the IVSI / ILVSI.........................................................................................................................4-3

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CHAPTER 5Airspeed Indicator Introduction .................................................................................................................................................. 5-1 Principle of the Airspeed Indicator (ASI) ...................................................................................................... 5-1 Operation of a Simple ASI............................................................................................................................ 5-1 Sensitive and Servo Airspeed Indicators...................................................................................................... 5-1 Calibration of the ASI ................................................................................................................................... 5-2 Colour Coding of the ASI ............................................................................................................................. 5-2 ASI Errors .................................................................................................................................................... 5-3 ASI Faults .................................................................................................................................................... 5-5 Calculation of CAS to TAS (up to 300 knots) ............................................................................................... 5-6

CHAPTER 6Machmeter Introduction .................................................................................................................................................. 6-1 Critical Mach Number (Mcrit) ......................................................................................................................... 6-1 Principle of Operation................................................................................................................................... 6-2 Machmeter Construction and Operation ...................................................................................................... 6-4 Calibration .................................................................................................................................................... 6-4 Errors ........................................................................................................................................................... 6-5 Blockages and Leakages ............................................................................................................................. 6-5 Accuracy ...................................................................................................................................................... 6-5 Serviceability Checks ................................................................................................................................... 6-5

CHAPTER 7Mach Airspeed Indicator Introduction .................................................................................................................................................. 7-1 Display ......................................................................................................................................................... 7-1 VMO Pointer .................................................................................................................................................. 7-1 Driven Cursor ............................................................................................................................................... 7-2 Bugs............................................................................................................................................................. 7-2 Linkages....................................................................................................................................................... 7-2 Errors ........................................................................................................................................................... 7-2

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

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CHAPTER 9Basic Magnetism Introduction ...................................................................................................................................................9-1 Magnetic Properties ......................................................................................................................................9-1 Fundamental Laws of Magnetism .................................................................................................................9-3 Characteristics of Lines of Magnetic Flux .....................................................................................................9-4 Magnetic Materials........................................................................................................................................9-5 Ferromagnetic...............................................................................................................................................9-5 Paramagnetic................................................................................................................................................9-5 Diamagnetic ..................................................................................................................................................9-5 Permeability ..................................................................................................................................................9-6 Electromagnetism .........................................................................................................................................9-6 An Electromagnet .........................................................................................................................................9-7 Magnetic Moments........................................................................................................................................9-8 Period of Oscillation of a Suspended Magnet ...............................................................................................9-8

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

CHAPTER 11Aeroplane Magnetism Introduction .................................................................................................................................................11-1 Types of Aeroplane Magnetism ..................................................................................................................11-1 Components of Hard Iron Magnetism .........................................................................................................11-2 Components of Soft Iron Magnetism...........................................................................................................11-5 Determination of Deviation Coefficients ......................................................................................................11-6 Minimum Deviation .....................................................................................................................................11-7 Maximum Deviation ....................................................................................................................................11-7 Joint Airworthiness Requirements (JAR) Limits ..........................................................................................11-8 Compass Swinging .....................................................................................................................................11-9 The Compass Swing Procedure .................................................................................................................11-9 An Example of a Compass Swing.............................................................................................................11-10 Deviation Compensation Devices .............................................................................................................11-11

CHAPTER 12Direct Reading Magnetic Compass Introduction .................................................................................................................................................12-1 Properties of a Direct Reading Compass ....................................................................................................12-2 E Type Compass.......................................................................................................................................12-3 Pre-flight Checks.........................................................................................................................................12-4 Principle of a Pendulum ..............................................................................................................................12-4 Acceleration Errors .....................................................................................................................................12-4 Turning Errors .............................................................................................................................................12-7

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CHAPTER 13Remote Indicating Compass Introduction ................................................................................................................................................ 13-1 RIC Architecture......................................................................................................................................... 13-1 Principle of a Flux Detector Element .......................................................................................................... 13-1 Flux Detector Unit ...................................................................................................................................... 13-4 Operation of the Remote Indicating Compass System............................................................................... 13-5 Gyroscope Element.................................................................................................................................... 13-8 Heading Indicator ....................................................................................................................................... 13-8 Modes of Operation.................................................................................................................................... 13-9 Synchronising Indicators ............................................................................................................................ 13-9 Manual Synchronisation........................................................................................................................... 13-10 Operation of an RIC in a Turn .................................................................................................................. 13-10 Advantages of a Remote Indicating Gyro Magnetic Compass ................................................................. 13-11 Disadvantages of the Remote Indicating Gyro Magnetic Compass ......................................................... 13-11

