Nolan_Chapter_5.pdf

Air Traffic Control Procedures and Organization / 221 Separation Responsibilities in Controlled Airspace Michael Nolan The Federal Aviation Administration is designated, by act of Congress, as the federal agency with authority for the separation of both civilian and military aircraft within the...

Air Traffic Control Procedures and Organization / 221 Separation Responsibilities in Controlled Airspace Michael Nolan The Federal Aviation Administration is designated, by act of Congress, as the federal agency with authority for the separation of both civilian and military aircraft within the controlled airspace overlying the United States. To carry out this function, the FAA has divided the nation’s assigned airspace into twentyfour areas and assigned aircraft separation responsibility within these areas to twenty-four air route traffic control centers (ARTCCs) (see Figure 5–1). Personnel at each ARTCC have the ultimate responsibility for separating every IFR and participating VFR aircraft operating within controlled airspace. Nonparticipating aircraft or aircraft operating in uncontrolled airspace are not offered separation services. The basic function of the ARTCC is to separate aircraft traveling between airports. When a particular airport is congested and an FAA or military ATC facility is located at or near the airport, it is usually more efficient for the local ATC facility to be given responsibility for separating the aircraft operating in the immediate vicinity of the airport. If, after performing a study of the local airspace and traffic structure, the FAA determines that both safety and efficiency would be increased if the smaller facility were assigned responsibility for Figure 5–1. The Indianapolis ARTCC, typical of most ARTCC facilities. Michael Nolan 222 / CHAPTER 5 Figure 5–2. Indianapolis air traffic control tower. the airspace, the ARTCC usually delegates aircraft separation responsibility to that facility. If it is an FAA facility, it is usually either an air traffic control tower (ATCT) (see Figure 5–2) or a terminal radar approach control (TRACON). If it is a military facility, it is usually a control tower or a radar approach control (RAPCON). This transfer of separation responsibility from the ARTCC to the smaller facility is formally authorized through a letter of agreement (LOA). Such a letter between air traffic control facilities specifically declares: The physical dimensions of the airspace involved. The approved altitudes and airways used by aircraft that will cross the boundary between the two facilities. The procedures used by air traffic controllers when an aircraft progresses from one facility’s area of responsibility into the next. Letters of agreement are also established between adjacent ARTCCs and control towers that describe the boundaries of each facility’s area of responsibility and the procedures that should be used when aircraft cross this boundary (see Figure 5–3). Air Traffic Control Procedures and Organization / 223 FORT WORTH ARTCC AND HOUSTON ARTCC LETTER OF AGREEMENT Effective as of 7/6/02 PURPOSE: This agreement between Fort Worth Air Route Traffic Control Center (ZFW) and Houston Air Route Traffic Control Center (ZHU) covers coordination procedures and is supplementary to the procedures in the FAA Order 7110.65. CANCELLATION: Any and all previous LOAs between ZFW and ZHU are canceled. PROCEDURES: Houston shall ensure that: — Aircraft landing in the Dallas/Fort Worth terminal area and departing from the Houston terminal area and east portion of Houston ARTCC are cleared to Cedar Creek VORTAC (CQY) and cross the ARTCC boundary at or below FL 270. — Aircraft landing in the Dallas/Fort Worth terminal area and departing from the Austin terminal area and west portion of Houston ARTCC are cleared to Glen Rose VORTAC (CQY) and cross the ARTCC boundary at or below FL 230. Fort Worth shall ensure that: — Aircraft landing in the Houston terminal area and departing from the Dallas/Fort Worth terminal area are cleared to Navasota VORTAC (TNV) and cross the ARTCC boundary at or below FL 270. — Aircraft landing in the Austin terminal area and departing from the Dallas/Fort Worth terminal area are cleared to Centex VORTAC (CWK) and cross the ARTCC boundary at or below FL 190, descending to 11,000 ft. EXCEPTIONS: Deviations from the procedures established above may be made only after prior coordination and agreement between the parties involved. Signed, Houston ARTCC Chief Fort Worth ARTCC Chief Figure 5–3. Letter of agreement. 