AMT110 Communica/on and Naviga/on Chapter 11 Communica/on and Naviga/on •  Skip pages 11-­‐1 through 11-­‐30 !
Will be covered AircraA Electrical Systems Basic Rules •  All equipment repairs must be made by the manufacturer or by an FAA-­‐cer/ficated repair sta/on •  To perform certain tuning opera/ons on radio transmiJers, technicians must hold the appropriate license issued by the Federal Communica/ons Commission (FCC) •  Instruments, such as transponders, have encoded IDs. When installing, record S/N and ID’s in log books Radio Waves Fields surrounding a radio antenna. Radio Waves A radio wave has two components, an electric wave (E) and a magne/c wave (H). These waves are at right angles to each other and both are at right angles to the direc/on the wave is traveling. Basic Radio TransmiJer A block diagram of a simple radio transmiJer. Basic Radio Receiver A block diagram of a simple radio receiver. Modula/on •  A radio signal carries informa/on by varying the signal !
Modula/on is the varying of the signal •  AM – Amplitude Modula/on !
Varies the signal strength (amplitude) •  FM – Frequency Modula/on Varies the signal frequency !  Less sensi/ve to electronic noise !
•  SSB – Single-­‐Sideband (SSB) !
Method to reduce bandwidth requirements AM – Amplitude Modula/on Amplitude modula/on. FM – Frequency Modula/on Frequency modula/on. SSB – Single-­‐Sideband Advantage of SSB over AM. Radio Wavelength Radio Wavelength Radio Wavelength •  Radio waves travel at approximately the speed of light •  The wavelength is the distance from one peak to the next peak •  The wavelength is inversely propor/onal to the frequency !
The higher the frequency, the shorter the wave •  Antennas are design around a radio frequency’s wavelength Radio Wavelength Rela/onship between frequency and wavelength. Frequency Alloca/on Frequency alloca/on for avia/on naviga/on and communica/on. Antenna •  Transmits and receives radio waves •  You must follow direc/ons for antenna placement •  The airframe may serve as a “ground plane” Insure grounding connec/on is in perfect condi/on !  Corrosion can form an insulator !
•  Must be installed so that physical loads imposed are transmiJed to the aircraA structure !
Doublers on the inside of the skin are oAen used •  Recreate the structural strength of the aircraA skin Coaxial Cable Coaxial (Coax) Cable •  Connect antennas to radios •  Use exactly what the manufacturer calls for From the outside, different coax cables look the same !  Keep the length exact !
•  Follow minimum bend radius guidelines !
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Usually 10 /mes the diameter of the cable Don’t crush Coax cables should be supported every 2 feet Keep away from power lines and nav strobes Check for corrosion around connectors VOR VOR VOR Antenna VOR Antenna VOR Antenna VOR Receiver VOR -­‐ CDI VOR VOR •  Very high frequency Omnidirec/onal Range naviga/on system •  108 to 118 MHz 50 kHz channel spacing !  360 channels !
•  Airway VOR ground transmiJers 200 waJ output !  Approximately 40 -­‐ 130 nau/cal mile range !
•  Range from AIM VOR •  Terminal VOR (TVOR) Located on airport !  50 waJ output !  Approximately 25 nau/cal mile range !
•  Course Devia/on Indicator (CDI) Displays VOR informa/on !  OBS – Omni-­‐Bearing Selector !
•  Used to set dial/radial/direc/on !
To/From Indica/on •  Tells you if you are flying “ To” or “From” the transmiJer VOR •  Course Devia/on Indicator (CDI) !
“Needle” •  The needle swings leA or right indica/ng the direc/on to turn to return to course •  Opera/on: Tune in VOR sta/on on receiver !  Select radial !  Use OBS to set radial !  Fly “to” needle !
Instrument Landing System (ILS) Instrument Landing System (ILS) Instrument Landing System (ILS) The Instrument Landing System (ILS). Video
Instrument Landing System (ILS) •  Guides the pilot to the runway •  Localizer -­‐ the por/on of an instrument landing system that directs the pilot along the center line of the instrument runway. •  Glide Slope -­‐ the por/on of an instrument landing system that provides the ver/cal path along which an aircraA descends on an instrument landing. •  Uses the same “nav” receiver as the VOR. •  Adds a ver/cal (height) indicator to CDI Instrument Landing System (ILS) •  Uses the VOR antenna plus a small UHF dipole antenna for the glide slope !