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

CHAPTER 15Direction Indicator Introduction ................................................................................................................................................ 15-1 Basic Description of the Direction Indicator................................................................................................ 15-1 Operation of the Direction Indicator............................................................................................................ 15-2 Errors Associated with the Air Driven Direction Indicator ........................................................................... 15-4 Use of the Direction Indicator (DI) .............................................................................................................. 15-4 Advanced Use of the Direction Indicator .................................................................................................... 15-4 Sample Calculation .................................................................................................................................... 15-5

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

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

CHAPTER 18Turn Co-ordinator Introduction .................................................................................................................................................18-1 Principle of Operation .................................................................................................................................18-2

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CHAPTER 19Inertial Navigation System Introduction ................................................................................................................................................ 19-1 The Principle and Construction of an Accelerometer ................................................................................. 19-1 Performance .............................................................................................................................................. 19-3 Operation of a Gyro-Stabilised Platform..................................................................................................... 19-3 Setting-up Procedures ............................................................................................................................... 19-6 Levelling..................................................................................................................................................... 19-6 Alignment ................................................................................................................................................... 19-7 Levelling and Alignment ............................................................................................................................. 19-7 Corrections................................................................................................................................................. 19-7 Coriolis ....................................................................................................................................................... 19-8 Centripetal Acceleration ............................................................................................................................. 19-8 Wander Azimuth System............................................................................................................................ 19-9 The Schuler Tuned Platform ...................................................................................................................... 19-9 Errors ....................................................................................................................................................... 19-11 The Advantages and Disadvantages of an INS........................................................................................ 19-12 Mode Selector Panel................................................................................................................................ 19-13 Control Display Unit ................................................................................................................................. 19-14

CHAPTER 20Inertial Reference System Introduction ................................................................................................................................................ 20-1 Description of the Strap-Down System ...................................................................................................... 20-1 Solid State Gyros ....................................................................................................................................... 20-2 Ring Laser Gyro ......................................................................................................................................... 20-2 Fibre Optic Gyro......................................................................................................................................... 20-3 Advantages and Disadvantages of RLGs .................................................................................................. 20-3 Alignment of the Inertial Reference System ............................................................................................... 20-4 Performance .............................................................................................................................................. 20-4 The Control, Display, and Output from an IRS ........................................................................................... 20-4 Description of a Typical IRS ....................................................................................................................... 20-5 IRS Transfer Switch ................................................................................................................................... 20-7 IRS Alignment ............................................................................................................................................ 20-7 Loss of Alignment in Flight ......................................................................................................................... 20-7

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

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CHAPTER 22Electronic Flight Instrument System Introduction .................................................................................................................................................22-1 EFIS Architecture........................................................................................................................................22-1 Symbol Generator (SG) ..............................................................................................................................22-2 Instrument Comparator Unit (ICU) ..............................................................................................................22-2 Compression Mode.....................................................................................................................................22-2 Temperature Sensing Units ........................................................................................................................22-3 Mode Control Panels (MCP) .......................................................................................................................22-3 Light Sensors ..............................................................................................................................................22-3 Attitude Director Indicator (ADI) ..................................................................................................................22-3 Radio Altitude..............................................................................................................................................22-5 Decision Height...........................................................................................................................................22-5 Localiser and Glide Slope Indication...........................................................................................................22-5 The Horizontal Situation Indicator (HSI)......................................................................................................22-5 Plan Mode...................................................................................................................................................22-8 VOR and ILS Modes ...................................................................................................................................22-8 EFIS/IRS Interface ....................................................................................................................................22-10 Heading Reference Switch........................................................................................................................22-11 HSI Symbology .........................................................................................................................................22-11

