Nolan_Chapter_4.pdf

Airport Air Traffic Control Communications / 191 The safe operation of the nation’s air traffic control system ultimately depends on reliable and accurate communication between pilots and air traffic controllers. Virtually every instruction, procedure, or clearance used to separate or assist aircr...

Airport Air Traffic Control Communications / 191 The safe operation of the nation’s air traffic control system ultimately depends on reliable and accurate communication between pilots and air traffic controllers. Virtually every instruction, procedure, or clearance used to separate or assist aircraft relies on written or verbal communication. Any miscommunication between participants in the air traffic control system might contribute to or even be the direct cause of an aircraft accident with a subsequent loss of life. For this reason, proper and correct communications procedures must be observed by both pilots and controllers. Many of the accidents and incidents that have occurred over the last fifty years can be attributed to improper or misunderstood communications. Although many improvements to the air traffic control communications system have made it less reliant on verbal or written communication, pilots and controllers will continue to rely on human communication well into the twenty-first century. Thus, controllers must possess a proper understanding of communications procedures and phraseology. American pilots and controllers are fortunate that the International Civil Aviation Organization (ICAO) has designated English as the international language for ATC communications worldwide. This standard reduces the number of words and communications procedures that American controllers need to learn. However, air traffic controllers should realize that although foreign pilots are able to communicate using English, they probably do not have full command of the language. Thus, phraseology and slang not approved by ICAO or the FAA should never be used when communicating with foreign pilots. It is also recommended that standard phraseology be used when communicating with American pilots or controllers. Using standard procedures will help reduce the risk of miscommunication. Radio Communication Ever since radio communications equipment was installed in the Cleveland, Ohio control tower in 1936, radio has become the primary means of pilot– controller communication in the U.S. air traffic control system. Although the type of radio equipment has since changed, the basic principles of radio communication remain the same today. Simplex versus Duplex The earliest type of radio communication used in the air traffic control system was one way. Controllers could communicate with pilots, but not vice versa. Since the required radio equipment in those early years was quite bulky and heavy, airlines were reluctant to install both a navigation receiver and a communications transmitter on each aircraft. Thus, most aircraft were equipped only with a navigation receiver. Ground-based navaids were eventually modified to permit controllers to transmit instructions using the navigation aid frequencies. At first, this communication rendered the navaid useless while the controller was transmitting, 192 / CHAPTER 4 but later advances permitted the controller to transmit using the navaid while still allowing the pilot to use the ground station for navigation. As the benefits of radio communication became increasingly evident, aircraft operators chose to add transmitting equipment to their planes. The equipment operated on a different set of frequencies to eliminate any possible interference with the ground-based navaids. This development created its own set of problems, however. The addition of a separate transmitter and receiver markedly increased the weight of the aircraft, and adding separate transmitters and receivers in each control tower required an additional expenditure. Furthermore, during the transition from the navaid-based communication system, aircraft not equipped with transceivers would be unable to communicate with the control towers. An interim solution was to install receiving equipment in the control towers and transmitting equipment in the aircraft. This system still used the ground-based navaids for tower-to-aircraft communication but used the newly installed radios for aircraft-to-tower communication. To eliminate navaid interference, the aircraft transmitters used a different frequency from that used by the ground-based navaids. This two-frequency system is known as duplex communications (see Figure 4–1). Duplex was used in the air traffic control system for many years and is still used in some parts of the United States. In particular, FAA flight service stations are usually equipped to receive on one frequency while transmitting to the aircraft over a local VORTAC. The duplex system has disadvantages, however, that spurred the development of a radio system that would permit pilots Separate frequency Transmitter Figure 4–1. Duplex transmission principles. Receiver Airport Air Traffic Control Communications / 193 Same frequency Transmitter/receiver Figure 4–2. Simplex transmission principles. to communicate with controllers using one discrete frequency. This system was finally implemented within the ATC system and is known as simplex communications (see Figure 4–2). For the most part, every ATC facility in the United States relies primarily on simplex communications. Frequency Assignments Various international agreements allocate certain radio frequency bands for use in aeronautical communications. These frequency bands exist primarily in the high (HF), very high (VHF), and ultra-high (UHF) spectrums. High frequencies are primarily used for long-range communication, since these frequencies are not line of sight and can follow the curvature of the Earth. Only a few ATC facilities, such as ARTCCs with oceanic responsibility, find a need to use these frequencies. Most U.S. ATC facilities use both VHF and UHF for routine air-to-ground communication. UHF radio equipment is primarily used by military aircraft, whereas VHF is used by both military and civilian aircraft. The frequencies used in ATC communications are assigned by the Federal Communications Commission (FCC) in cooperation with the FAA. Since there is not a sufficient number of available frequencies in either the VHF or UHF spectrum to permit every ATC facility to operate using a separate frequency, the FCC often assigns the same frequency to two or more ATC facilities. Because the radio transmissions from high-altitude aircraft travel farther than those from low-flying aircraft, the FCC must carefully determine any potential interference problems before assigning these frequencies. 