Glide slope antenna is usually built into VOR antenna •  Marker Beacons Displayed on CDI or separate indicator !  Outer marker – blue !  Middle marker – amber !  Inner marker – white !
•  Being replaced by GPS Automa/c Direc/on Finder (ADF) Automa/c Direc/on Finder (ADF) Automa/c Direc/on Finder (ADF) Automa/c Direc/on Finder (ADF) •  Uses non-­‐direc/onal radio beacon LF/MF !  AM commercial broadcast sta/on !
•  Uses two antennas Loop !  Sense !  Some/me in a single unit !
•  Pilot tunes in the radio sta/on and listens to the audio signal !
Morse code or AM broadcast Automa/c Direc/on Finder (ADF) •  Indicator gives the rela/ve bearing between the aircraA and the radio sta/on 0° -­‐ Sta/on in front of the aircraA !  90° -­‐ Sta/on to the right !  180° -­‐ Sta/on behind the aircraA !  270° -­‐ Sta/on to the leA !
•  New ADFs have a movable card that shows the aircraAs magnet heading !
The needle will indicate the magne/c bearing to the sta/on DME •  Distance Measuring Equipment •  Measures distance from Tac/cal Air Naviga/on (TACAN) sta/on to aircraA •  VORTAC – VOR and TACAN in same loca/on •  Antenna is short UHF blade mounted on the belly of the aircraA •  Process DME send signal to TACAN !  TACAN repeats signal back !  The DME /mes the length of the round trip signal and calculates distance !
DME •  Measures “slant-­‐line” distance since TACAN and aircraA are at different height •  DME displays are now built into many nav/comm radios •  Being replaced by GPS RNAV •  Area Naviga/on •  Originally a computer used VOR and DME data to compute an aircraA’s posi/on and path •  Now GPS is used •  Enables a pilot to fly more direct routes than just following VOR airways Radar Beacon Transponder The control head of an ATC transponder. Radar Beacon Transponder •  Usually referred to as the “ Transponder” •  Compliments air traffic control’s ground radar The radar has a “blip” that represents an aircraA !  The transponder adds iden/fica/on informa/on to the “blip” !
•  The ground radar sends out a request and the transponder responds with the aircraA informa/on •  “Squawk” code – a 4 digit iden/fica/on code Air traffic control instructs the pilot to set the code !  Default VFR code is “1200” !
Radar Beacon Transponder •  Modes A – Iden/fies with just the “squawk” code !  C – “Squawk” code plus pressure al/tude !
•  Transponder is connected to an encoding al/meter !
S – Mode C plus built in aircraA iden/fier and advanced data transmission features •  Interroga/ons (requests) can be made to a specific aircraA •  Ground radar informa/on can be sent back to the aircraA •  IDENT buJon – air traffic control will instruct pilot to “IDENT” !
This will highlight the aircraA on the controllers radar screen TCAS •  Traffic Alert/Collision Avoidance System •  Receives other aircraA’s transponder signals •  Uses the transponder informa/on to provide traffic display and alerts TCAS I – warning only !  TCAS II – gives correc/ve ac/on instruc/ons !
•  Being supplemented/replaced by Automa/c Dependent Surveillance-­‐Broadcast (ADS-­‐B) Part of Next Genera/on Air Transporta/on System (NextGen) !  Must be installed by 01/01/2020 !
Radio (Radar) Al/meters •  Bounces a radio signal off the ground and measures the height of the aircraA •  More accurate than a pressure (pneuma/c) al/meter Terrain Awareness Warning System •  TAWS •  Also called Ground Proximity Warning System (GPWS) •  Monitors the aircraA’s configura/on and ground proximity (how close) !
al/meter; air data computer; instrument landing system; landing gear; and flap posi/ons •  Warns the pilot if there is a possible conflict Terrain Awareness Warning System •  Types !
Terrain Depic/on Systems •  Uses terrain eleva/on database and aircraA loca/on •  Doesn’t provide warnings !
Class-­‐B •  Uses terrain eleva/on database and aircraA loca/on •  Provides warnings !
