Common Gyroscopic Instruments .............................10-56 Vacuum-Driven Attitude Gyros .............................10-56 Electric Attitude Indicators ....................................10-58 Gyroscopic Direction Indicator or Directional  Gyro (DG) ..............................................................10-58 Turn Coordinators ..................................................10-59 Turn-and-Slip Indicator..........................................10-59 Autopilot Systems......................................................10-61 Basis for Autopilot Operation ................................10-61 Autopilot Components ...............................................10-62 Sensing Elements ...................................................10-62 Computer and Amplifier ........................................10-62 Output Elements .....................................................10-63 Command Elements ...............................................10-64 Feedback or Follow-up Element ............................10-64 Autopilot Functions................................................10-65 Yaw Dampening.....................................................10-66 Automatic Flight Control System (AFCS) ................10-66 Flight Director Systems .............................................10-66 Electronic Instruments ...............................................10-68 Electronic Attitude Director Indicator (EADI) ......10-68 Electronic Horizontal Situation Indicators  (EHSI) ....................................................................10-69 Electronic Flight Information Systems ......................10-69 Electronic Flight Instrument System (EFIS) ..........10-70 Electronic Centralized Aircraft Monitor  (ECAM) ..............................................................10-71 Engine Indicating and Crew Alerting System  (EICAS)..................................................................10-72 Flight Management System (FMS)............................10-74 Warnings and Cautions ..............................................10-75 Annunciator Systems..............................................10-75 Aural Warning Systems..........................................10-77 Clocks ........................................................................10-77 Instrument Housings and Handling ...........................10-78 Instrument Installations and Markings.......................10-80 Instrument Panels ...................................................10-80 Instrument Mounting..............................................10-81 Instrument Power Requirements ............................10-82 Instrument Range Markings ...................................10-82 Maintenance of Instruments and Instrument  Systems ......................................................................10-83 Altimeter Tests .......................................................10-83 Pitot-Static System Maintenance and Tests ...........10-84 Tachometer Maintenance .......................................10-85 Magnetic Compass Maintenance and  Compensation.........................................................10-85 Vacuum System Maintenance ................................10-86 Autopilot System Maintenance ..............................10-86 LCD Display Screens .............................................10-87 Communication and Navigation.......................11-1 Introduction..................................................................11-1 Avionics in Aviation Maintenance...........................11-2 History of Avionics ..................................................11-2 Fundamentals of Electronics........................................11-3 Analog Versus Digital Electronics ...........................11-3 Noise .....................................................................11-4 Analog Electronics ...................................................11-4 Electron Control Valves .......................................11-4 Basic Analog Circuits .........................................11-19 Digital Electronics ..............................................11-26 Radio Communication ...............................................11-30 Radio Waves...........................................................11-31 Types of Radio Waves........................................11-32 Loading Information onto a Radio Wave...............11-34 Amplitude Modulation (AM) .............................11-35 Frequency Modulation (FM) ..............................11-36 Single Side Band (SSB)......................................11-36 Radio Transmitters and Receivers..........................11-37 Transmitters ........................................................11-37 Receivers.............................................................11-37 Transceivers........................................................11-38 Antennas.................................................................11-38 Length .................................................................11-38 Polarization, Directivity, and Field Pattern ........11-39 Types...................................................................11-40 Transmission Lines.............................................11-42 Radio Navigation .......................................................11-42 VOR Navigation System ........................................11-43 Automatic Direction Finder (ADF)........................11-46 Radio Magnetic Indicator (RMI)............................11-49 Instrument Landing Systems (ILS) ........................11-49 Localizer .............................................................11-49 Glideslope ...........................................................11-50 Compass Locators...............................................11-51 Marker Beacons ..................................................11-52 Distance Measuring Equipment (DME).................11-52 Area Navigation (RNAV) ......................................11-54 Radar Beacon Transponder ....................................11-54 Transponder Tests and Inspections.....................11-56 Altitude Encoders ...............................................11-58 Collision Avoidance Systems.................................11-58 Traffic Collision Avoidance Systems (TCAS) ...11-58 ADS-B ................................................................11-60 Radio Altimeter ......................................................11-62 Weather Radar........................................................11-62 Chapter 11 XVI