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

CHAPTER 24Flight Director System Introduction .................................................................................................................................................24-1 Flight Director Architecture..........................................................................................................................24-1 Flight Director Control Inputs ......................................................................................................................24-3 The Flight Director Computer (FDC) ...........................................................................................................24-4 Mode Control Unit .......................................................................................................................................24-4 Flight Director Displays ...............................................................................................................................24-4 Flight Director Modes of Operation .............................................................................................................24-6 Attitude Mode..............................................................................................................................................24-6 Heading ......................................................................................................................................................24-7 Altitude Hold................................................................................................................................................24-9 Localiser/VOR (LOC/VOR) .........................................................................................................................24-9 Glideslope (GS) ........................................................................................................................................24-11 Go-Around (GA)........................................................................................................................................24-12 Mode Annunciator.....................................................................................................................................24-12 Operation of the Attitude Director Indicator ...............................................................................................24-12 The Horizontal Situation Indicator (HSI) Flight Director Commands .........................................................24-14

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CHAPTER 25Automatic Flight Control System Introduction ................................................................................................................................................ 25-1 Stability and Control Augmentation ............................................................................................................ 25-1 Attitude Hold .............................................................................................................................................. 25-1 Flight Control.............................................................................................................................................. 25-1 Classification of an AFCS .......................................................................................................................... 25-2 Control Channels ....................................................................................................................................... 25-2 Inner Loop Control (Stabilisation)............................................................................................................... 25-2 Operation of an Inner Loop Pitch Stabilisation System .............................................................................. 25-3 Outer Loop Control..................................................................................................................................... 25-4 Roll Modes ................................................................................................................................................. 25-5 Pitch Modes ............................................................................................................................................... 25-7 Combined Roll and Pitch Modes ................................................................................................................ 25-8 Attitude Sensing ......................................................................................................................................... 25-9 The AFCS Computer (Signal Processor) ................................................................................................. 25-10 Servomotor Actuators .............................................................................................................................. 25-11 Autopilot Terminology .............................................................................................................................. 25-12 Cross Coupling......................................................................................................................................... 25-14 ILS Coupling ............................................................................................................................................ 25-14 VOR Coupling .......................................................................................................................................... 25-15 Stability Problems .................................................................................................................................... 25-16 Yaw Damper ............................................................................................................................................ 25-16 Mach Trim System ................................................................................................................................... 25-17 Automatic Pitch Trim Control ................................................................................................................... 25-18 Interlocks.................................................................................................................................................. 25-20 Synchronisation........................................................................................................................................ 25-20 Instinctive Cut Out.................................................................................................................................... 25-20

CHAPTER 26Automatic Landing System Introduction ................................................................................................................................................ 26-1 Basic 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 .................................................................................. 26-4 Weather Minima ......................................................................................................................................... 26-5 ICAO Categorisation for Low Visibility Landing Capabilities ...................................................................... 26-5 The Fundamental Landing Requirement.................................................................................................... 26-6 System Reliability and Integrity .................................................................................................................. 26-7

CHAPTER 27Thrust Management Systems Introduction ................................................................................................................................................ 27-1 Determining the Thrust Required ............................................................................................................... 27-1 Calculation of Climb and Cruise Thrust...................................................................................................... 27-2 Cruising Methods ....................................................................................................................................... 27-3 Electronic Engine Control (EEC) ................................................................................................................ 27-3 Full Authority Digital Engine Control (FADEC) ........................................................................................... 27-3 Autothrottle (A/T)........................................................................................................................................ 27-6 Thrust Lever Operation .............................................................................................................................. 27-7 Thrust Management via the Autothrottle .................................................................................................... 27-7 Thrust Management Computer (TMC) ....................................................................................................... 27-8 Thrust Mode Select Panel (TMSP)............................................................................................................. 27-8

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CHAPTER 28Central Warning System Introduction .................................................................................................................................................28-1 Central Warning System Annunciator Panel ...............................................................................................28-1 Aural Warnings ...........................................................................................................................................28-2

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

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

CHAPTER 31Traffic Collision Avoidance System Introduction .................................................................................................................................................31-1 TCAS I ........................................................................................................................................................31-1 TCAS II .......................................................................................................................................................31-1 TCAS III ......................................................................................................................................................31-1 Aeroplane Installation .................................................................................................................................31-2 Operation of TCAS II...................................................................................................................................31-4 TCAS Aural Warnings .................................................................................................................................31-4 Information Display .....................................................................................................................................31-5 Resolution Advisory / Vertical Speed Indicator (RA / VSI) ..........................................................................31-7 TCAS Control Panel....................................................................................................................................31-8 Operating Restrictions ................................................................................................................................31-8

