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Aircraft Communication and Autopilot Systems

• Aircraft Avionics deals with Aircraft Communication and Autopilot Systems (AVIONICS-AS)
• This document continues the conversation surrounding Aircraft Communication Systems

Radio Theory

• Transmission and detection of communication signals are emphasized
• Communication signals consist of electromagnetic waves
• Electromagnetic waves travel through the air in a straight line
• Electromagnetic waves travel by reflection from the ionosphere
• Electromagnetic waves travel by communication satellite

Wave Basics

• A wave is a progressive disturbance in a medium
• Waves move outward and possess energy
• Energy is lost due to friction
• Waves have peaks called crests and valleys called troughs
• The distance between crests is called the wavelength

Electromagnetic Waves

• Electromagnetic waves form when an electric field contacts a magnetic field
• The electric and magnetic fields of an electromagnetic wave are perpendicular at right angles to each other

Radio Waves

• Radio waves are a type of electromagnetic wave
• Located on the electromagnetic spectrum are lower frequencies than microwaves
• Radio waves are used in standard broadcast radio, television, shortwave radio, navigation, air-traffic control, cellular telephony, and remote-controlled toys
• The SI unit for wave frequency is the hertz (Hz)
• One hertz equals one wave passing a fixed point in one second
• A higher-frequency wave has more energy than a lower-frequency wave with the same amplitude

Radio Wave Frequencies

• Low frequency features include:
• Long Wavelength
• Low Energy
• Poor Quality
• High frequency features include:
• Short Wavelength
• High Energy
• Good Quality

Factors Affecting Radio Waves

• Diffraction occurs in low-frequency radio waves and is the bending of the wave
• Reflection occurs in high-frequency radio waves and is the bouncing back of the wave
• Refraction occurs in high and low-frequency radio waves and is the changing direction of the wave by a disturbance
• Attenuation is a reduction of signal strength during transmission from energy loss of a radio wave; friction may cause it

Radio Wave Propagation

• Radio waves are transmitted omnidirectionally, directionally, or using the pulse & echo method
• Radio waves move from the antenna along 3 paths depending on its frequency: surface waves, sky waves, and space waves

Omni Directional Radio Waves

• Omni directional radio waves are propagated in all directions

Directional Radio Waves

• Directional radio waves are propagated in one direction

Pulse & Echo Radio Waves

• Pulse & echo radio waves operate by bouncing back

Types of Radio Waves

Ground Waves / Surface Waves

• Ground waves follow the curvature of the Earth and these waves are restricted by gravity
• VLF, LF, and MF waves are types of ground waves

Sky Waves

• Sky waves are stronger than ground waves and can overcome gravity but cannot penetrate the ionosphere
• HF waves are a type of sky wave

Space Waves

• Space waves can overcome gravity and penetrate the ionosphere, but their limitation is line of sight
• VHF, UHF, SHF, and EHF are types of space waves

Common Frequency Bands and Applications

• VERY LOW (VLF) band has a frequency range of less than 30 KHz and has LORAN in COMMON APPLICATION
• LOW (LF) band has a frequency range of 30-300 KHz band has NDB (200-415, 510-535 KHz) in COMMON APPLICATION
• MEDIUM (MF) band range is 300-3000 KHz with NDB, Radio Station, (550-1750 KHz) in COMMON APPLICATION
• HIGH (HF) frequency band range is 3-30 MHz with SELCAL in COMMON APPLICATION
• VERY HIGH (VHF) frequency range is 30-300 MHz with VH NAV/COMM, VOR TACAN, DME, LOC/GS in COMMON APPLICATION
• ULTRA HIGH (UHF) and SUPER HIGH (SHF) frequency range is 300-3000 MHz and they are used for Microwave in COMMON APPLICATION
• EXTREMELY HIGH (EHF) frequency range is 30-300 GHz band range

Radiotelephony Definition

• Radiotelephony involves pilots, engineers, and air traffic controllers using standardized words/phrases approved by ICAO for routine aircraft communications