194 / CHAPTER 4 To simplify the task of assigning frequencies, the FCC has assigned these blocks of VHF bands for the following uses: Radio Operation Frequencies Use 108.000–117.950 Navigation aids 118.000–121.400 Air traffic control 121.500 Emergency search and rescue 121.600–121.925 Airport utility and ELT test 121.950 Aviation instructional and support 121.975 FSS private aircraft advisory 122.000–122.050 En route flight advisory service (EFAS) 122.075–122.675 FSS private aircraft advisory 122.700–122.725 UNICOM 122.750 Aircraft air-to-air 122.775 Aviation instruction and support 122.800 UNICOM 122.825 Domestic VHF 122.850 Multicom 122.875 Domestic VHF 122.900 Multicom 122.925 Multicom 122.950 Unicom 122.975–123.000 Unicom 123.050–123.075 Unicom 123.100 Aeronautical search and rescue 123.125–123.275 Flight test stations 123.300 Aviation support 123.325–123.475 Flight test stations 123.500 Aviation support 123.525–123.575 Flight test stations 123.600–123.650 FSS air carrier advisory 123.675–128.800 Air traffic control 126.200 Air traffic control (military common) 128.825–132.000 Domestic VHF (operational control) 132.025–136.975 Air traffic control Most air traffic controllers use radio equipment to perform their ATC duties. This equipment may be either fairly simple or very complex, depending on the capabilities of the facility. In general, each controller is assigned one or more radio frequencies for communications with pilots and has access to telephone equipment that permits communication with other controllers in the same Airport Air Traffic Control Communications / 195 facility or in adjacent facilities. The design of the voice switching system installed in most ATC facilities is sophisticated enough to permit such communication effortlessly. Most controllers are outfitted with a boom mike and headset assembly that permits them to move freely around the facility while still remaining in contact with the pilots. Other controllers may use standard microphones and speakers or telephone handsets provided by the local telephone company (which is known throughout the FAA by the generic term TELCO). Each controller has a switching panel to choose whether to communicate with other controllers or to the pilot over the radio. The system is designed so that when the controller is communicating on one particular channel, any message sent to him or her on either the radio or another landline is routed through an overhead speaker. Most facilities are equipped such that every frequency assigned to that facility can be used by any controller there. Standard Phraseology for Verbal Communications To ensure that miscommunication is kept to a minimum, it is imperative that controllers use the standard phraseology and procedures that have been recommended by ICAO and the FAA. When communicating with pilots or other controllers, a controller should always use the following message format: 1. Identification of the aircraft or controller being contacted. This serves to alert the intended receiver of the upcoming transmission. 2. Identification of the calling controller. This serves to identify who is initiating the communication. 3. The contents of the message. The message format should conform to standards approved by the FAA. 4. Termination. In communications with another ATC facility, the message should be terminated with the controller’s assigned operating initials. This procedure simplifies identification of the controller if a subsequent investigation is necessary. Certain letters and numbers may sound similar to each other when spoken over low-fidelity radio or telephone equipment. In addition, accents and dialects may make it difficult to discern and identify the exact content of a message. To alleviate this problem, a standard for pronunciation of letters and numbers has been approved by ICAO and adopted by the FAA. This standard is presented in Table 4–1. The standardized pronunciations should be used by controllers whenever communicating with pilots or other controllers. Air traffic controllers should also use the following standardized phraseology when passing along control instructions or various information to pilots or to other controllers. Numbers Each number should be enunciated individually unless group form pronunciation is stipulated. For example: Number Group Form Pronunciation Individual Pronunciation 1 One One 10 Ten One zero 196 / CHAPTER 4 Table 4–1. Standard Phraseology for Numbers and Letters Character Word Pronunciation 0 Zero Zee-ro 1 One Wun 2 Two Too 3 Three Tree 4 Four Fow-er 5 Five Fife 6 Six Six 7 Seven Sev-en 8 Eight Ait 9 Nine Nin-er A Alpha Al-fah B Bravo Brah-voh C Charlie Char-lee D Delta Del-ta E Echo Eck-oh F Foxtrot Foks-trot G Golf Golf H Hotel Hoh-tell I India In-dee-ah J Juliett Jewlee-ett K Kilo Key-loh L Lima Lee-mah M Mike Mike N November Nov-em-ber O Oscar Oss-cah P Papa Pah-pah Q Quebec Key-beck R Romeo Row-me-oh S Sierra See-air-ah T Tango Tang-go U Uniform You-nee-form V Victor Vik-tah W Whiskey Wiss-key X X-ray Ecks-ray Y Yankee Yang-key Z Zulu Zoo-loo Airport Air Traffic Control Communications Number Group Form Pronunciation Separate Pronunciation 15 Fifteen One five 132 One thirty-two One three two 569 Five sixty-nine Five six niner / 197 Unless otherwise specified, when serial numbers are pronounced, each digit should be enunciated individually. Altitudes Unless otherwise specified, every altitude used in the ATC system is measured above mean sea level (MSL). The only routine exception is cloud ceilings, which are measured above ground level (AGL). A controller who must issue an AGL altitude to a pilot should advise the pilot that the altitude is above ground level. Altitudes should be separated into thousands and hundreds, and the thousands should be pronounced separate from the hundreds. Each digit of the thousands number should be enunciated individually, whereas the hundreds should be pronounced in group form: Altitude Pronunciation 3,900 Three thousand niner hundred 12,500 One two thousand five hundred 17,000 One seven thousand Flight Levels Flight levels should be preceded by the words “flight level,” and each number should be enunciated individually: Flight Level Pronunciation 180 Flight level one eight zero 390 Flight level three niner zero Minimum Descent or Decision Height Altitudes Minimum descent or decision height altitudes published on instrument approach procedure charts should be prefixed with the type of altitude, and each number in the altitude should be enunciated individually: Altitude Pronunciation MDA 1,950 Minimum descent altitude one niner five zero DH 620 Decision height six two zero Time Since numerous ATC procedures require the use of time, a common system of time measurement is essential to the safe operation of the ATC system. The FAA and ICAO have agreed that local time is not to be used within the ATC system. Instead, every ATC facility around the world must use the same 198 / CHAPTER 4 GMT – 8 GMT – 7 GMT – 6 hours hours hours 9:00 A.M. 10:00 A.M. 11:00 A.M. Pacific standard time Pacific standard time meridian 120° Mountain standard time Mountain standard time meridian GMT – 5 hours 12:00 P.M. Central standard time Eastern standard time Central standard time meridian 105° 90° Eastern standard time meridian 75° Figure 4–3. Time zones across the United States. time standard, known as coordinated universal time (UTC). UTC is the same as local time in