PPL Radiotelephony Manual Antonios Papadakis
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Chapter 1: Radio Theory PUSH TO TALK 1.1 Producing a radio wave 1 1.2 Frequency and Wavelength.. 1 1.3 The frequency spectrum 2-3 1.4 Adding information..3-6 1.5 Cockpit equipment 6-7 1.6 Ground direction finding.8-9 1.7 Distress frequencies...9 Chapter 2: Aeronautical Mobile Service Introduction.12-13 2.1 Category of messages.....14 2.2 Distress calls...14-18 2.3 Urgency messages..19 2.4 Direction finding.. 20-21 2.5 Flight safety messages..21 2.6 Meteorological messages.22 2.7 Flight regularity messages..22 2.8 Aircraft communications failure 23-24 Chapter 3: Radio Techniques and Phraseology Introduction. 27 3.1 Transmitting...27-28 3.2 Transmission of time..28 3.3 Transmission of letters..29 3.4 Transmission of numbers. 30 3.5 Transmission of frequencies.....31
3.6 Standard words and phrases..32-33 3.7 Call signs. 34-36 3.8 Continuation of communications....36-37 3.9 Transfer of communications.....38 3.10 Clearance issue and read back requirements..38-40 3.11 Test Transmissions 40-41 3.12 Routine position reports..42-43 3.13 Automatic terminal information service (ATIS).. 43-44 Chapter 4: Aerodrome Control of Aircraft 4.1 Pre-Start procedures.47-48 4.2 Taxi instructions..48-49 4.3 Take-off procedures.49-53 4.4 In the cirquit..54-56 4.5 Final approach and landing 57-58 4.6 Go around..58-59 4.7 After landing.60
Chapter 1 Radio Theory Page 0
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1.1 Producing a radio wave To produce a radio wave we need an oscillating electrical current and an aerial. The electrons moving backwards and forwards in the aerial produce a changing electrical field which moves away from them at the speed of light. We call this electrical field a wave. 1.2 Frequency and Wavelength The number of cycles a wave performs in 1 second is called frequency ( f ) and is measured in Hertz (Hz). The distance a wave travels during one cycle is called wavelength ( l ) and is measured in meters (m). The relationship between frequency and wavelength is expressed by the formula: Where c = 3 x 10⁸ m/s the speed of light. c = l x f High frequencies have low wavelengths and vice versa. Page 1
1.3 The frequency spectrum Aviation communications use the VHF band from 118MHz to 137MHz. Frequency spacing can be 25KHz or in most recent transmitters 8.33KHz. Factors affecting range include: Transmitter power Height of transmitter and receiver Obstructions Page 2
Maximum theoretical range of a VHF or UHF signal can be calculated by the formula: Max Theoretical Range = 1.23 H1 + 1.23 H2 Where H1 the height of the transmitter and H2 the height of the receiver in feet measured AMSL and the range output expressed in nautical miles. 1.4 Adding information The frequency of the radio wave on its own is not audible. Even if it was, it would only be heard as a monotone. Any information to be transmitted must be laid on top of this wave, which now acts as a carrier wave, before transmission and decoded by the receiver. This is known as modulation and de-modulation. Amplitude Modulation The simplest form of modulation is to vary the strength or the amplitude of the carrier wave to transmit information. This is called amplitude modulation (AM). AM is cheap and simple to do. It is though venerable to static noise and interference. Page 3
Frequency Modulation As an alternative to varying the amplitude the frequency may be varied. This is known as frequency modulation (FM). FM is more complex but reduces static and interference. Page 4
Pulse modulation Pulse modulation sends digital data or Morse. Page 5
1.5 Cockpit equipment The panel used to select witch transceiver we use and to control intercom, is called audio box. Page 6
The upper line of buttons allows us to select the source we want to hear (e.g. COM1 or 2, NAV, ADF). The COM1MIC etc buttons allow us to select the comm. we want to talk to. Usually by pressing a COM_MIC button the upper selection is done automatically. There are two knobs to control volume and sensitivity. The left knob is also the ON/OFF knob. We select the frequency we want to use from the transceiver box. Select frequency. Swap standby and active frequency. Volume and ON/OFF control (by pushing inwards you cancel Squelch). Page 7
1.6 Ground Direction Finding Some VHF radio stations are equipped with automatic direction finding (VHF DF). Bearing information can be provided on request expressed as either true or magnetic direction either to or from the station. A Q code is used to avoid confusion. QTE : true bearing from the station QDR : Magnetic bearing from the station QDM : Magnetic bearing to the station Page 8