Radiotelephony Techniques According to the ICAO Doc 9432 Manual

• Listen on the frequency before transmitting to avoid interference with other stations
• Use good microphone operating techniques
• Use a normal conversational tone and speak clearly/distinctly
• Maintain a rate of speech not exceeding 100 words/minute; slow down if elements of the message will be written down by the recipient
• Keep the speaking volume constant
• Pause slightly before and after numbers
• Avoid hesitation sounds such as "er"
• Depress the transmit switch fully before speaking, and don't release it until the message is completed
• Ensure that the microphone button gets released after a transmission
• Place the microphone in an appropriate place so it will not inadvertently be switched on

HF and VHF Communication Systems

• VHF and HF communication systems use transceivers
• A transceiver is a self contained transmitter and receiver
• The transmitter and receiver both operate at the same frequency, and the microphone button determines when there is an output from the transmitter
• In the absence of transmission the receiver is sensitive to incoming signals
• The combination of transmitters and receivers saves space and weight

VHF Communication

• Very High Frequency describes the 30MHz to 300MHz portion of the radio spectrum
• This frequency range provides short-range LOS (line of sight) communications
• The range for communications depends on equipment, height, and terrain ( ranges from 2 to 20 miles typically)

HF Communication

• The frequency range is 3-30 MHz
• This is used for long range communications due to its long transmission range, and transmissions are reflected from the ionosphere
• HF transmitters have higher power outputs than VHF transmitters
• A Tuner matches the impedance of the transceiver to the antenna
• The installation of the HF communication system is the same as that of the VHF communication system
• The HF communication system can transmit information over long distances because the HF transmitter's output power is higher than that of the VHF transmitter

Service Interphone System

• The service interphone system provides ground crew personnel and all aircraft crewmembers with facilities that enable two-way voice communications during aircraft servicing or during normal flight operations
• Handset jacks are located throughout the aircraft, internally and externally for use by ground personnel to facilitate aircraft servicing and maintenance
• The service interphone switch on pilots' overhead panel P5 disconnects these jacks from the system when not in use

Passenger Address System

• The passenger address (PA) system provides a means of communicating with passengers and entertaining them with music played over the passenger compartment speakers
• It also provides chime signals for the Passenger Call Systems, Flight Crew Call System, and Passenger Signs to attract the attention of flight attendants/passengers
• Announcements may be made through hand microphones or audio selector panels in the flight interphone system
• The passenger address system consists of a PA amplifier, loudspeakers, microphones, a tape reproducer, and interconnecting wiring

SELCAL Systems

• SELCAL is a signaling method that alerts an individual aircraft when a ground station wants to communicate with it, and two identical systems are installed in the aircraft
• A 4-tone alert signal from a ground station is sent to an aircraft VHF or HF system that is detected by the SELCAL system
• The system alerts the crewmembers with a light and chime when a message is received on one of the communication systems
• The components of the SELCAL systems include a decoder, chime, and SELCAL control panel
• The chime is enclosed within the aural warning unit on the forward right side of the control stand
• The SELCAL control panel is installed on the pilots' aft overhead panel

Communication Definition

• Communication is transmitting information from one party to another by using radio, METAR, ATIS, etc

Basic Communication Equipment

• VHF Radio
• Transponder
• ELT

VHF Radio

• VHF communication systems maintain contact between ground and aircraft and use "Line Of Site" transmission

Transponders

• A transponder is a device that receives a radio signal and responds
• Mode A Identification is a squawk code
• Mode C Identification includes altitude (Pressure Altitude)
• Mode S Identification includes altitude, and data exchange

Transponder Details

• "Squawk" assigns a transponder code
• The transponder is read Right to left from code 0-7

Basic Squawk Codes

• 1200 - VFR
• 7500 – Unlawful Interference
• 7600 – Radio Failure/Lost Communications (NORDO)
• 7700 – Emergency (SOS, MAYDAY)