224 / CHAPTER 5 Air Traffic Control Procedures When separating aircraft, or when offering any additional ATC services, controllers must use the procedures found in the Air Traffic Control Handbook. This FAA handbook was based on guidelines published by the International Civil Aviation Organization (also known as ICAO annexes) but differs from them in some minor areas. FAA-certified air traffic controllers, whether working for the FAA or for another employer, are obligated by law to use the handbook procedures whenever they are performing air traffic control duties. Department of Defense (DOD) air traffic controllers use their own procedures, which differ somewhat from those used by FAA-certified controllers. In general, military air traffic control procedures are modeled after those contained in the FAA handbook but in some cases permit either the pilot or the controller less flexibility. Since some FAA controllers are assigned to military facilities and some DOD controllers separate civilian aircraft, the handbook contains both the FAA and military ATC procedures. The specific military procedures are described only if they differ from FAA-approved procedures. To eliminate confusion about which set of procedures to apply when separating aircraft, the FAA and the DOD have mutually agreed that: If an FAA facility has the responsibility for providing aircraft separation at a civilian airport, FAA separation procedures shall be applied to both civilian and military aircraft operating within the FAA facility’s assigned airspace. When a military ATC facility has been delegated the responsibility for providing aircraft separation at a military airport, military separation standards shall be applied to both military and civilian aircraft operating within the military ATC facility’s assigned airspace. When an FAA air traffic control facility is located at and is supporting a military base exclusively, the FAA controllers will apply military separation rules to all the aircraft within the FAA facility’s assigned airspace. When an FAA facility is serving both a military base and a civilian airport, military air traffic control procedures will be applied to DOD aircraft whereas FAA procedures will be applied to all civilian aircraft operating within the FAA facility’s assigned airspace. Military Use of Civilian Airspace The armed forces of the United States periodically conduct training exercises that cannot be accomplished within the confines of restricted and military operation areas. These training exercises, including air intercept and midair refueling training, may require that reduced aircraft separation be applied, which could pose a hazard to civilian aircraft. Procedures have been developed by the DOD and the FAA to permit these exercises to be conducted while still maintaining safe separation between military and nonparticipating civilian aircraft. When such exercises need to be performed, the DOD forwards a request to the FAA to designate and reserve a specific block of airspace where the military authority assumes responsibility for separation of aircraft (MARSA). Air Traffic Control Procedures and Organization / 225 Wherever MARSA airspace has been approved by the FAA, the appropriate military authority assumes total responsibility for the separation of every military aircraft operating within its boundaries. FAA controllers are notified of the MARSA reservation and are responsible for rerouting civilian IFR aircraft around the reserved airspace. VFR aircraft are permitted to operate within MARSA airspace as long as the basic VFR weather conditions exist and can be maintained. While operating within MARSA airspace, the VFR pilot is responsible for seeing and avoiding any participating military aircraft. VFR pilots will be advised of the military operations if they are in contact with an ATC facility. Whenever VFR conditions exist, it is also the military pilot’s responsibility to see and avoid any civilian VFR aircraft operating in MARSA airspace. Air Defense Identification Zones To protect national security, FAR 99 describes procedures to be used whenever aircraft from a foreign country enter the airspace of the United States. FAR 99 defines six zones of airspace surrounding the United States known as air defense identification zones (ADIZs) (see Figure 5–4). These zones are designed to facilitate the early identification and possible interception of any unidentified aircraft inbound to the United States. The six ADIZs are: Atlantic