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CHAPTER 32Mach/Airspeed Warning System Introduction ................................................................................................................................................ 32-1 System Architecture and Operation ........................................................................................................... 32-1 Maximum Operating Airspeed Schedule.................................................................................................... 32-2

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

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

CHAPTER 35General Engine Instrumentation Introduction ................................................................................................................................................ 35-1 Piston Engines ........................................................................................................................................... 35-1 Turbo Propeller Engines ............................................................................................................................ 35-2 Gas Turbine Engines ................................................................................................................................. 35-2

CHAPTER 36Pressure and Temperature Sensors Introduction ................................................................................................................................................ 36-1 Pressure Measurement.............................................................................................................................. 36-1 Temperature Measurement........................................................................................................................ 36-3

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

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

CHAPTER 39Engine Torque Measurement Introduction .................................................................................................................................................39-1 Torque Meter ..............................................................................................................................................39-1 Negative Torque Sensing ...........................................................................................................................39-3

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

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

CHAPTER 42EICAS Introduction .................................................................................................................................................42-1 EICAS Architecture .....................................................................................................................................42-1 Engine Displays ..........................................................................................................................................42-2 Crew Alerting ..............................................................................................................................................42-3 Warnings (Level A) .....................................................................................................................................42-3 Cautions (Level B) ......................................................................................................................................42-4 Advisories (Level C) ....................................................................................................................................42-4 Master Warning/Caution Light.....................................................................................................................42-4 Inhibits ........................................................................................................................................................42-4 Display Messages.......................................................................................................................................42-4 Status..........................................................................................................................................................42-6 Maintenance ...............................................................................................................................................42-7 EICAS Failure Modes .................................................................................................................................42-7

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CHAPTER 43ECAM Introduction ................................................................................................................................................ 43-1 Engine / Warning (E/W) CRT Display ........................................................................................................ 43-2 The System / Status (S/S) CRT Display..................................................................................................... 43-3 ECAM System Architecture........................................................................................................................ 43-3 Flight Warning Computers (FWCS)............................................................................................................ 43-4 Display management Computers (DMC) ................................................................................................... 43-4 System Data Acquisition Concentrators (SDAC)........................................................................................ 43-4 ECAM Control Panel (ECP) ....................................................................................................................... 43-4 Attention Getters ........................................................................................................................................ 43-5 ECAM System Failure................................................................................................................................ 43-6 Failure Categorisation ................................................................................................................................ 43-6 System Operation ...................................................................................................................................... 43-6

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INTRODUCTIONThe temperature of air under pure static conditions at the various flight levels is one of the basic parameters required to establish data that is vital to the performance monitoring of modern aeroplanes. The measurement of Static Air Temperature (SAT) by direct means is, however, not possible for all types of aeroplanes, because the measurement is potentially affected by adiabatic compression of the air at increased airspeeds. The boundary layer over the outer surface of an aeroplane flying below Mach 0.2 is very close to SAT, but at higher Mach numbers the boundary layer 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 the high-speed airflow. The RAM Rise is always pre-calculated and is tabulated or graphed as a function of Mach number in the Operations or Flight Manual for each type of aeroplane, a sample of which is shown below.

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Chapter 1

Air Temperature Measurement

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

( TAS kt )2 100For example, for an estimated TAS of 460 kt deduct

( 460 kt )2 100

from the indicated air

temperature, which is approximately equal to 21C. If this figure is subtracted from the Indicated Outside Air Temperature (IOAT), it gives the Corrected Outside Air Temperature (COAT), which is 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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Instrumentation

Air Temperature Measurement

Chapter 1

Alternatively written as:TM

TS =

1 + 0.2KM2

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 is dependent on whether SAT or RAT is required, and the normal operating speed of the aeroplane on 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 temperature changes.

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-speed light aeroplanes, and passes through the fuselage or canopy with the sensitive element projecting into 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 capillary tube, with the bulb mounted externally in the airflow and the capillary tube transmitting the liquid pressure to a Bourdon tube. As the temperature to which the bulb is subjected changes, the liquid expands or contracts, and causes the Bourdon tube to wind or unwind. This movement of the Bourdon 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 connected in a circuit. The Electrical (Wheatstone Bridge) Thermometer commonly uses the temperature/resistance technique.