Transponder Buttons

• OFF Button
• ON Button
• STBY Button
• ALT Button
• IDENT Button

Emergency Locator Transmitter (ELT)

• Broadcasts distinctive signals on designated frequencies and may activate automatically by impact or may be manually activated
• ELTs are Self-contained and self powered
• Civil distress frequency- 121.5 MHz
• New ELTS frequency- 406 MHz
• Military distress frequency -243 MHz
• All operate automatically when the unit recognizes impact of 5G
• Their battery should power for at least 48 hours
• Batteries should be recharged or changed at 50 percent of the battery’s useful life

Categories of Messages by Priority

• Distress calls, distress messages, and distress traffic, signal: MAYDAY
• Urgency messages, include messages preceded by the signal for medical transports: PAN PAN or PAN PAN MEDICAL
• Direction finding messages includes: Heading, bearing, radial, track or course
• Flight Safety Messages includes - Movement and control messages, Messages from Aircraft Operation of aircrafts and Meteorological advice on the flight
• Flight Regularity Messages is messages from management to operation or maintenance of any aircraft,servicing or operational operation

Standard Words and Phrases

• ACKNOWLEDGE: "Let me know that you have received and understood this message."
• AFFIRM: "Yes."
• APPROVED: "Permission for proposed action granted."
• BREAK: "I hereby indicate the separation between two or more messages."
• CANCEL: "Annul the previously transmitted clearance."
• CHECK: "Examine a system or procedure."
• CLEARED: "Authorized to proceed under specified conditions."
• CONFIRM: "I request verification of: (clearance, instruction, action, information)."
• CONTACT: "Establish communications with..."
• CORRECT: "True" or "Accurate".
• CORRECTION: "An error has been made in this transmission. The correct version is..."
• DISREGARD: "Ignore."
• GO AHEAD: "Proceed with your message."
• HOW DO YOU READ?: "What is the readability of my transmission?"
• I SAY AGAIN: "I repeat for clarity or emphasis."
• MAINTAIN: Continue in accordance with the condition(s) specified
• MONITOR: "Listen out on (frequency)."
• NEGATIVE: "No" or "Permission not granted" or "That is not correct" or "not capable".
• READ BACK; "Repeat all, or the specified part, of this message"
• RECLEARED: "A change has been made to your last clearance and this new clearance supersedes your previous clearance."
• REPORT: "Pass me the following information..."
• REQUEST: "I would like to know..." or "I wish to obtain..."
• SAY AGAIN: "Repeat all, or the following part, of your last transmission."
• SPEAK SLOWER: "Reduce your rate of speech."
• STANDBY: "Wait and I will call you."
• UNABLE: "I cannot comply with your request, instruction, or clearance."
• WORDS TWICE: "Please send every word or group of words twice."

Call Signs for Aircraft

• Registration Markings such as RP-C 1049
• Telephony designator of the aircraft operating agency such as Qatari
• Telephony designator of the aircraft operating agency, followed by the flight identification such as Cebu 149

Call Signs for Aeronautical Stations consist of

• Name + Call Sign Suffix such as Manila Control
• Call Sign Suffix Examples:
• AREA CONTROL CENTRE uses CONTROL
• APPROACH CONTROL: APPROACH
• APP CTRL RADAR ARRIVAL: ARRIVAL
• APP CTRL RADAR DEPARTURE :DEPARTURE
• AERODROME CONTROL: TOWER
• SURFACE MOVEMENT CONTROL: GROUND
• CLEARANCE DELIVERY: DELIVERY
• APRON CONTROL: APRON
• COMPANY DISPATCH: DISPATCH
• FLIGHT SERVICE STATION : RADIO

Weather Reports

• ATIS(Automatic Terminal Information Service) is used to inform any terminal automatic operations
• METAR(Meteorological Aerodrome Report) is Meteorological Aerodrome Report as an airport
• TAF (Terminal Aerodrome Forecast)is used when giving A Terminal Aerodrome Forecast