Greenwich, England, which is located on the 0° line of longitude, also known as the prime meridian. UTC was previously known as Greenwich mean time (GMT). The use of UTC around the world eliminates the question of which time zone a facility or aircraft is located in (see Figure 4–3). In addition, UTC eliminates the need for “a.m.” and “p.m.” by using a 24-hour clock system. UTC is always issued as a four-digit number, and the word “o’clock” is never pronounced. The conversion from a 12-hour clock to a 24-hour clock is fairly simple: Any time that has fewer than four digits should be prefixed with a zero. Any time between midnight and noon (a.m.) is not converted to a 24-hour clock. Any time between noon and midnight (p.m.) always has twelve hours added to it to differentiate it from a.m. time. For example, 6:20 a.m. becomes 0620, and 6:20 p.m. becomes 1820. Local time is converted to UTC by either adding or subtracting the number of hours indicated in the following chart: Airport Air Traffic Control Communications Time Zone Difference Eastern standard time (EST) 5 hours Eastern daylight time (EDT) 4 hours Central standard time (CST) 6 hours Central daylight time (CDT) 5 hours Mountain standard time (MST) 7 hours Mountain daylight time (MDT) 6 hours Pacific standard time (PST) 8 hours Pacific daylight time (PDT) 7 hours Alaskan standard time (AST) 9 hours Alaskan daylight time (ADT) 8 hours / 199 To convert from local time to UTC, convert the local time to a 24-hour clock, and then add the required time difference. To convert from UTC to local time, subtract the difference and convert from a 24-hour to a 12-hour format. For example: 4:35 a.m. (EST) is 0435 (EST), which is 0935 (UTC) 9:13 p.m. (PDT) is 2113 (PDT), which is 0413 (UTC) 1125 (UTC) is 0425 (MST), which is 4:25 a.m. (MST) To prevent any confusion when issuing time to the pilot, the controller should suffix any UTC time with the word “zulu” and any local time with the word “local.” Any issuance of time should also be preceded by the word “time.” When issuing time, the controller should enunciate each digit individually: Time (12-hour clock) Time (24-hour clock) Pronunciation 6:20 a.m. 0620 Time zero six two zero zulu 1:35 p.m. 1335 Time one three three five zulu Altimeter Settings The pilot must be issued the proper barometric pressure so that the aircraft’s altimeter can be properly adjusted to indicate altitude above mean sea level. The controller should issue these altimeter settings by individually enunciating every digit without pronouncing the decimal point; the altimeter setting should be preceded by the word “altimeter”: Altimeter Setting Pronunciation 29.92 Altimeter two niner niner two 20.16 Altimeter two zero one six Care should be taken when issuing altimeter settings to foreign pilots. Pilots from countries that have converted to the metric system no longer measure barometric pressure in inches of mercury but in millibars. It is the foreign pilot’s responsibility to convert the issued altimeter setting to millibars or to request a metric altimeter setting from the controller. Qualimetrics, Inc. 200 / CHAPTER 4 Figure 4–4. A digital wind direction and velocity indicator. Figure 4–5. An analog wind direction and velocity indicator. Wind Direction and Velocity Wind direction at airports is always determined in reference to magnetic north and indicates the direction that the wind is blowing from. The direction is always rounded off to the nearest 10°. Thus, a wind blowing from north to south is a 360° wind; a wind from the east is a 90° wind. The international standard for measuring wind velocity requires that wind speeds be measured in knots; 1 knot equals approximately 1.15 miles per hour. Wind direction and velocity information is always preceded by the word “wind,” with each digit of the wind direction enunciated individually. The wind direction is then followed by the word “at” and the wind velocity in knots, with each digit enunciated individually. If the wind measurement devices (see Figures 4–4 and 4–5) are inoperative, the wind speed and direction are preceded by the word “estimated.” If the wind direction is constantly changing, the word “variable” is suffixed to the average wind direction. If the wind velocity is constantly changing, the word “gusts” and the peak speed are suffixed to the wind speed. Here are some examples: Wind Direction Wind Speed Pronunciation From the north 15 knots Wind three six zero at one five From the east 10 knots with occasional gusts to 25 knots Wind zero niner zero at one zero gusts to two five Variable from the southeast 12 knots with occasional gusts to 35 knots Wind one five zero variable at one two gusts to three five Airport Air Traffic Control Communications / 201 Wind Direction Wind Speed Pronunciation Estimated from the southwest Estimated at 15 knots Estimated wind two three zero at one five Headings Aircraft headings are also measured in reference to magnetic north. If the heading contains fewer than three digits, it should be preceded by a sufficient number of zeros to make a three-digit number. Aircraft headings should always be preceded by the word “heading,” with each of the three digits enunciated individually. Here are some examples: Heading Pronunciation 005° Heading zero zero five 090° Heading zero niner zero 255° Heading two five five Runway Numbers Runways are also numbered in reference to their magnetic heading. The runway’s number is its magnetic heading rounded to the nearest 10° with leading and trailing zeros removed. For example, a runway heading north would have a magnetic heading of 360°. Dropping the trailing zero makes this runway number 36. Since the other end of the runway heads the opposite direction (south, which is a heading of 180°), it is runway 18. Each digit of a runway number is enunciated individually. Runway designations are always prefixed with the word “runway,” followed by the runway number and a suffix, if necessary. For example: Runway Heading Runway Number Pronunciation 090° 9 Runway niner 261° 26 Runway two six 138° 14R Runway one four right 14C Runway one four center 14L Runway one four left If two or three runways are constructed parallel to each other, the suffixes L for “left,” R for “right,” and C for “center” are used to differentiate the runways from one another (see Figure 4–6). If there are four or more parallel runways, some may be given a new number fairly close to their magnetic heading such as the Los Angeles International Airport, which has four parallel runways numbered 25L, 25R, 24L, and 24R. Radio Frequencies When issuing radio frequencies, the controller should enunciate each digit individually. Current VHF communications radios use 25 kHz spacing between assigned frequencies. For instance, the next usable frequency above 119.600 is 119.625, followed by 119.650, 119.675, and 119.700. The first number after the decimal is always pronounced, whether or 202 / CHAPTER 4 23 N 272° 269° 48 ° 9R 089° 27L 27C 22 8° 9C 092° 273° 27R 9L 093° 5 Figure 4–6. Runway numbering. not it is a zero. But if the second number after the decimal is a