Bearings are classified by their quality. There are four classes according to the accuracy of the station. Class A : ±2 Class B : ±5 (the most common) Class C : ±10 Class D : more than 10 1.7 Distress Frequencies A number of specific radio frequencies are used as distress frequencies. 121.500MHz (VHF) 243.0MHz (UHF) 500KHz (MF) 2182KHz (MF) Aeronautical Emergency Frequency Military Emergency Frequency International Distress Frequency International Distress Frequency Page 9
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Chapter 2 Aeronautical Mobile Service Page 11
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The Aeronautical Mobile Service is the term for air to air or ground to air communications. The rules for using the aeronautical mobile network are laid out in ICAO Annex 10 Volume 2. Some general guide lines are: In all communications, the highest standard of discipline shall be observed at all times. In all situations for which standard radiotelephony phraseology is specified, it shall be used. The transmission of messages on aeronautical mobile frequencies, when the aeronautical fixed services are able to serve the intended purpose, shall be avoided. The consequences of human performance can affect understanding of messages and should be taken into consideration. Except as otherwise provided, the responsibility of establishing communication shall rest with the station having traffic to transmit. Page 12 After a call has been made to the aeronautical station, a period of at least 10 seconds should elapse before a second call is made. This should eliminate unnecessary transmissions while the aeronautical station is getting ready to reply to the initial call.
When an aeronautical station is called simultaneously by several aircraft stations, the aeronautical station shall decide the order in which aircraft shall communicate. In communications between aircraft stations, the duration of communication shall be controlled by the aircraft that is receiving, subject to the intervention of an aeronautical station. If such communications take place on an ATS frequency, prior permission of the aeronautical station shall be obtained. Such request or permission is not required for brief exchanges. Intentionally blank Page 13
2.1 Category of Messages The categories of messages and the order they shall be dealt with are: 2.2 Distress Calls A state of distress exists when being threatened by serious or imminent danger and requiring immediate assistance. Page 14
Actions to be taken by an aircraft in distress The distress message sent by an aircraft in distress should be sent on the last active frequency and should be preceded by the distress signal MAYDAY spoken three times. The message should consist of as many as possible of: The name of the station addressed. The identification of the aircraft. The nature of the distress condition. The intention of the person in command. The present position, altitude and heading. Actions to be taken in reply The first station acknowledging the message should: Immediately acknowledge the distress message. Take control of the communications or specifically and clearly transfer that responsibility, advising the aircraft if a transfer is made. Take immediate action to ensure that all necessary information is made available, as soon as possible. To the ATS and the aircraft operating agency. Warn other stations as appropriate, in order to prevent the transfer of traffic to the frequency of distress communications. Page 15
Imposition of silence The station in distress or the station in control of distress traffic, shall be permitted to impose silence, either on all stations of the mobile service in the area or any station that interferes with the distress traffic. It shall address these instructions to all stations, or to one station only using the message STOP TRANSMITTING and the distress signal MAYDAY. Page 16
Actions by all other stations The distress communications have absolute priority over all other communications, and a station aware of it shall not transmit on the frequency concerned unless: The distress is cancelled or the distress traffic is terminated All distress traffic has been transferred to other frequencies The station controlling communication gives permission It is obliged to render assistance. Page 17
Termination of distress communication and of silence When an aircraft is no longer in a distress condition it can cancel the distress. The distress communication and silence shall be terminated by transmitting a message using the words DISTRESS TRAFFIC ENDED. Only the station controlling the communications can originate this message. Page 18
2.3 Urgency messages A state of urgency is a condition concerning the safety of an aircraft or other vehicle, or of some person on board or within sight, but which does not require immediate assistance. Action by an aircraft reporting urgency conditions Urgency messages are preceded by the phrase PAN PAN preferably spoken three times. The message should consist: The name of the station addressed The identification of the aircraft The position and altitude of the aircraft The nature of the urgency condition The intention of the person in command Page 19