VFR Procedures are:

• Start-up
• Clearances
• Departure Procedures
• Enroute Procedures
• Arrival and Approach Procedures
• NORDO Procedures

Standard Call

• The parts of the standard call [Addressee], [callsign], [type], [location], [Alt]
• [Identification Ready for departure to [destination], [remarks] Intention
• Clark Tower, uses RP-C Cessna 152, VFR, is currently at holding point 02 Omni, and Is Ready for departure to Charlie Areas, Airworks

Read Back

• At specific instructions are provided by the tower a pilot should read back the entire instruction with his ident at the end
• Tower: RP-C taxi via Alpha Left on Bravo and hold short taxiway Charlie
• Pilot: Alpha Left Bravo, hold short Charlie, RP-C
• Tower: Averts it the Read Back, Correct

Start up and Taxi is Controlled

• In Initial Call
  • Tower: Go Ahead
  • Pilot: RP-C Charlie Ramp, request engine start-up, and get a request approved the taxi instruction would then be provided to the tower

Uncontrolled

• There is no need to Call in

Clearance for Take-off should give specific signals for each aircraft or tower

• A pilots should Say Where it is the plane of flight the tower they are taking Off to or report Airbourne to

Departure proceedures

• Upon AirBourne to decide Type of departure,advise ARC and comply with the instructuon via the REad Bacak

VFR Enroute Procedures

• Controlled-Comply with ARCAPP instructions via Read Bac
• Uncontrolled —- The tower must report over Mexico / listen,think and talk

Air Navigation

• Aircraft navigation is the science and technology of determining the position of an aircraft to the surface of the earth and maintain an accurate path

Visual Flight Rules -VFR-

• Rules that govern the operation of an aircraft in Visual Meteorological Conditions -VMC-
• Flight is always possible but sometimes has limitations because of traffic patterns

pilotage Is:

• The use of fixed Visual references on the ground to guide ones self to the aircraft to help to the destination on the route by map/aeronatical chart

An aeronautical chart is:

• A roadmap for a pilot flying -under - VFR-
• Helps to track you and the information that is open to Enhance safety

Deducted Reckoning

• DR Is a method of navigation that can estimate one's current path, groundspeed and based position

Heading versus Track

• Heading — Direction airplane is pointed
• Track — Direction Airplane is moving
• Drift angle = Track —- heading +/- Nose direction

Radio Navigation

• Radio Navigation is when navigating or piloting of the aircraft using onky the instruments and navigational systems Like VHR /Onni or ADF

Instrument Flight Rules is set to dictate

• How air are and will opperated because it is impossible for a aircraft visual references are under any flight rules

Oldest navigational system ADF Automatic Direction Finding

• Aids electronic identification at navigation to determine the air craft from a radio spectrum

Non directional Beacon

• 190/415 5203.5 km

HDF/NDB borne Eauipment Antenna

• Directional antenna
• sensical antenna
• ADF receiver
• ADF indicators

Definition of Terms

• Magnetic Heading (MH)- Direction aircraft’s nose is pointed.
• Relative Bearing (RB) -Degrees from the nose of the aircraft to the transmitter clockwise.
• Magnetic Bearing to/from (MBTO / MBFROM)- Direction to be flown to/from the station.

how ti find the line of precision

• MH + RB = MBTO MBTO +/- 180 = MBFROM = LOP

Types of ADF indicator

• Fixed Card ADF
• Always shows 0 0°at the top.
• The needle always points toRelative Bearing (RB).
• Movable Card ADF
• Manually adjusted to show magnetic heading at top. The needle always points toMagnetic Bearing to the station
• (MBTO)

VHF and Omni direction

Radio Range Navigation System The most widely used range 4 /- or accuraccy,Automatic can compinsatr for the drift

• VHR or transmit the station is code indentified to the the airborne equipment to determine distance in the Morse 108.117,85 and MHs
• The station also identifies there local voice Operation transmission at the magnetic north

VOR station

is close around the lines and can pick uo the transmitter and is used around 280miles Each station broadcasts an HFR station The navagation is from one station to another of north - 3 leter string to the Morse Code

VOR

Station Work are also omni direction Is also directional of the station

terminal vor

• A low-powered VOR (very high frequency omnidirectional radio- range) located at or near an airport at which a particular flight terminates and which has been specified as a NAVAID (navigational aid) in the final approach clearance
• Terminal VOR (TVOR) has a range of 25NM from 1,000 feet AGL to 12,000 feet AGL.