Instrumentation

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Chapter 1

Air Temperature Measurement

TEMPERATURE SENSITIVE RESISTANCE R1 R4 METER R3 R1

R4

60

40

20

0

20

AR2

CR2

METER

-70

AIR

30

R3

WHEATSTONE BRIDGE BASIC CIRCUIT (1)

CIRCUIT FOR MK. 1 AND MK. 1A THERMOMETERS (2)

INDICATOR F ANDOR MK. 1 MK. 2 THERMOMETERS (3)

The bridge consists of four resistance arms, which connect across a low voltage source as shown above. When the system is switched on, current flows in the circuit and divides at point A before flowing 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 Bridge is balanced resistance-wise, no current flows and the moving coil galvanometer (meter) reads zero. If the temperature (resistance) of R4 changes, the bridge becomes unbalanced, and the resulting 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 probe mounted in what is termed a flush bulb configuration, or in a specially designed probe shielded from solar radiation. A flush bulb configuration is subjected to both air temperature and skin temperature and is, therefore, less accurate than a probe type sensor.

SPILL PORTS OUTLET RING HOUSING

INLET VENTURI

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

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Instrumentation

Air Temperature Measurement

Chapter 1

Sometimes known as a total temperature head, this probe is less accurate than the total air temperature probe described below and is usually only fit to simpler and or slower aircraft where RAM rise is limited. The ability to sense RAM rise accurately is known as the recovery factor, and this 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 maximum temperature rise possible, which is Total Air Temperature (TAT) if the recovery factor is 1, and Ram Air Temperature (RAT) if the recovery factor is less than 1. TAT or RAT is the temperature of the air when it is brought to rest (or nearly so) without the addition or removal of heat. The Rosemount probe shown below has a recovery factor of virtually 1, and is, therefore, known as a TAT probe, and is commonly used on transport-category aeroplanes.AIR FLOW

AIR SCOOP

TWO CONCENTRIC PLATINUM TUBES RADIATION SHIELD

AIRFLOWDE-ICING HEATERS SENSING ELEMENT

LOCKING SCREW

CENTRE BODY

AIRCRAFT SKIN

CEMENT

5-POLE CONNECTOR

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

Instrumentation

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Chapter 1

Air Temperature Measurement

An air intake, which is mounted on top of a small streamlined strut, is secured to the aeroplane skin at a predetermined location around the nose, where it is free from any boundary layer activity. Air flows through the probe and over the sensing elements before it is expelled through a vent at the back of the strut, which allows the probe to continuously sample new air. Separation of water droplets from the air is achieved by causing the air to turn through 90 before it passes over the sensing element. Boundary layer air is drawn off by bleed holes in the casing. This layer of air is 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 a heating element is mounted on the probe to prevent any ice forming. The heater has a minimal effect on the indicated temperature readings, with typical values of 0.9C at Mach 0.1 and 0.15C at Mach 1.0.

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Instrumentation

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

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

R E L A Y

HEATER FAIL

PITOT HEATER SWITCH Drain Hole PITOT HEAD HEATER

Dynamic + Static Pressure

A pinhole drain allows any moisture to leak away to atmosphere without significantly affecting the sensed 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 at low points along certain pipe runs. These drain traps contain any accumulation of water in a bowl which can be released by operating a spring loaded plunger on the underside of the bowl. After operations of these drain traps, the integrity of the pitot system requires verification by carrying out a leak test on the system. Therefore, drain traps are only operated by ground technicians during maintenance. The probe is mounted on a part of the aeroplane where there is minimal disturbance to the airflow, and is designed to extend well forward into the airflow. These probes are typically mounted 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 aeroplane electrical supply (usually 28 Volt DC or 115 Volt AC), and is switched on as required by the flight deck crew to prevent the formation of ice. An indicator light gives the operative state of the system. Some types show an amber light when switched OFF, or alternatively with the system switched ON and the heating element failed. Most transport category aeroplanes have at least two pitot tubes.

Instrumentation

2-1

Chapter 2

Pilot-Static System

STATIC SOURCEThe ambient pressure of the air mass surrounding the aeroplane, or static pressure, is obtained via a static source. The static source, or static vent, senses the static pressure of the atmosphere, which is unaffected by the airflow. To achieve this, the source (vent) is located on a part of the aeroplane where the airflow is undisturbed by its passage, and is positioned with its entrance 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 shown below.