2.4 Direction Finding A bearing may be requested using the Q code or in plain English speaking TRUE BEARING twice at the beginning of the message. By convention the Q codes are used for magnetic bearings to and from the station and plain English is used to request a true bearing from the station.the aeronautical stations that offer VDF services are listed in the AIP AD.VDF bearings will be given when conditions are satisfactory and radio bearing fall within calibrated limits of the station Page 20
2.5 Flight Safety Messages Flight safety messages are the following: Movement and control messages. Messages originated by an aircraft operating agency or by an aircraft of immediate concern to an aircraft in flight. Meteorological advice of immediate concern to an aircraft in flight or about to depart. Other messages concerning aircraft in flight or about to depart. Most communications between ATC and aircraft falls into this category. Page 21
2.6 Meteorological Messages Are messages to or from aircraft containing meteorological information other than that listed as a flight safety message. 2.7 Flight Regularity Messages The class of messages labeled as flight regularity messages contains the following: Messages concerning the operation or maintenance of facilities essential for the safety or regularity of aircraft operation. Messages concerning the servicing of aircraft. Instructions to aircraft operating agency representatives concerning changes in requirements for passengers and crew, caused by unavoidable deviations from normal operating schedules. Messages concerning non-routine landings to be made by aircraft. Messages concerning aircraft parts and materials urgently required. Messages concerning changes in aircraft operating schedules. Page 22
2.8 Aircraft Communications Failure When an aircraft station fails to establish contact with the aeronautical station on the designated frequency, it shall attempt to establish contact on another frequency appropriate to the route. If this attempt fails the aircraft shall attempt to establish communication with another aircraft or other aeronautical stations appropriate to the route. In addition, an aircraft operating within a network shall monitor the appropriate VHF frequency for calls from nearby aircraft. If the attempts specified above fail the aircraft station shall transmit its message twice on the designated frequency, preceded by the phrase TRANSMITING BLIND. Blind transmissions should be transmitted twice on both primary and secondary frequencies. Before changing frequency the aircraft should announce the frequency to which it is changing. Receiver Failure When an aircraft is unable to communicate due to receiver failure, it shall transmit reports on scheduled times or positions, on the frequency in use, preceded by the phrase TRANSMITTING BLIND DUE TO RECEIVER FAILURE. The aircraft station shall transmit the intended message, following this by a complete repetition. During this procedure the aircraft shall also advise the time of its next intended transmission. Page 23
When an aircraft is unable to establish communication due to airborne equipment failure it shall, when so equipped, select the appropriate SSR code to indicate radio failure. The transponder code selected in this situation is 7600. In addition the aircraft, when forming part of a controlled aerodrome traffic, shall keep watch for such instructions as may be issued by visual signs. (The type of these signs are mentioned in Air Law.) Other actions during communication failure When flying VFR in the event of communications failure and, if the aircraft can maintain VMC, land at the nearest suitable aerodrome and report arrival as expeditiously as possible. Approaching an airport the pilot should fly overhead at an altitude higher than the traffic altitude. Make visual signs to the airport control by switching lights on and off and by swinging the aircrafts wings. During this time the direction of wind and the runway in use could be available to the pilot by monitoring other traffic on the circuit. Always look out for visual signs by the airport that notice you it is safe to land. Page 24
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Chapter 3 Radio Techniques and Phraseology Page 26