Coastal ADIZ Gulf of Mexico Coastal ADIZ Southern Border Domestic ADIZ Alaskan Distant Early Warning Identification Zone (DEWIZ) Hawaiian Coastal ADIZ Pacific Coastal ADIZ Pilots penetrating an ADIZ are required to comply with the following regulations, or their aircraft may be considered as unidentified and they may find themselves being intercepted by U.S. government aircraft: A flight plan must have been filed with the FAA prior to departing from the foreign country. This can be either an IFR or a defense visual flight rule (DVFR) flight plan. A DVFR flight plan is a modified VFR flight plan designed for air defense use exclusively. DVFR flight plans require pilots to specifically describe the exact location and time when their aircraft will penetrate the ADIZ. Any aircraft penetrating an ADIZ must be equipped with a two-way communications radio operating on approved frequencies. This radio may operate in the HF, VHF, or UHF band. All IFR aircraft must follow normal position-reporting procedures. VFR aircraft must report to the FAA prior to penetrating an ADIZ. (This report must be made 15 to 60 minutes prior to entry, depending on the type of aircraft and its location.) VFR pilots must penetrate the ADIZ at the exact location and time specified in the DVFR flight plan. Any error exceeding about 10 minutes or 20 miles from what is stated on the flight plan will make the aircraft subject to interception by 226 / CHAPTER 5 Figure 5–4. An air defense identification zone as depicted on a sectional chart. U.S. government aircraft. These aircraft may be affiliated with the Department of Defense, U.S. Coast Guard, or U.S. Customs Service. Any pilot who does not observe these procedures will likely be intercepted and ordered to follow the intercepting aircraft to an airfield where a thorough investigation of the pilot, passengers, and aircraft can be conducted. The pilots could be charged with any number of legal violations, including violating the Air Traffic Control Procedures and Organization / 227 provisions of FAR 99. The air intercept procedures used by these aircraft are described in the Aeronautical Information Manual. There is no ADIZ along the borders of the United States and Canada. Because the air defense of the North American continent is maintained jointly by Canadian and American military forces, it is assumed that any unknown aircraft that may have penetrated Canadian national airspace will be intercepted and identified by Canadian military authorities before it reaches the U.S. border. U.S. Customs Service regulations still apply, however, to aircraft flying from Canada to the United States. These regulations include the filing of a flight plan, landing at an international airport, and inspecting the aircraft and passengers by customs agents. In response to the events of September 11, 2001, the FAA established the Washington, D.C. Metropolitan Area Air Defense Identification Zone (DC ADIZ). The purpose of this zone is similar to the previously mentioned ADIZs but it is located entirely in domestic airspace. In general, the DC ADIZ is the airspace located within a 30 nautical mile radius of Washington up to, but not including FL 180. Aircraft desiring to enter this airspace must: • File a flight plan. • Be equipped with a two-way radio and obtain an ATC clearance. • Be equipped with an altitude reporting transponder. • Monitor the emergency frequency of 121.5 mHz, if able. • Squawk the assigned transponder code continuously. • If VFR, operate at an indicated airspeed of 180 knots or less. Typically, the only clearances issued in this airspace permit an aircraft to land or depart at one of the small local airports. The ADIZ regulation expressly prohibits the following operations: • Flight Training • Practice Instrument Approaches • Aerobatic Flight • Glider Operations • Parachute Operations • Ultralight Flights • Hang Gliding • Balloon Operations • Agriculture/Crop Dusting • Banner Towing Operations • Model Aircraft Operations • Model Rocketry • Unmanned Aircraft Systems (UAS) 228 / CHAPTER 5 Foreign Air Traffic Control Services A number of FAA facilities border air traffic control facilities operated by the governments of neighboring countries. These include many of the ATC facilities near the Canadian and Mexican borders. In addition, Alaskan, Hawaiian, Puerto Rican, and Canal Zone facilities may also interact with ATC facilities from other countries. Air route traffic control centers whose jurisdiction includes oceanic flight also interact with