LOW VOR

Low-altitude VORs are meant to be used from 1,000 feet AGM throught 18000 feet AGM at distances of up to 40 Nm from the station

High Altitude VOR

High Altitude VOR (HVOR) is a little trickier and has several different service volumes based on altitude

VORMAP

• Depictions are VHR in Omni

• Range -VROTAC, VRO-DME - charts is based on Different Simpils

VOR Airborne that are Eaiioed

• Vor Equiped with antenna and VHF NAV Indication
• Vor indicate a station

Parts of the VOR

1. Omni Bearing Selector -To be tunned in the direction on the the campis card
2. To and from indicator- to see if the course on going from The station or on the side 158)1 (0 1/4 Is also deviated to move the aircraft more and there is a Outer dot is 10 deg/2 des per dor

To use the VRO away Fromn a statain;

The OBS to be put in place of FR or

1. To use the OBS for to see what direction is is showing at te

• From indicator is a VHR that is showing A way

Steps are how to use the VOR

1). To spin the OBSS untik TO showing To centre what is at the radial of reciprocal is to course the index

Some things to understand before going to the VOR

1. Tine in the station
2. Identiffy the Morse code in the transmission
3. Test the VOR by testing all functions are correct

VOR 4.0

• Acuraccy,Sensativity Ambuigity

VOR Limitations

• Terrain are in place, the the radio signal cant push
• Confussion with the code, the off position and the signal and the symbol comes up
• • Zone Ambiguity at the centre TOs are are going Reverse of sensor when on the the pilot Distance measuring equipment Distance Measures the A navigation in which The aircarft Is based and measures the position Aircraft are being sent to fixed Delay to the DME Ground station is been computed distance based the beacon using DMS the aircarfts based on its speed

VR and DM

• VOR can measure any readal but to find the location need two see the the radials
• Distance is measured, The frequency high (1- and is to for both parts plane on the ground Aircraft sends is then and and is in active mode

Precision Approach

1. Manker Beacons

• Vertically radio sign indicagins the the runway and can help determine the position
• Are different types of beacons Outer -Middle - and Inner

Outer marker

• Marks. the final approach fix and four of the seven Nauluc miles from the It's
• Usually one miles where the guide scope
• The wave signal it send is an ellipse

Middle -Beacon

Beacon Works where normally beaconed to be of nautc mile

The alerts are often done if thee is an Is an and alerts the pitol that

The inner beacon

• Is the beacon is is located at the start or Threshold of landing
• Usually shows 200 feet
• Flashes white light audio for more details around

Approach lights system

The system shows mean a 90 1500 ft Non precciosm

• The systems also include flash of 1s where the light

VASI

• A system of light used to provide visual descendent
• A system from 325 miles used to see the the route clearly
• A red and white set up of lights show the path it set on

Precision Approach Path Indicator-PAPI-

Are light that provide visual approched and are are set in different locations 28 NM away from the runway the path shows and the

ILS Indicator

• Localizer glideslope marked Becons approached and approach

Limitations of ILS

• Localizer systems that a sensitive and obstruct
• Gide Slopes are sensitive of to the terrain sloping causing uneven needle defectoons
• Its Critical areas are is always is established location will will have to take the delays

Categories of ILS Appraoch

Microwave landing system

• (MLS) Landing systems that provide and help assist with weather related issues

intertial Navigation system the :INS:

• Self contact system of the aircraft
• Helps show the and provide details