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Standardized R/T procedures are essential in aviation. Many accidents have been caused because operators did not follow the standard procedures and radio messages where misunderstood or missed. 3.1 Transmitting Your transmissions are more likely to be understood if you follow some simple rules: Before transmitting listen out to the frequency to ensure there will be no interference with a transmission from another station. Be familiar with good microphone operating techniques. Use a normal conversational tone. Maintain an even rate of speech. (About 100 words/min.) When it is known that the recipient will write down the message, speak a little slower. A slight pause before and after numbers make them easier to understand. Avoid using hesitation sounds. Press the push to talk button fully before speaking and don t release it until the message is complete. Page 27
The stuck microphone An irritating and potentially dangerous situation in R/T is a stuck microphone button. If the transmission button is held or stuck down the frequency becomes unusable by other traffic. For this reason always ensure that the button is released and the transmission is stopped. On most radio stations a sign with the letter T is appearing when the radio transmits. This is a good way to check you are not in a stuck microphone situation. 3.2 Transmission of time When transmitting time only the minutes of the hour are normally transmitted, unless there is any possibility of confusion. Coordinated Universal Time (UTC) shall be used. TIME TRANSMITTED AS PRONOUNCED AS 0803 ZERO THREE or ZERO EIGHT ZERO ZE-RO TREE or ZE-RO AIT ZE-RO TREE THREE 1300 ONE THREE ZERO ZERO WUN TREE ZE-RO ZE-RO 2057 FIVE SEVEN or TWO ZERO FIVE SEVEN FIFE SEV-en or TOO ZE-RO FIFE SEV-en Pilots may check the time with the appropriate ATS unit by transmitting TIME CHECK. Page 28
3.3 Transmission of letters Page 29
3.4 Transmission of numbers Page 30
3.5 Transmission of frequencies Frequency Transmitted as Pronounced a 118.125 One One Eight Decimal One Two Five 119.050 One One Nine Decimal Zero Five Zero WUN WUN AIT DAY SEE MAL WUN TOO FIFE WUN WUN NINER DAY SEE MAL ZERO FIFE ZERO 122.500 One Two Two Decimal Five 118.000 One One Eight Decimal Zero WUN TOO TOO DAY SEE MAL FIFE WUN WUN AIT DAY SEE MAL ZERO Page 31
3.6 Standard words & phrases Page 32
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3.7 Call signs Call signs for aeronautical stations Service Area Control Radar (in general) Approach Control Aerodrome Control Approach Control Radar Arrival/Departure Ground Movement Control Military Traffic Zone (MATZ) Crossing Precision Approach Radar Flight Information Air/Ground Communication Service Clearance Delivery Suffix CONTROL RADAR APPROACH TOWER DIRECTOR/DEPARTURE (RADAR when tasks combined) ARRIVAL (when approved) GROUND ZONE TALKDOWN INFORMATION RADIO DELIVERY Page 34
Call signs for aircraft When establishing communication, an aircraft shall use the full callsigns of both stations. After satisfactory communication has been established and provided that no confusion is likely to occur, the ground station may abbreviate callsigns (see table below). The pilot may only abbreviate the callsign of his aircraft if it has first been abbreviated by the aeronautical station. Page 35
Full Callsign GBFRM Speedbird GBGDC N31029 N573DA Midland 640 (Type C callsign) Piper GBSZT SX-ARD Abbreviation G-RM Speedbird DC N029 N3DA No abbreviation Piper ZT S-RD 3.8 Continuation of communications The placement of the callsigns of both the aircraft and the ground station within an established RTF exchange should be as follows: Ground to Air: Aircraft callsign message or reply. Air to Ground: a) Initiation of new information/request etc. Aircraft callsign then message; b) Reply Repeat of pertinent information/readback/acknowledgement then aircraft callsign. Page 36
When it is considered that reception is likely to be difficult, important elements of the message should be spoken twice. If there is a doubt that a message has been correctly received, a repetition of the message shall be requested either in full or in part using the phrase SAY AGAIN. Page 37
3.9 Transfer of communications To transfer communications with an aircraft to another unit, controllers shall pass instructions giving: a) The identity of the unit to be contacted; b) The frequency to be used for contact. Transfer of communication instructions should be passed in a single message. Items which require a read-back should normally be passed in a separate transmission before transfer. If no further communication is received from the pilot after an acknowledgement, satisfactory transfer of communication may be assumed. An aircraft will normally be advised by the appropriate aeronautical station to change from one radio frequency to another in accordance with agreed procedures. In the absence of such advice, the aircraft shall notify the aeronautical station before such a change takes place. Aircraft flying in controlled airspace must obtain permission from the controlling authority before changing frequency. 3.10 Clearance Issue and Read Back Requirements Provisions governing clearances are contained in the PANS-ATM (ICAO Doc 4444). A clearance may vary in content from a detailed description of the route and levels to be flown to a brief standard instrument departure (SID) according to local procedures. Controllers will pass a clearance slowly and clearly since the pilot needs to write it down; wasteful repetition will thus be avoided. Whenever possible, a route clearance should be passed to an aircraft before start up and the aircraft s full callsign will always be used. A route clearance and local departure instructions shall not be passed Page 38