foreign ATC facilities. In general, unless otherwise agreed to, U.S. air traffic control’s responsibility ends at the boundary between the two countries. In some areas, particularly along the American Canadian border, operational requirements make it advantageous for the ATC service of one country to control traffic within the sovereign airspace of the other country. In some cases, FAA air traffic control facilities have been given responsibility for the separation of aircraft operating within the other nation’s airspace, whereas in other areas the foreign country may be authorized to control air traffic within U.S. airspace. When control authority has been granted to the United States, basic FAA air traffic control procedures are applied as long as they do not unduly conflict with the procedures used by the other country. In particular, in 1985 the United States and Canada signed an agreement recognizing the essential safety of each country’s air traffic control procedures. The agreement stipulates that each country may use its own ATC procedures even when separating aircraft that are within the other country’s airspace. Since much of the world’s airspace lies over international waters, where no nation has the legal right to control or restrict air traffic, ICAO member nations have agreed to assign aircraft separation responsibility within international airspace to specific countries. These chosen countries are responsible for providing air traffic control services using ICAO-approved procedures. ICAO has assigned most of the Gulf of Mexico and about half of both the Atlantic and the Pacific oceanic airspace to the FAA. Because the FAA does not legally have the right to control flights within these areas, they are known as flight information regions (FIRs). All ICAO member nations have agreed to comply with the procedures used by the FAA when it provides ATC services within these FIRs. Privately Operated ATC Facilities Because the FAA has limited resources for discharging its mission, it is unable to construct and staff an ATC facility at every airport that wants one. The FAA uses a standard formula, based on a number of factors, to determine whether an ATC facility should be constructed or whether an existing facility should remain in operation. These factors include: The number of airline flights at the airport. The number of airline passengers who use the airport. The total number of flights into the airport. The total number of IFR flights into the airport. Any other factor that may warrant the construction of a facility, such as intensive student training, proximity to a larger airport, and so on. Air Traffic Control Procedures and Organization / 229 Immediately after the PATCO strike of 1981, the FAA closed many lowactivity VFR towers which allowed the controllers of those towers to move to larger facilities. In an effort to reopen the towers, the FAA initiated the Federal Contract Tower (FCT) program which offered private contractors a subsidy to operate them. Although operated by private contractors, controllers at these towers must possess the same qualifications, follow the same rules, and meet the same training and proficiency requirements as FAA-operated towers. Additionally, pilots are required to conform to instructions issued by these controllers just as if they were operated by the FAA. There are some situations in which low-activity airports do not qualify for FAA facilities, but the airport operator decides to construct and operate their own air traffic control tower. The local airport operating authority may choose to hire and train its own air traffic controllers or may contract out this responsibility to a private air traffic control company. In either case, the control tower personnel must be certified by the FAA and use the same procedures as FAA controllers. Non-FAA control towers are primarily concerned with separating VFR traffic within the immediate vicinity of the airport and are seldom delegated authority for IFR separation. This responsibility is usually assigned to a nearby FAA or military ATC facility. Delegation of Responsibility As stated previously, the FAA has been given the responsibility of separating every aircraft participating in the nation’s air traffic control system. The definition of participating aircraft is: Any aircraft operating under an FAA clearance in controlled airspace, using IFR flight rules. VFR aircraft operating within areas of designated airspace where air traffic control participation is mandatory (such as Class A, B, C, or D airspace). The FAA has chosen to distribute this separation responsibility domestically to twenty-two air route traffic control centers in the United States (see Figure 5–5a). These ARTCCs are located in the following cities: Albuquerque ARTCC Albuquerque, New Mexico Anchorage ARTCC Anchorage, Alaska Atlanta ARTCC Hampton, Georgia Boston ARTCC Nashua, New Hampshire Chicago ARTCC Aurora, Illinois Cleveland ARTCC Oberlin, Ohio Denver ARTCC Longmont, Colorado Fort Worth ARTCC Euless, Texas 230 / CHAPTER 5 Honolulu ARTCC Honolulu, Hawaii Houston ARTCC Houston, Texas Indianapolis ARTCC Indianapolis, Indiana Jacksonville ARTCC Hilliard, Florida Kansas City ARTCC Olathe, Kansas Los Angeles ARTCC Palmdale, California Memphis ARTCC Memphis, Tennessee Miami ARTCC Miami, Florida Minneapolis ARTCC Farmington, Minnesota New York ARTCC Ronkonkoma, New York Oakland ARTCC Fremont, California Salt Lake City ARTCC Salt Lake City, Utah Seattle ARTCC Auburn, Washington Washington ARTCC Leesburg, Virginia Because an individual controller cannot possibly separate all the aircraft within a particular ARTCC’s boundaries, every center is divided into numerous smaller areas called sectors. Each of these sectors is fashioned in a logical manner, taking into consideration the airway structure and traffic flows. The process of sectorization is designed to make it easier for the controller to separate all aircraft within the sector. Every ARTCC’s airspace is partitioned both vertically and horizontally into twenty to eighty sectors (see Figure 5–5b). The sectors are usually stratified vertically into two or three different levels. The vertical levels are then further partitioned into additional horizontal sectors. The airspace at most centers is usually stratified into at least two levels: a low-altitude group of sectors extending from the Earth’s surface up to 18,000 feet MSL, and a high-altitude group of sectors extending from 18,000 feet MSL (FL 180) to 60,000 feet MSL (FL 600). Busier centers may stratify into three levels, in which the low-altitude sectors extend from the ground to 18,000 feet MSL, the high-altitude sectors from FL 180 to FL 350, and the super-high sectors from FL 360 to FL 600. This vertical stratification coincides with the VOR airway structure. Aircraft operating on low-altitude victor airways are always separated by low-altitude controllers, whereas aircraft operating on high-altitude jet routes are separated by high-altitude controllers. The physical dimensions of each sector within an ARTCC are specified in the facility directives. Facility directives are similar to letters of agreement but apply only to controllers working within a particular facility. Facility directives specify the horizontal and vertical boundaries of each sector and describe the procedures to be used when aircraft cross the boundary between sectors. Hand off Procedures When an aircraft crosses a sector boundary, the responsibility for separating that aircraft passes on to the controller in the new sector. The original Air Traffic Control Procedures and Organization Figure 5-5(a). Air route traffic control center locations and boundaries. Figure 5-5(b). Low-altitude ARTCC sectors. / 231 232 / CHAPTER 5 Figure 5-6(a). High-altitude ARTCC sectors. Figure 5-6(b). TRACON boundaries. Air Traffic Control Procedures and Organization / 233 controller is known as the transferring controller, whereas the next controller is called the receiving controller. This transfer of separation responsibility is known as the transfer of control. Typically, the pilot is directed to contact the receiving controller on a different radio frequency prior to crossing the sector boundary. This is known as the transfer of communication. The process of transferring control and communication of an aircraft from one controller to the next is known as a handoff (see Figure 5–7). Handoffs are necessary when aircraft cross sector boundaries and when an aircraft crosses the boundary between two separate ATC facilities, such as between two centers or between a tower and a center. The FAA handbook specifies that the transfer of communication must occur before the aircraft crosses the sector boundary. This ensures that the receiving controller will be in radio contact with the pilot before the aircraft enters his or her sector. This permits the receiving controller to issue any new control instructions to the pilot before the aircraft crosses the sector boundary. Transfer of control does not