zero, it is not pronounced. The third number after the decimal is never pronounced, since it is always either a zero or a five and can be assumed. Low Frequency/Medium Frequency used by nondirectional beacons are always pronounced as whole numbers. VHF and UHF communication and navigation frequencies always use the decimal point. The decimal should be pronounced as “point.” For L/MF frequencies, the number should be suffixed with the word “kilohertz.” Here are some examples: Frequency Pronunciation 119.600 mHz One one niner point six 343.000 mHz Three four three point zero 123.050 mHz One two three point zero five 131.725 mHz One three one point seven two 401 kHz Four zero one kilohertz The FAA communications standard differs somewhat from that recommended by ICAO. Most ICAO member nations use the word “decimal” instead of “point.” For example, using ICAO procedures, 123.050 would be pronounced as “One two three decimal zero five.” MLS or TACAN Channels Microwave landing system and TACAN station frequencies are not issued explicitly. Channel numbers are used instead. MLS and TACAN channels are issued as two- or three-digit numbers, with each digit being enunciated individually. For example: Airport Air Traffic Control Communications Channel Pronunciation MLS channel 530 M-L-S channel five three zero TACAN channel 90 TACAN channel niner zero / 203 Speeds Aircraft speeds, like wind speeds, are always measured in knots. This occasionally causes some confusion with older general aviation aircraft equipped with airspeed indicators that indicate in miles per hour. Care should be taken when issuing speeds to small aircraft to ensure that the pilots realize that the requested airspeed is measured in knots. A rule of thumb is that an airspeed in miles per hour is about fifteen percent higher than the equivalent airspeed in knots. Thus, 100 knots is about 115 miles per hour. Airspeeds are always expressed with each digit being enunciated individually and suffixed with the word “knots,” as in the following examples: Speed Pronunciation 250 Two five zero knots 95 Niner five knots Air Traffic Control Facilities ATC facilities are identified by name, using the name of the city where the facility is located followed by the type of facility or the operating position being communicated with: Facility Type Pronunciation Local control Tower Ground control Ground Clearance delivery Clearance Air route traffic control center Center Flight service station Radio Approach control Approach Departure control Departure Flight watch Flight watch If a particular city has two or more airports, the airport name is used instead of the city name. Approach controls and centers are always named after the largest nearby city. Navy airports are always prefixed with “navy” to differentiate them from civilian facilities. Here are some examples: Lafayette Tower Chicago approach Indianapolis center Navy Glenview tower Terre Haute radio 204 / CHAPTER 4 Route and Navigation Aid Descriptions Airways are always described with the route identification pronounced in group form. The route number is prefixed with “victor” if it is a low-altitude airway or “jay” if it is a jet route. For example: Route Pronunciation V12 Victor twelve J97 Jay ninety-seven Radials that emanate from a VOR should be pronounced as a three-digit number with each digit being enunciated individually (similar to the way aircraft headings are pronounced). The radial number is prefixed with the VOR name and is always suffixed with the word “radial” (the word “degree” is never used when describing radials): Boiler one four three radial Indianapolis three six zero radial Champaign zero zero six radial Bearings from nondirectional beacons (NDBs) are expressed as magnetic bearings from the station and are suffixed with the station’s identifying name and the words “radio beacon” or “outer compass locator” as appropriate: Three five five bearing from the Pully radio beacon Two seven eight bearing from the Earle outer compass locator Intersections located along an airway are described using either (1) the fiveletter approved intersection name (found in FAA order 7350.5, “Location Identifiers”), or (2) the VOR radial and DME distance from the VOR. Here are some examples: Staks intersection Flite waypoint Boiler zero niner zero radial one two mile fix ATC Communications Procedures The communications procedures that should be used by air traffic controllers are detailed in the Air Traffic Control Handbook. Although individual circumstances may require modification of these procedures, adhering to them will help eliminate confusion and potential problems. Airport Air Traffic Control Communications / 205 The remainder of this chapter describes the most common phrases used by air traffic controllers, including how and when to use each phrase and some examples of proper phraseology. The terms may be used when communicating in writing as well as orally. To increase efficiency and conserve space when writing these phrases, standard operating procedure requires that controllers abbreviate them. The approved abbreviation appears in parentheses after each phrase. Clearance Any IFR or participating VFR aircraft operating within controlled airspace must be cleared (C) prior to participating in the ATC system. A clearance authorizes a pilot to proceed to a certain point or to perform a specific maneuver. When issuing a clearance or a control instruction, the controller must identify the aircraft, identify the ATC facility, and then issue the clearance or instruction. This instruction could be a clearance to take off or land, to perform an instrument approach procedure, or to proceed to an airport or navigational fix, as in the following examples: Phraseology Explanation United seven twelve runway two four cleared for takeoff. This authorizes the pilot to take off using runway 24. Beech eight delta mike, after departure, turn left and proceed direct to the Boiler VOR, runway one zero cleared for takeoff. This clearance directs the pilot to turn left after takeoff from runway 10 and proceed to the Boiler VOR. Delta one ninety-one, after departure turn right heading one two zero, runway three five cleared for takeoff. After departing runway 35, the pilot will turn right to a heading of 120°. American nine twenty-one cleared to land runway niner. This authorizes the pilot to make a full-stop landing on runway 9. Aztec seven eight one cleared for touch and go runway two three. A touch and go clearance permits the aircraft to land on the runway but take off again before actually coming to a stop. This maneuver is usually used by students practicing takeoffs and landings. Mooney three six charlie cleared for stop and go runway five. A stop and go clearance is similar to a touch and go except that the aircraft comes to a full stop on the runway prior to beginning its takeoff run. Sport zero two romeo cleared for low approach runway three two. In a low approach, the pilot approaches to land on the runway but does not actually make contact with the surface. Upon reaching the desired altitude, the pilot begins a climb and departs. 