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 the system. It is important that the vent plates are not painted as this would impair their thermal efficiency and a placard is often placed next to the static vent saying do not paint. The direction of the airflow around the static vent may vary as the airspeed and configuration of the aeroplane changes, 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 average out the errors. This is known as static balancing, and is achieved by fitting vents on either side of the aeroplane fuselage. The purpose of this is to even out any differences of pressure that are caused by the sideways motion of the static vents, which occurs during a yaw or sideslip condition. Any residual position (pressure) errors are recorded during initial flight tests and a correction table is produced, for various airspeeds and configurations. These readings are incorporated into the Aeroplane Operating Manual (AOM). If failure of the primary pitot/static pressure source should occur, for example icing up of a pitot or pressure head due to a failed heater circuit, introduction of errors may occur in the instrument readings and other areas dependent on such pressure. The installation of a standby system in some aeroplanes acts as a safeguard against partial failure, whereby static pressure and/or pitot pressure from alternate sources is usually selected and connected into the primary system. A blockage of the pitot source only affects the ASI. A blockage of the static source affects all of the instruments, and it is thus common practice to provide an alternate static supply.

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Instrumentation

Pilot-Static System

Chapter 2

ALTERNATE STATIC SOURCEThe changeover to an alternate static source is normally achieved by selector valves located in the static lines, which are located on the flight deck, within easy reach of the flight crew. A typical internal alternate static source installation is shown below. Such a system only operates satisfactorily 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.

Instrumentation

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Chapter 2

Pilot-Static System

Moderate or large aeroplanes normally have a minimum of two separate static systems, and a pair 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 precise location is determined during prototype development.

COMBINED PITOT-STATIC (PRESSURE) HEADIn some light aeroplanes the complication and expense of separate pitot head(s) and static sources is often avoided by incorporating both functions into a combined pressure head. The combined head is usually mounted on a pylon below the wing toward the tip, thus reducing the position/pressure error to an acceptable level although accuracy is well below the standards achieved by systems that are more sophisticated. A typical combined pressure head is in the following illustration.

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Instrumentation

Pilot-Static System

Chapter 2

Static pressure is admitted to the pressure head through slots or holes cut into the static casing at 90 to the airflow, whilst pitot pressure enters the head via the pitot input port that faces directly into the airflow. The different pressures are fed to the flight instruments via separate, seamless, and corrosion-resistant metal pipelines. An electric heating element is also connected to the aeroplane electrical supply to prevent ice forming inside the pressure head, which may obstruct the airflow. This sensor is particularly prone to errors during manoeuvres, when changes in pitch can result in the pitot/static sources being presented to the relative airflow in such a way that the full dynamic pressure is not sensed. More significantly, dynamic pressure effects may also intrude into the static supply.

OPERATING PROBLEMSAny ingestion of water is normally cleared by the use of drain holes, although these are unable to cope with very heavy precipitation. If the ingested water freezes, ice blocks the pressure head. It is, therefore, fitted with a heater. Checking the heaters function is part of pre-flight checks. Blockages may also occur due to the ingestion of dirt, insects, etc, although the effect of blockages is reduced if the systems are duplicated. Where water accumulates due to heavy precipitation or to condensation over a prolonged period, drain traps are incorporated into the system at various low points along the pitot static pipelines. They take the form of clear plastic bowls with a spring loaded drain plug at the bottom, which is occasionally pushed in against the spring pressure to release the accumulated water. As there is no sure way of telling if the drain plug has fully resealed, the ground engineers carry out a pitot and/or static leak test. This is not a task that the aircrew should carry out.

Instrumentation

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Chapter 2

Pilot-Static System

PITOT/STATIC SYSTEM ERRORSThe following errors may occur in pitot/static systems: Pressure (Position) error This is composed of errors due to change of configuration and aircraft manoeuvring. The errors due to change of configuration are determined during aircraft flight testing and are tabulated in the Flight Manual. Manoeuvring induced errors are random in nature and are not corrected. Changes in configuration (flaps, under-carriage, etc.) This may cause localised turbulence around the static vents and change the pressure sens