occur until the aircraft actually crosses the boundary; thus, the receiving controller does not have separation responsibility or authority to change either the aircraft’s route of flight or altitude until the aircraft crosses the sector boundary. The transferring controller must authorize any changes to the aircraft’s route or altitude while it is still in his or her sector. Any clearance issued by the receiving controller cannot instruct the pilot to alter the aircraft’s flight path or altitude until the aircraft crosses the boundary or unless the transferring controller approves. Aircraft in communication with sector B, under control of sector A Transfer of communications point Sector A Aircraft in communication with sector B, under control of sector B Sector boundary Aircraft in communication with sector A, under control of sector A Transfer of control point Sector B Figure 5–7. Example of transfer of communications and transfer of control. 234 / CHAPTER 5 Preferential Routes The FAA has developed a system of preferential routes and altitudes for flight between sectors. Some of these routes are published in the Airport Facility Directory, whereas others are described in facility directives. The consistent use of preferential routes and altitudes enhances traffic flows, thereby reducing the controller’s workload. When more than one airway extends from one busy airport to another, it is common practice to designate each as a one-way airway. This procedure reduces the chance of a head-on collision at or near a sector boundary. If there are insufficient airways to designate one-way airways between facilities, specific altitudes will usually be reserved for inbound aircraft, and other available altitudes will be used by outbound aircraft. In most cases, odd-numbered altitudes such as 3,000, 5,000, 7,000, and so on are assigned to aircraft generally heading east, and even-numbered altitudes are assigned to aircraft heading west. The letter of agreement between the two facilities is specific about the procedures, altitudes, and airways to be used as aircraft cross the facility boundaries. Facility directives are just as specific, defining the routes and altitudes that should be used by aircraft crossing sector boundaries within the facility (see Figure 5–8). Approval Requests and Coordination In some circumstances the controller may need to hand off an aircraft at a different altitude or on a different airway than specified in the letter of agreement. The circumstances may be bad weather, local traffic conditions, or the pilot’s request for a different route or altitude. In these cases, when the procedures specified in the letter of agreement cannot be complied with, the two controllers involved must effect coordination before the aircraft crosses the boundary. In the coordination process, one controller asks for and receives permission from the other controller to deviate from the terms of the letter of agreement. When effecting coordination, the transferring controller contacts the receiving controller and requests approval for a route or altitude not specified in the letter of agreement or facility directive. This type of request is known as an approval request (APPREQ). If the receiving controller determines that the approval request can be accommodated without denigrating safety or delaying other traffic, approval will normally be granted. Approval of an APPREQ is always left to the discretion of the receiving controller, since he or she will ultimately be responsible for the separation of the aircraft once it enters his or her sector. Approval requests are used whenever a controller wants to use a procedure that conflicts with those contained in letters of agreement or facility directives. A controller can never be granted approval to deviate from the procedures contained in the FAA handbook, however. Application of the procedures included in the handbook is mandatory for controllers. A typical approval request would be accomplished as follows: TRANSFERRING CONTROLLER: APPREQ Rummy five niner at 7,000 over Pines. RECEIVING CONTROLLER: Rummy five niner at Pines at 7,000 approved. Air Traffic Control Procedures and Organization Departure Airport Preferred Route 235 Destination Airport ATL ATL V97 NELLO V311 HCH V51 CGT V7 BEBEE ORD ORD ATL ATL EAONE AHN J208 HPW J191 PXT KORRY-STAR LGA LGA ATL ATL WETWO VUZ J41 MEM RZC PER GCK J154 RYLIE DANDDSTAR DEN DEN BOS BOS MHT CAM J547 SYR J547 BUF J94 ECK J38 GRB J106 GEP J70 ABR J32 MLD J158 MVA MODESTO-STAR SFO SFO