Class-­‐A •  Uses terrain eleva/on database and aircraA loca/on •  Uses radio al/meter •  Uses aircraA configura/on data •  Weather Radars Detects water droplets !  Doppler radar can also detect wind shear microbursts !
•  Lightning Detector System !
Detects voltage discharges caused by storms •  Detects discharges much smaller than visible lightning !
Uses loop and sense antenna similar to a DME •  XM weather !
Ground radar weather informa/on is broadcast on the XM satellite radio system •
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ADS-­‐B Automa/c Dependent Surveillance-­‐Broadcast Video 1 Video 2 Video 3 Video 4 ADS-­‐B ADS-­‐B •  Required for by 01/01/2020 !
Requirements similar to transponder requirements •  Part of the “NextGen” system •  Will be used interna/onally •  ADS-­‐B Out !
AircraA GPS derived posi/on •  ADS-­‐B In ADS-­‐B Traffic informa/on !  Weather !  Terrain !  Flight informa/on !
•  Links !
UAT •  978 MHz •  Used under 18,000 A •  Links !
ADS-­‐B 1090 MHz Extend SquiJer •  Referred to as 1090ES •  Same frequency at transponder •  Required above 18,000 A •  Most likely the interna/onal standard ELT ELT •  Emergency Locator TransmiJer •  Self contained, baJery powered transmiJer !
BaJery provides power for at least 48 hours •  Triggered by severe impact •  121.5/243.0 MHz – older type Monitoring satellite has been deac/vated !  S/ll legal to use in USA, not interna/onally !
ELT •  406.025 MHz – new standard Ac/vely monitored by satellite !  Some include GPS locators !  Upgrade installa/on may require adding ac/va/on switch to cockpit panel !  Upgrade from 121.5 to 406 doesn’t require 337 !
•  Usually installed as far aA in fuselage possible but forward of the ver/cal fin •  Must be oriented so iner/a switch is ac/vated by a 5G force along the longitudinal axis ELT •  Usually portable with a portable antenna so the pilot can take it with him •  Non-­‐rechargeable baJeries must be replaced when they reach 50% of their usable life •  Rechargeable baJeries must be charged when they reach 50% of their charge •  Recharge or replace baJery aAer 1 hour of use •  ELT baJeries have a replacement date Date must be marked on the outside of the transmiJer case !  Date must be recorded in maintenance records !
ELT Tes/ng •  121.5/243 MHz Test during first 5 minutes aAer hour !  Use standard com radio (VHF) set to 121.5 and use manual ac/va/on switch !  Keep short – three audio sweeps !  If removed from aircraA, use dummy load antenna !
•  406 MHz !
Follow manufacturers tes/ng instruc/ons LORAN •  LOng Range Aid to Naviga/on •  Originally used for marine naviga/on •  Determines aircraA loca/on by means of pulsed signals transmiJed from ground sta/ons •  Replaced by GPS AC43-­‐13-­‐2B Highlights •  When installing new electronics, consider the impact when radio frequency such as electromagne/c interference (EMI), high intensity radiated fields (HIRF), or lightning may nega/vely affect exis/ng systems (e.g., accuracy of the magne/c compass). •  Ensure that the capacity of the aircraA’s charging system is not exceeded •  Care should be taken to ensure that cables or wires will not interfere with the aircraA’s flight, engine, or propeller controls. AC43-­‐13-­‐2B Highlights •  Ensure there is: !
There is appropriate air circula/on to ensure proper cooling and dissipa/on of any heat generated or present. •  Fans may need to be added !
There are appropriate clearances to prevent mechanical damage to other parts of the aircraA or from other parts of the aircraA. •  Structural loads must be adequately transferred to primary airframe members. AC43-­‐13-­‐2B Highlights •  Installa/on of an electrical system or component into an aircraA requires considera/on of the electrical load, the appropriate power distribu/on circuit, and available power capacity. •  Install wire in a manner suitably protected from fuel, oil, water, other detrimental substances, oxygen systems, and abrasion damages. •  Incorporate a “trip free” re-­‐seJable type circuit breaker or a fuse in the power supply from the bus. Mount in a manner accessible to a crewmember during flight for circuit breaker reserng or fuse replacement and label. AC43-­‐13-­‐2B Highlights •  Physically separate radio electric wire bundles from lines or equipment containing oil, fuel, hydraulic fluid, alcohol, or oxygen. •  Route and support electrical wire bundles and mechanical cables in a manner that will allow normal mo/on of equipment without strain or damage to the wire bundles or mechanical cables. AC43-­‐13-­‐2B Highlights •  Electrically bond radio equipment to the aircraA in order to provide a low impedance ground and to minimize radio interference from sta/c electrical charges. Keep bonding jumpers as short as possible. !  Prepare bonded surfaces for best contact (resistance of connec/ons should not exceed 0.003 ohm). !  Avoid use of solder to aJach bonding jumpers. Clamps and screws are preferred. !