in the same transmission. When a route clearance is passed subsequent to local departure instructions, or to an aircraft that is already airborne, tactical restrictions that remain in place shall be reiterated to ensure that the immediate profile to be flown by the pilot is unambiguous. Generally, controllers will avoid passing a clearance to a pilot engaged in complicated taxiing maneuvers and on no occasion when the pilot is engaged in line up or take-off maneuvers. An ATC route clearance is NOT an instruction to take-off or enter an active runway. The words 'TAKE-OFF' are used only when an aircraft is cleared for take-off. At all other times the word 'DEPARTURE' is used. The stringency of the read back requirement is directly related to the possible seriousness of a misunderstanding in the transmission and receipt of ATC clearance and instructions. ATC route clearances shall always be read back unless otherwise authorized by the appropriate ATS authority in which case they shall be acknowledged in a positive manner. Read backs shall always include the aircraft callsign. The ATS messages listed below are to be read back in full by the pilot/driver. If a readback is not received the pilot/driver will be asked to do so. Similarly, the pilot/driver is expected to request that instructions are repeated or clarified if any are not fully understood. Page 39
1) Taxi/Towing Instructions 2) Level Instructions 3) Heading Instructions 4) Speed Instructions 5) Airways or Route Clearances 6) Approach Clearances 7) Runway-in-Use 8) Clearance to Enter, Land On, Take-Off On, Backtrack, Cross, or Hold Short of any Active Runway 9) SSR Operating Instructions 10) Altimeter Settings 11) VDF Information 12) Type of ATS Service 13) Frequency Changes 14) Transition Levels If at any time a pilot receives a clearance or instruction with which he cannot comply, he should advise the controller using the phrase 'UNABLE' (COMPLY) and give the reason(s). 3.11 Test Transmissions All radio transmissions for test purposes shall be of the minimum duration necessary for the test and shall not continue for more than 10 seconds. The recurrence of such transmissions shall be kept to the minimum necessary for the test. The nature of the test shall be such that it is identifiable as a test transmission and cannot be confused with other communications. To achieve this the following format shall be used: The callsign of the aeronautical station being called; The aircraft identification; The words 'RADIO CHECK'; The frequency being used; Page 40
The operator of the aeronautical radio station being called will assess the transmission and will advise the aircraft making the test transmission in terms of the readability scale (Table below), together with a comment on the nature of any abnormality noted (i.e. excessive noise) using the following format: 'the aircraft identification'; 'the callsign' of the aeronautical station replying; 'READABILITY x' (where 'x' is a number taken from Table 11); 'additional information' with respect to any noted abnormality; NOTE: For practical reasons it may be necessary for the operator of an aeronautical station to reply with 'STATION CALLING (frequency or 8.33 channel) UNREADABLE'. Readability Scale Meaning 1 Unreadable 2 Readable now and then 3 Readable but with difficulty 4 Readable 5 Perfectly Readable Page 41
3.12 Routine Position Reports Position reports, formally called AIREPs, are required unless either the AIP or the ATS unit permit the pilot to omit them. Position reports contain the following elements of information, except that the last three may be omitted when prescribed on the basis of regional air navigation agreements. Aircraft identification Position Time Level Next position and time over Ensuing significant point Page 42
When transmitting time, only the minutes should normally be required. Each digit should be pronounced separately. The hour should be included when any possibility of confusion is likely to arise. 3.13 Automatic Terminal Information Service (ATIS) To keep down the RT traffic at busy aerodromes routine arrival and departure information is broadcast on a dedicated frequency or on an appropriate VOR frequency. Pilots inbound or requesting departure are normally required on first contact to ensure the receipt of these messages by quoting the code letter of the broadcast. ATIS is usually updated every 30 minutes following the weather observations taken at 20 or 50 minutes past the hour. ATIS will include the following: Aerodrome name ATIS identification letter (A to Z with A being the first broadcast) Time of weather observation Type of approach to be expected and RWY in use Runway condition, if appropriate Holding delay, if appropriate Transition level, if applicable Other essential operational information Page 43