206 / CHAPTER 4 Phraseology Explanation Bellanca two bravo zulu cleared for the option runway two eight left. An option clearance permits the pilot to perform a landing, touch and go, stop and go, or low approach. The pilot does not typically inform the controller which option has been chosen. This maneuver is used in flight training to permit flight instructors to evaluate a student’s performance under changing conditions. King Air four papa uniform cleared for ILS runway one zero approach. This authorizes the pilot to conduct the published ILS approach for runway 10. This does not authorize landing on the runway. An additional clearance is necessary for landing. Queen Air seven tango yankee cleared for approach. This clearance authorizes the pilot to conduct any instrument approach procedure at the designated airport. The word “cleared” is also used when issuing IFR clearances to aircraft prior to departure. An IFR clearance must include the following items (those marked with an asterisk are not required in every clearance and are used only when necessary): 1. Aircraft identification 2. The word “cleared” 3. The clearance limit *4. Departure instructions 5. The route of flight 6. Altitude assignments *7. Holding instructions *8. Any additional information 9. Frequency and transponder code information Each of these items is discussed in detail in the following sections, with examples of the proper phraseology provided. Aircraft Identification Aircraft are identified using standard procedures that help eliminate confusion and misdirected instructions. It is vitally important that control information directed to one aircraft be received by the pilots of that aircraft. It is also exceedingly important that the controller be certain with which aircraft he or she is communicating. If the pilot of one aircraft were to follow the instructions issued to another or if the controller were unsure which aircraft had just made a position report, the air traffic control system would be unable to function properly. Airport Air Traffic Control Communications / 207 The assigned aircraft identification call signs used by pilots and controllers vary depending on the type of operation in which the aircraft is involved. If the aircraft is a scheduled airline flight operating under FAR 121 or 125, the FAA has authorized the use of a distinctive airline name that should be used when communicating with that aircraft. In addition to this name, every airline flight has been issued a flight number by the airline itself. The approved aircraft identification consists of the airline name, followed by the flight number, pronounced in group form (such as “Comair twenty-six eleven”). Most authorized airline names are easily recognizable, although a few are somewhat unusual. These approved airline names have been selected to ensure that no two sound similar. Every airline has also been issued a threeletter designator to be used in written communications concerning the aircraft. A list of air carrier names and their three-letter identifiers can be found in the Contractions Handbook published by the FAA. Here are some examples from the handbook. Airline Name FAA Indentifier Call Sign Aeromexico AMX Aeromexico Air Canada ACA Air Canada Air China CCA Air China Air France AFR Airfrans Aer Lingus EIN Shamrock Air Wisconsin AWI Air Wisconsin Alaska ASA Alaska American AAL American British Airways BAW Speedbird Cathay Pacific CPA Cathay China Eastern CES China Eastern Continental COA Continental Delta DAL Delta Emirates Airlines UAE Emirates Evergreen EIA Evergreen Federal Express FDX Fedex Frontier FFT Frontier Japan Air Lines JAL Japanair JetBlue JBU Jetblue KLM KLM KLM Mesa ASH Air Shuttle Mexicana MXA Mexicana Midwest MEP Midex Net Jets NJT Netjet Piedmont PDT Piedmont 208 / CHAPTER 4 Airline Name FAA Indentifier Call Sign Republic RPA Brickyard Ryanair RYR Ryanair Southwest SWA Southwest Spirit Airlines NKS Spiritwings United Airlines UAL United United Parcel UPS UPS US Airways USA Cactus Virgin America VRD Redwood Virgin Atlantic VIR Virgin WestJet WJA Westjet General aviation aircraft call signs consist of the type of aircraft plus a unique serial number assigned by the FAA. The call sign may contain up to five numbers or letters. The approved aircraft type can be found in Appendix B of FAAH7110.65. When the call sign is pronounced, each character is enunciated individually. Every U.S. aircraft’s serial number is preceded by the letter N, signifying that it is registered in the United States. During routine communications, this letter is usually not pronounced but can be used if the pilot wishes. Aircraft registered in other countries have aircraft identification numbers or letters preceded with a different letter or series of letters. After initial communication has been established with aircraft, they may be identified using the last three characters of their assigned serial number if no confusion will result. In Table 4–2, these abbreviated call signs are enclosed in parentheses. If two aircraft have similar last three characters, the full call sign should be used to help eliminate any confusion. Table 4–2. General Aviation Aircraft Call Signals Aircraft Serial Number Aircraft Type Pronunciation N231PA Piper Cherokee Cherokee two three one papa alpha (Cherokee one papa alpha) N98556 Cessna Citation Citation niner eight five five six (Citation five five six) N5102R Beech Sport Sport five one zero two romeo (Sport zero two romeo) CF-AMG Dassault Falcon Falcon C-F-A-M-G (Falcon A-M-G) Airport Air Traffic Control Communications / 209 General aviation aircraft being used for special purposes are permitted to use special call sign prefixes that identify their mission. These approved prefixes are found in the FAA handbook. Here are some examples: Type of Operation Prefix Phraseology Air ambulance Lifeguard Lifeguard Cessna two five one lima november Air taxi Tango Tango Aztec niner niner three five eight Military aircraft are assigned a variety of call signs that may include five numbers, one word followed by numbers, or two letters followed by numbers. Each word is pronounced in full with the letters and numbers enunciated individually. The aircraft’s call sign is always prefixed with the name of the military service, as in the following examples: Call Sign Military Service Pronunciation R23956 Army Army two three niner five six VV1963 Navy Navy one niner six three A14932 Air Force Air Force one four niner three two CAF95 Canadian Canadian niner five The approved identification prefixes (found in FAAH 7110.65) are as follows: Prefix Military Service A U.S. Air Force C U.S. Coast Guard CAF Canadian Armed Force CAM Canadian Armed Force (Transport Command) CTG Canadian Coast Guard E Medical Air Evacuation F Flight Check G National Guard L LOGAIR (USAF civilian contract flight) M MAC (Military Airlift Command) R U.S. Army S Special Air Mission VM U.S. Marine Corps VV U.S. Navy To assist air traffic controllers in identifying military training flights that may require special handling, flights being piloted by students can be suffixed with the letter Z (“zulu”). 