AC43-­‐13-­‐2B Highlights •  Electrically bond radio equipment For bonding aluminum alloy, use aluminum alloy or /nned or cadmium-­‐plated copper jumpers. Use brass or bronze jumpers on steel parts. !  When contact between dissimilar metals cannot be avoided, put a protec/ve coa/ng over the finished connec/on to minimize corrosion. !
AC43-­‐13-­‐2B Highlights •  Follow antenna manufacturer’s instruc/ons and recommenda/ons when they are available and appropriate, and not contrary to the instruc/ons of the aircraA manufacturer. •  Extension of the landing gear or flaps may impact belly-­‐mounted antenna performance. !
May block recep/on •  The antenna’s structural load, plus any required allowances, may not exceed the design capacity of the structure intended to support it. AC43-­‐13-­‐2B Highlights •  Since antenna systems typically require a ground plane (this may be a conduc/ve surface that the antenna mounts to) any separa/on of an antenna from its ground plane may impact performance. Contact the manufacturer for recommenda/ons if a gasket or moun/ng saddle is needed. !
Gaskets are commonly used to to prevent the entry of moisture AC43-­‐13-­‐2B Highlights •  Consider the factors of fluJer, vibra/on characteris/cs, and drag load. The approximate drag load an antenna develops may be determined by the formula: !
D=0.000327 AV2 •  (The formula includes a 90 percent reduc/on factor for the streamline shape of the antenna.) D is the drag load on the antenna in lbs. A is the frontal area of the antenna in sq. A. V is the VNE of the aircraA in mph. AC43-­‐13-­‐2B Highlights •  D=0.000327 AV2 !
Example: Antenna manufacturer specifica/on frontal area = 0.135 sq. A. and VNE of aircraA is 250 mph. •  D=0.000327 X 0.135 X (250)2 D=0.000327 X 0.135 X 62,500 D= 2.75 lbs •  Antennas should be located where they will not interfere with the opera/on of the aircraA or other aircraA systems. •  Pain/ng an antenna or applying protec/ve coa/ngs or devices that are not approved are not allowed under this AC. AC43-­‐13-­‐2B Highlights •  Antennas should be located in such a manner that they are not suscep/ble to damage from misuse, such as near a door where they might be mistaken for or used as a handhold. •  Most antennas require a ground plane size of approximately 24" by 24". While the rule of thumb is to provide a minimum of 1/4 wavelength of the opera/on frequency, larger is beJer and ground plane symmetry is cri/cal. !
See table 3.1 Antennas Installa/on •  Changes/Upgrades Follow the manufacturer's recommenda/ons !  Requires an STC and 337 !  Verify power load on electrical system !  Verify mechanical support !
•  Shock mount for high-­‐frequency, low-­‐amplitude vibra/on •  Insure chassis are grounded to prevent sta/c charges •  Insure clearance from moving parts Check weight and balance !  Update POH material !  Update maintenance informa/on !
Sta/c Protec/on Nullfield sta/c dischargers are installed on the trailing edges of control surfaces to carry sta/c electrical charges into the atmosphere, before they build up a high enough voltage to interfere with the electronic equipment. Sta/c Protec/on •  Reduces sta/c charge by bleeding off charge in a slow, low current, controlled manner •  Don’t paint, cover, move or disconnect Antenna Loca/on •  VHF (communica/ons) and VOR are commonly combined into one antenna VHF and VOR are in the same frequency range !  Looks like a “ V” on the tail or top of fuselage !
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Glide Slope built into VOR antenna Marker Beacon – boJom of fuselage ADF – boJom of fuselage DME – boJom and centerline of fuselage Antenna loop must be calibrated aAer installa/on !  Insure wings don’t block signal during a turn !