Surface wind in magnetic degrees and knots Visibility and RVR if applicable in kilometers or meters Present weather (e.g. Precipitation) Cloud amount below 5000ft and height of cloud base in feet or CAVOK Air and Dew Point temperature in degrees Celsius QNH altimeter settings Any available information on phenomena in the approach or climb out areas Trend type forecast if available (e.g. NOSIG, TEMPO) Specific ATIS instructions The term CAVOK is used in terms of visibility, weather and cloud provided that: Visibility is 10 kilometers or more There is no cloud of operational significance No significant weather phenomena is present Page 44
Chapter 4 Aerodrome Control of Aircraft Page 46
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4.1 Pre Start Procedures Where no ATIS is provided the pilot may ask for current aerodrome information before requesting start up. It is normal to all but the smallest airports to request a Start-up clearance. Along with this request the location of the aircraft and ATIS information if available should be stated. Page 47
4.2 Taxi Instructions Taxi instructions issued by a controller will always contain a clearance limit, which is the point at which the aircraft must stop until further permission to proceed is given. When it is required to cross an active runway the aircraft is not permitted to cross unless it is cleared by the controller. When passing the runway the pilot should transmit CROSSING and when the aircraft vacates the runway the pilot should transmit VACATED. Page 48
4.3 Take-Off Procedures Since misunderstandings in the granting and acknowledgement of take-off clearances result in serious consequences, care should be taken to ensure that the phraseology employed during the taxi maneuvers cannot be interpreted as a take-off clearance. An aircraft should never transmit the phrase TAKE-OFF unless the controller issues a clearance for take-off for the particular aircraft. The word DEPARTURE should be used instead. Page 49
If an aircraft is cleared for an immediate take-off it is expected to take-off without delay, a rolling take-off. Page 50
Local departure instructions may also be given as part of the take-off clearance. Page 51
When the aircraft has started the take-off roll, and ATC consider it necessary for the aircraft to abandon take-off, the aircraft should be instructed to STOP IMMEDIATELLY twice. The aircraft should respond STOPPING. Page 52
If the take-off is abandoned by the pilot, the ATC should be informed as soon as practicable by calling REJECTED TAKE-OFF. Page 53
4.4 In the Circuit Requests for circuit joining procedures should be made in sufficient time to allow for a planned entry into the circuit, taking other traffic into account. When the traffic circuit is a right-hand pattern, it should be specified either in the AIP or by the ATC. Page 54
Depending on the prevailing traffic and the direction from which an aircraft is arriving, it may be requested to execute a straight-in approach. Page 55
The pilot having joined the traffic circuit makes routine reports as required by local procedures. It may be necessary to issue delaying or expediting instructions in order to co-ordinate traffic in the circuit. Page 56
4.5 Final Approach and Landing A FINAL report is made when an aircraft turns onto final within 4 NM from touchdown. If the aircraft is at a greater distance, a LONG FINAL report is made at about 8 NM from touchdown. Runway in use should always be read back after the landing clearance. In order to save taxiing time when flying training in the traffic circuit pilots may request to carry out a TOUCH AND GO during which the aircraft lands, continues rolling and takes off, without stopping. Page 57
4.6 Go Around When a missed approach is initiated cockpit workload is inevitably high. Any transmissions to aircraft going around should be brief and kept to a minimum. Unless otherwise instructed an aircraft operating VFR will continue in the normal traffic circuit. If the pilot initiates the missed approach the phrase GOING AROUND is used. Page 58
If ATC require a go around they will use the instruction GO AROUND twice. Page 59
4.7 After Landing Unless absolutely necessary, controllers should not direct taxi instructions to pilots until the landing roll is complete. Pilots should remain on tower frequency when clear of runway unless otherwise advised. Page 60