BOS BOS LUCOS SEY067 SEY HTO J174 ORF J121 CHS J79 OMN ANNEY-STAR MIA MIA BOS BOS BOSOX V419 V14 ORW V16 DPK JFK JFK BWI BWI V93 PXT V213 COLIN HCM J193 J121 CHS J79 OMN ANNEYSTAR MIA MIA CHI CHI EON DNV VHP299 VHP J24 HVQ BKW ROA SOUTH_BOSTONSTAR RDU RDU CHI CHI PLL PLL275/065 FOD J94 ONL J114 SNY LANDR-STAR DEN DEN CVG CVG HYK VXV J99 IRQ J85 GNV GULLO_RNAV-STAR PBI PBI CVG CVG HYK VXV J99 IRQ J85 AMG LEESE-STAR ORL ORL DCA DCA BUFFR J518 DJB J34 BAE EAU_CLAIRE-STAR MSP MSP DCA DCA PALEO V312 GOLDA V268 ENO V16 JFK V229 HFD V3 WOONS BOS BOS DEN DEN ICT RZC VUZ MGM SZW J41 CYPRESS-STAR MIA MIA DFW DFW SQS J52 ATL AHN J208 HPW J191 PXT KORRY-STAR LGA LGA DTW DTW WINGS V103 ACO ACO145 J518 J152 JST BUNTS-STAR PHL PHL DTW DTW ANNTS DXO217 FWA071 FWA MIE V14 CLANG-STAR IND IND EWR EWR COATE J36 ULW141 ULW V36 YYZ YYZ EWR EWR WHITE J209 SBY J79 KATZN J193 J121 CHS J79 OMN BITHOSTAR MCO MCO HOU HOU BTR SJI J37 MGM MGM048/138 GRD J209 RDU J207 FKN J79 JFK NORWICH-STAR BOS BOS HPN HPN WHITE J209 SBY J79 KATZN J193 J121 CHS J79 OMN BITHOSTAR MCO MCO IAD IAD DAILY J61 HUBBS KEMPR WETRO DIW AR19 AYBID MIMMI NEUBE SWOMP SANZZ CASKI PBI PBI IND IND V275 KLINE VWV VWV051 POOFE DET DET JFK JFK GAYEL J95 BUF J16 ECK J38 GRB J106 GEP J70 ABR J32 FMG ILA PYE SFO SFO JFK JFK RBV J230 AIR J80 EMPTY DQN CLANG-STAR IND IND LAS LAS BCE MTU OCS J94 ONL J94 DBQ JVL JANESVILLE-STAR ORD ORD Figure 5–8. Preferred routes. (continues) / 236 / CHAPTER 5 Departure Airport Preferred Route Destination Airport LAX LAX SEAL_BEACH-DP SLI SLI148 V25 V165 SARGS SAN SAN LAX LAX DAG J100 OBK J584 CRL J554 JHW J70 LVZ LENDY-STAR JFK JFK LGA LGA ELIOT J80 AIR J110 STL J19 ZUN FOSSL-STAR PHX PHX MCO MCO MCCOY-DP SAV J55 CHS J121 SWL SWL034 RADDS CEDAR_ LAKE-STAR PHL PHL MKC MKC LAKES-DP COU STL J24 VHP J80 J30 BUCKO BUCKO-STAR DCA DCA MSP MSP ODI J30 BRIBE BDF ENL ENL162 PLESS J45 ATL J89 OTK LEESE-STAR ORL ORL ORD ORD MUSKY V100 ELX V218 LAN SPRTN-STAR DET DET PHL PHL PTW PTW320 V499 V164 FQM V31 ULW V36 YYZ YYZ PHX PHX GUP J102 ALS PUB GLD J146 GIJ J554 JHW J70 LVZ LENDYSTAR JFK JFK PIT PIT EWC EWC050 J584 SLT J190 ALB GDM GARDNER-STAR BOS BOS RDU RDU PACKK-DP AZELL HVQ J24 VHP OKK KOKOMO-STAR ORD ORD SAN SAN DVC J197 GLD J192 IOW J146 J34 DJB V30 ACO V337 CUTTA PIT PIT STL STL J110 GCK J154 RYLIE DANDD-STAR DEN DEN In this example, the transferring controller has requested that Air Force Rummy five niner be permitted to enter the receiving controller’s airspace at the Pines intersection at an altitude of 7,000 feet. This is apparently either the wrong altitude or a route of flight different from that specified in the letter of agreement between the two facilities. The receiving controller has determined that safety will not be compromised if Air Force Rummy five niner enters the sector at this route and altitude and has granted approval. The transferring controller must then advise the pilot to contact the receiving controller before the aircraft crosses the sector boundary. The basic rule of air traffic control separation is that every controller is responsible for the separation of participating aircraft for the duration of time the aircraft is within the controller’s sector of responsibility. Controllers are never permitted to change the route or altitude of an aircraft while it is in another controller’s area without the express permission of that controller. Conversely, a controller must always transfer both control and communication before an aircraft crosses the boundary into the receiving controller’s airspace, unless approval has been granted by the receiving controller. Air Traffic Control Procedures and Organization / 237 Controller Duties in an Air Route Traffic Control Center Flight Data Controllers Every sector within an ARTCC usually has one to three controllers assigned to separate the aircraft within that sector. The first position that most controllers in an ARTCC are assigned to is the role of flight data controller. The flight data controller is responsible for assisting the other controllers, who actually separate the aircraft. The flight data controller effects coordination with other controllers and passes along pertinent flight information to controllers working in other sectors. Radar Controllers Every ARTCC sector equipped with radar is staffed by a controller whose responsibility is to separate participating aircraft using a radar-derived display. Radar controllers issue altitude, heading, or airspeed changes to keep the aircraft separated and in compliance with the