210 / CHAPTER 4 Presidential aircraft have been assigned call signs that alert controllers that special handling of the aircraft may be required. Anytime the president of the United States is aboard a military aircraft, the call sign becomes a combination of the military service name and the word “one” (such as “Air Force one,” “Marine one,” “Navy one”). If the president is aboard a civilian aircraft, the aircraft’s call sign becomes “Executive one.” If a member of the president’s family is on board an aircraft but the president is not, the call sign is suffixed with the letter F (“foxtrot”). An aircraft carrying the vice president is identified using a similar procedure but with the word “two” instead of “one.” Aircraft with the vice president’s family are identified using the “foxtrot” suffix. Destination Airport or Intermediate Fix It is preferable for the aircraft to be cleared to the pilot’s filed destination airport. This procedure enables the pilot to plan the entire flight and provides a route to the destination in case of radio failure. If the controller is unable to issue a clearance to the destination airport, the pilot should be cleared to an intermediate fix and then informed of the expected route. If a delay is likely at the intermediate fix, the pilot should be informed of the approximate time that may be spent holding at the fix. Departure Instructions Every departing IFR aircraft must be issued an initial route that will lead from the airport to the route contained in the clearance. This may be either a published SID route or a heading. The heading should be preceded by one of the following phrases: “turn right heading” (TR), “turn left heading” (TL), or “fly heading” (FH). When issued a “fly heading,” the pilot is expected to turn to the assigned heading in whatever direction that results in the shortest turn. This phraseology is normally used when the aircraft’s current heading is unknown. If the controller assigns a particular direction to turn (left or right), the pilot is required to turn in that direction, regardless of whether it will result in the shortest turn. Here are some examples: Pronunciation Written Version Cessna niner papa uniform, turn right heading three five zero N9PU TR 350 Midwest five six three, fly heading one one zero MEP563, FH 110 A departing aircraft must be assigned a heading to fly until the pilot intercepts the assigned airway or route of flight. Normally, the controller will assign the ⱖ pilot a heading to fly until the aircraft joins an airway, intercepts [ ] a course or radial, or can navigate direct [ D ] to the navaid. For example: Pronunciation United six eleven, turn right heading one five zero, join victor ninety-seven Republic twenty-five forty-one, fly heading two niner zero, join victor two fifty-one Written Version – UAL611 TR 150 ⬎ V97 – RPA2541 FH290 ⬎ V251 Kingair three papa uniform, fly runway N3PU FRH D heading until able direct the Kokomo VOR OKK Airport Air Traffic Control Communications Route of Flight Altitude Assignment / 211 The route of flight must consist of an airway, a series of airways, or a series of navaids that lead to the clearance limit. If the route issued to the pilot is exactly the same as the route filed in the IFR flight plan, the controller can substitute the phrase cleared as filed (CAF) instead. However, if the ATC facility at the departure airport is not equipped with radar, the first airway that will be used by the pilot should be appended to the “cleared as filed” clearance. This procedure ensures that even if a mistake has been made and the pilot flies a different route from what the controller expects, at least the initial route of flight will be correct. If there is a problem later on, it will occur in an area of radar coverage, where the error can be observed and easily corrected. If just a minor change is made to the pilot’s filed route of flight, the changed portion of the route should be issued, followed by the words “then as filed.” But if any major changes have been made to the pilot’s filed route of flight, the route portion of the IFR clearance should be prefixed with the phrase “unable routing requested.” This alerts the pilot that major changes have been made. Once the aircraft is in flight, if any part of the clearance needs to be amended, only the amended portion of the clearance should be issued to the pilot. Here are some examples. Pronunciation Written Version Comair seventeen fourteen, unable routing requested, cleared to the Chicago O’Hare Airport via direct Boiler, victor seven Chicago Heights, direct COM1714 D BVT V7 CGT Northwest two twenty cleared to the Los Angeles Airport as filed NWA 220 CAF LAX Beech eight delta mike cleared to the Chicago Midway Airport via direct Knox, then as filed N8DM D OXI CAF MDW Altitude assignments may be issued to pilots in a number of ways. The following phrases are used to clarify whether the pilot is to remain at a specific altitude or is permitted to climb and descend without the controller’s permission. Maintain Both IFR and participating VFR pilots are assigned an altitude at which they are required to fly. IFR pilots are required to maintain ( M ) this altitude, whereas VFR pilots must make every attempt to do so, but are permitted to change altitude to remain in VFR conditions. When IFR pilots are assigned a new altitude to maintain, they are required by FAR 91 to advise the controller when they depart their previously assigned altitude. Unless specifically requested, they are not required to report when they reach their newly assigned altitude. A clearance to maintain an altitude may be modified to include the prefixes “climb and” [↑] or “descend and” [↓]. These prefixes should be used 212 / CHAPTER 4 when requesting that an aircraft change from one altitude to another. Here are some examples of “maintain” phraseology: Pronunciation Written Version Sport zero two romeo, maintain three thousand N02R M 30 Eastern six fifty-six, climb and maintain niner thousand EAL656 c 90 Clipper six ninety, descend and maintain flight level three five zero PAL690 T 350 The word “maintain” may also be used when requesting that a pilot remain in certain weather conditions. If necessary, VFR pilots may be issued a clearance to maintain VFR. Since VFR pilots are not permitted by FAR 91 to fly IFR in controlled airspace without a clearance, this clearance is essentially advisory in nature. In essence, it reminds the pilot that an IFR clearance has not been issued or is no longer effective and that the aircraft must remain in VFR conditions. Controllers are not authorized to issue a “maintain VFR” clearance to aircraft operating under an IFR flight plan unless the pilot specifically requests it. A VFR clearance to an IFR aircraft is usually used whenever an IFR-rated pilot wishes to depart on an IFR clearance but upon reaching VFR conditions plans to cancel the IFR clearance and proceed VFR. In other circumstances, the pilot may want to remain on an IFR clearance but be authorized to maintain flight