Antenna Loca/on •  Transponder – boJom and centerline of fuselage Can look just like a DME antenna !  Keep far away from DME antenna !
•  ELT – back end and top of fuselage. Ahead of empennage •  GPS – top of fuselage Autopilot •  Autopilot – a system that will automa/cally fly an aircraA Pilot enters desired ac/on !  Autopilot uses sensing element to determine the aircraAs status !  The autopilots computer determines what ac/on that needs to be taken !  Autopilot manipulates control surfaces (and engine) to obtain desired ac/on !
•  FAA say the primary func/on is to relieve the pilot of the control of the aircraA during long periods of flight Autopilot Func/ons •  Wing leveler – simplest •  Flight Director Used on large aircraA to control almost every aspect of a flight !  Modern systems are capable of takeoffs and landings !  Controlled by a Flight Management Computer !
•  Modern fighters are so unstable that the autopilot is in control, the pilot is just an input •  Yaw damper – counteracts Dutch rolls (tail wagging) •  Disaster recovery Autopilot Sensing Systems •  Gyros – measures rela/ve movement •  Air pressure Al/tude (Radar al/meters also used) !  Airspeed !
•  Iner/al guidance systems Detects aircraA movement !  Uses gyros and accelerometers !
•  Radio naviga/on VOR !  Glideslope !  GPS !
Autopilot Servos •  Convert electrical signals to mechanical ac/on to manipulates control surfaces !
An electric motor •  May be connected directly to the aircraA control surfaces •  May be connected to the control cables •  May be connected to the hydraulic valves to gain mechanical advantage •  Three axes needed to completely control aircraA •  Older systems use a follow-­‐up signal for feedback !
Nullifies input signal FAA Ques/ons •  Which of the following provides manual maneuverability of the aircraA while the autopilot is engaged? a. Servo-­‐amplifier. !  b. Direc/onal gyro indicator. !  c. Flight controller. !
FAA Ques/ons •  Which of the following provides manual maneuverability of the aircraA while the autopilot is engaged? !
c. Flight controller. FAA Ques/ons •  What will occur if an aircraA artude is changed by its autopilot system in order to correct for an error and the involved control surfaces are returned to streamline by the /me the aircraA has reached its correct posi/on? a. Overshoot and oscilla/on. !  b. Undershoot and oscilla/on. !  c. Normal opera/on. !
FAA Ques/ons •  What will occur if an aircraA artude is changed by its autopilot system in order to correct for an error and the involved control surfaces are returned to streamline by the /me the aircraA has reached its correct posi/on? !
c. Normal opera/on. FAA Ques/ons •  When opera/onally checking an autopilot system on the ground, aAer the aircraA's main power has been switched on, the autopilot should be engaged a. only aAer the gyros come up to speed and the amplifier warms up. !  b. whenever the operator desires. !  c. for only a few minutes at a /me. !
FAA Ques/ons •  When opera/onally checking an autopilot system on the ground, aAer the aircraA's main power has been switched on, the autopilot should be engaged !
a. only aAer the gyros come up to speed and the amplifier warms up. FAA Ques/ons •  When must the radio sta/on license be displayed in an aircraA equipped with a two-­‐way radio? a. When the aircraA is operated outside the U.S. !  b. When the aircraA is returned to service. !  c. When the aircraA is cer/fied for IFR flight. !
FAA Ques/ons •  When must the radio sta/on license be displayed in an aircraA equipped with a two-­‐way radio? !
a. When the aircraA is operated outside the U.S. FAA Ques/ons •  When would a U.S. resident NOT be required to hold a Federal Communica/ons Commission (FCC) Restricted Radio Telephone Operator Permit to operate two-­‐way aircraA VHF radio equipment? a. When flying to or communica/ng with des/na/ons outside the United States. !  b. When flying or communica/ng within the United States. !  c. When the radio equipment is operated in aircraA cer/fied for VFR flight only. !
FAA Ques/ons •  When would a U.S. resident NOT be required to hold a Federal Communica/ons Commission (FCC) Restricted Radio Telephone Operator Permit to operate two-­‐way aircraA VHF radio equipment? !
b. When flying or communica/ng within the United States.