in VFR conditions and to deviate from the assigned altitude. The pilot does not wish to cancel the IFR clearance since it may be needed later in the flight. This type of flight is known as VFR on top. With this type of clearance, the pilot is authorized to change altitudes as long as VFR conditions can be maintained. A pilot desiring this type of clearance would be advised to “maintain VFR on top.” Such VFR clearance relinquishes the controller’s responsibility for separating this aircraft from other IFR aircraft. The pilot assumes the responsibility for remaining in VFR conditions and for seeing and avoiding other aircraft, both VFR and IFR. If a pilot requests that an IFR clearance be reissued at some time in the future, the controller must comply with the request as soon as possible and then assume IFR separation responsibility for that aircraft. Cruise A cruise clearance is used by air traffic controllers to authorize an IFR aircraft to operate at any altitude between the assigned altitude and the minimum IFR altitude. This clearance permits the pilot to level off and operate at any intermediate altitude within this assigned block of airspace. However, once the pilot begins to descend and verbally reports this descent to the controller, he or she may not return to any vacated altitude without additional ATC clearance. A “cruise” (S) clearance also authorizes the pilot to conduct any instrument approach procedure published for the destination airport. Cruise clearances are rarely used but may be assigned to aircraft approaching smaller, less busy airports that do not have operating air traffic control towers. Here Airport Air Traffic Control Communications / 213 is an example of the phraseology: “Cessna niner three uniform, cleared to the Champaign Airport, cruise six thousand” (N93U CMI S 60). Cross At There may be situations in which it is operationally advantageous to require an aircraft to cross a particular navigational fix at a predetermined altitude. When this is required, the controller requests that the pilot “cross” (X) the fix “at” (@), “at or above” (c), or “at or below” (T) a specified altitude. This procedure is used whenever it is critically important, either for separation or to comply with ATC procedures, that the aircraft meet the altitude restriction. Whenever a crossing restriction has been issued, the pilot may change altitude at any desired rate but must ensure that the crossing restriction is met. If the controller requires the pilot to change altitude at the aircraft’s optimal rate of climb or descent, the controller should precede the clearance with the phrase “descend now.” Pilot’s Discretion Whenever a new altitude is assigned, the pilot is expected to climb or descend at an optimal rate consistent with the aircraft’s performance. When the aircraft is within 1,000 feet of the assigned altitude, the pilot should attempt to decrease the climb or descent rate to approximately 500 feet per minute. The only exceptions to this procedure are when a crossing restriction has been issued and when the pilot is permitted to climb or descend at pilot’s discretion. If the phrase “at pilot’s discretion” (PD) is used by the controller in conjunction with an altitude assignment, the pilot is given the option of when to begin the climb or descent. When authorized to change altitude at pilot’s discretion, the pilot is permitted to level off at any intermediate altitude before reaching the assigned altitude but is not permitted to return to any altitude previously vacated. An altitude change in conjunction with pilot’s discretion gives the pilot the opportunity to fly the aircraft in the most efficient manner, saving both fuel and time. Here are some examples of phraseology: Pronunciation Explanation Air Force one five seven, descend at pilot’s discretion, maintain flight level two zero zero Air Force 157 may begin the descent at any point and at whatever rate the pilot wishes. The aircraft may level off at any intermediate altitude but must eventually descend to FL 200 and cannot return to any previously vacated altitude. Comanche five niner papa, descend and maintain three thousand, cross Vages at or below five thousand Comanche 59P may begin the descent at any point and at whatever rate the pilot wishes. The aircraft may level off at any intermediate altitude but must cross Vages at or below 5,000 feet. The aircraft must eventually maintain 3,000 feet and cannot return to any altitude previously vacated. 214 / CHAPTER 4 Required Reports Pronunciation Explanation Gulfstream eight november mike, climb and maintain flight level two five zero, cross Potes at one three thousand Gulfstream 8NM may climb at any rate up to FL 250 and may temporarily level off at any altitude but must cross the Potes intersection at 13,000 feet. Mooney eight mike november, descend now to four thousand, cross the Boiler VOR at or below six thousand Mooney 8MN must initiate a descent upon receipt of the clearance and must descend at an optimal rate for that aircraft. The aircraft must cross the Boiler VOR at or below 6,000 feet and must maintain 4,000 feet. The pilot may not temporarily level off at any intermediate altitude but may reduce the aircraft’s rate of descent to 500 feet per minute upon reaching 5,000 feet. The controller may request reports other than position and altitude from the pilot. A clearance may include requests to report crossing, reaching, or leaving. Report Crossing Following a report crossing (RX) request, the pilot will advise the controller when the aircraft crosses the requested fix or intersection. Examples of phraseology include the following: Falcon four two quebec, report crossing Staks (N42Q RX STAKS) King air four papa uniform, report crossing the Danville one two seven radial, three six mile fix (N4PU RX DNV 127/36) Report Reaching Following a report reaching (RR) request, the pilot will advise the controller when the aircraft has leveled off at the newly assigned altitude. For example: Dehavilland one six echo, climb and maintain seven thousand, report reaching (N16E c 70 RR) Fairchild, eight sierra victor, report reaching flight level one niner zero (M8SV RR 190) Report Leaving A report leaving (RL) clearance is used by the controller to require a pilot to report passing through any intermediate altitude. FAR 91 requires that every pilot advise the controller when leaving a previously assigned altitude but not when reaching an assigned altitude. “Report leaving” may be phrased as follows: Lear seven golf juliett, descend and maintain six thousand, report leaving flight level one niner zero, report leaving one one thousand (N7GJ T 60 RL190 RL 110) Airport Air Traffic Control Communications Holding Instructions / 215 If traffic conditions warrant, pilots may be cleared by air traffic controllers to enter a holding pattern. Holding patterns may be necessary when aircraft must remain clear of a specific controller’s area because of traffic saturation at the destination airport. Holding patterns require that the pilot fly a modified racetrack pattern in reference to a fix or a navaid. Holding patterns vary in size depending on the aircraft type and the holding altitude. Holding patterns are used primarily in areas without radar coverage. The proper application of holding patterns when separating aircraft is discussed in Chapter 7. The phraseology that air traffic controllers should use when issuing a holding instruction is as follows: 1. State the direction of holding from the fix. This is the location of the inbound course in relation to the holding fix or navigation aid. The direction of holding is issued using one of the eight points of the compass (“Cherokee two papa uniform, hold west”). 2. State the name of the holding fix to be used. This is the fix or the navigation aid that the aircraft will actually hold at. It can be a VOR, an NDB, an intersection of two VOR radials, an intersection of two NDB bearings, an intersection defined using a VOR radial and an NDB bearing, a DME fix, or any intersection that lies along the final approach course of an instrument approach (“of Boiler,” “of Staks,” “of the Boiler two seven zero radial, one two mile fix”). 3. State the radial, course, bearing, azimuth, or route on which the aircraft will hold (“on victor nine,” “on the two seven zero radial,” “on the one two three bearing to the Earle outer compass locator,” “on the localizer course”). 4. State the holding-pattern leg length in miles if DME or RNAV is to be used or in minutes if a nonstandard holding pattern is required. If this section is omitted in the clearance, the pilot will use a standard holding pattern, which is defined as a 1-minute inbound leg if holding is accomplished at or below 14,000 feet MSL or a 1½-minute inbound leg if holding is accomplished above 14,000 feet MSL (“two-minute legs,” “seven-mile legs”). 5. State the direction of the holding pattern turns if a nonstandard (left turn) holding pattern is necessary. If this phrase is omitted by the controller, the pilot is expected to use right turns while in the holding pattern (“Left turns”). 6. State the projected time (UTC) when the controller estimates that the pilot will be permitted to exit the holding pattern and continue on course. This is known as the expect further clearance (EFC) time. If radio communication between the pilot and the controller is lost, the pilot will depart the holding pattern and continue on course when the EFC time has passed. When the holding instructions are originally issued, the controller should also inform the pilot of the current UTC time (“Expect further clearance at one two five five zulu, time now one two zero five zulu”). Here are two examples of full holding messages (see Figures 4–7 and 4–8): Sport zero two romeo, hold west of the Earle outer compass locator on the localizer, two-minute legs, left turns, expect further clearance at zero niner zero zero, time now zero eight four five. 216 / CHAPTER 4 Localizer 2 min. Earle LOM Figure 4–7. Example of an aircraft holding west of the Earle LOM on the localizer course, using two-minute legs left turns. 323° Radial 1 min. BVT VOR Figure 4–8. Example of an aircraft holding northwest of the BVT VOR on the 323° radial. United six eleven, hold northwest of the Boiler VOR on the three two three radial, expect further clearance at one one two five zulu, time now one one zero five. Whenever the controller determines that the aircraft can be permitted to leave the holding fix and continue on course, the following procedure should be used: 1. Issue the new clearance limit. 2. Issue the route of flight to the clearance limit. If there has been no change in the route since the aircraft entered the holding pattern, the phrase “via last routing cleared” may be used. 3. Restate the assigned altitude. Airport Air Traffic Control Communications / 217 Here are examples of the proper phraseology: American six fifty-four is cleared to the Chicago O’Hare Airport via last routing cleared, maintain flight level one eight zero. Jetstream nine alpha victor is cleared to the Champaign VOR via direct the Danville VOR and victor two fifty-one, maintain five thousand. Whenever the aircraft has been cleared to leave the holding pattern, the pilot is expected to remain in the holding pattern until the aircraft crosses the holding fix, then proceed on course. The pilot is not expected to take any shortcuts. Additional Communications Phraseology When appended to a controller’s transmission, the word “acknowledge” requests that the pilot inform the controller that the message in question has been received: CONTROLLER: Cessna two mike november, cleared to land. Acknowledge. PILOT: Cessna two mike november understands cleared to land. The word “affirmative” means the same as “yes” but is more understandable when spoken over the radio. The word “negative” means the same as “no” but is more understandable when spoken over the radio. The term “say intentions” is a request for the pilot to advise the controller of his or her intentions after a maneuver is performed: CONTROLLER: Sport zero two romeo, say intentions after this touch and go. PILOT: Sport zero two romeo would like to depart to the east. When only one pilot is flying an aircraft, it is particularly helpful to the pilot to be given advance notice concerning instructions that might be received in a later clearance. Such instructions are preceded by the word “expect.” This information is used by the pilot for planning purposes in case of radio communication failure. Here are some examples: Jetstream seven bravo charlie cleared to the Danville Airport via victor two fifty-one. Climb and maintain six thousand. Expect the ILS runway one seven approach at Danville. Westwind six bravo victor, descend and maintain one zero thousand, expect lower altitude in five miles. 218 / CHAPTER 4 A variety of other standardized phrases and abbreviations are used by air traffic controllers while performing their duties. Some of the more common abbreviations are included in Table 4–3. Other phrases and abbreviations used by controllers can be found either in FAAH 7110.65 or in the facility directives. If all the communications procedures described in this chapter are used by both air traffic controllers and pilots, the risk of miscommunication and the resulting potential for an accident or incident can be significantly reduced. In light of this fact, air traffic controllers should routinely use standard communications techniques when conversing with pilots and other controllers, resisting the urge to use slang or CB radio language. Table 4–3. Some Standard ATC Abbreviations Abbreviation Meaning A Cleared to airport of intended landing B ARTCC clearance delivered BC ILS back course approach CAF Cleared as filed CT Contact approach D Cleared to depart from the fix F Cleared to the fix FA Final approach I Initial approach ILS ILS approach L Cleared to land MA Missed approach MLS MLS approach N Clearance not delivered NDB NDB approach O Cleared to the outer marker OTP VFR on top conditions PA Precision approach PD Pilot’s discretion PT Procedure turn Q Cleared to fly specified sectors of a navaid RH Runway heading