various letters of agreement and facility directives that may apply to that sector. Radar Associate/ Nonradar Controller Every sector within the center is also staffed by a radar associate/nonradar controller whose duties are to assist the radar controller when separating aircraft that do not appear on the radar display. The nonradar controller’s duties include updating the flight progress strips to accurately reflect every aircraft’s position, altitude, and route of flight. The nonradar controller uses this information to separate aircraft that are either too low or too far away to be displayed on the radar. The nonradar controller must be prepared to assume aircraft separation responsibility if the radar display should malfunction. The nonradar controller’s duties are similar to those performed by the B controller in the old air traffic control centers. Air Traffic Control Tower Responsibilities When it is operationally advantageous for an ARTCC to delegate separation responsibility to an air traffic control tower (ATCT), an appropriate letter of agreement is drafted by representatives of both the tower and the center. This letter of agreement delineates the control tower’s area of responsibility and formally transfers the responsibility for aircraft separation to the tower. In most cases, the control tower is delegated the responsibility for separation of participating aircraft operating within about a 40-mile radius of the airport. This airspace usually extends from the Earth’s surface up to an altitude of 6,000 to 10,000 feet MSL. The letter of agreement between the tower and the center also specifies how and where the transfer of control and communication will occur. If the tower’s delegated airspace is adjacent to that of another tower or a different 238 / CHAPTER 5 center, a letter of agreement is also drafted by representatives from each of these facilities, describing the procedures to be used when handing off aircraft as they cross the facility boundaries. Since the control tower’s designated airspace is usually too large or complex for one controller to safely handle, it is usually divided into smaller sectors, with individual controllers responsible for aircraft separation within each sector. The facility manager, after consulting with the controllers, drafts and distributes a facility directive that defines the operating rules and procedures controllers should use when separating aircraft within the control tower’s delegated airspace. Most control towers have at least three and as many as ten operating positions where controllers might work. Every position has standardized duties and functions, which are described in the remainder of this chapter. Keep in mind, however, that each air traffic facility has its own unique requirements that might modify the generic job responsibilities described here. Ground Control The ground controller works in the glass-enclosed portion of the tower known as the tower cab and is responsible for the separation of aircraft and vehicles operating on the ramp, taxiways, and any inactive runways. This responsibility includes aircraft taxiing out for takeoff, aircraft taxiing into the terminal building after landing, and any ground vehicles operating on airport movement areas. Airport movement areas do not include those areas solely reserved for vehicular traffic such as service roads or boarding areas. The ground controller is assigned a unique radio frequency to communicate with pilots and vehicle operators. The most common ground control frequency is 121.90 mHz. In congested areas where two or more control towers are located near each other, ground controller transmissions from each airport might overlap, causing pilot misinterpretation. Thus, in such cases each control tower is assigned a different frequency for its ground controllers. These additional frequencies are usually 121.80 or 121.70 mHz. The duties of the ground controller include: Providing instructions to taxiing aircraft and ground support vehicles. Controlling taxiway lighting systems. Issuing clearances to IFR and participating VFR aircraft. Coordinating with the local controller when taxiing aircraft need to operate on active runways. Issuing weather and NOTAM information to taxiing aircraft. Receiving and relaying IFR departure clearances. Relaying runway and taxiway condition information to airport management. At less busy air traffic control towers, the ground controller may also be responsible for coordinating with other facilities and issuing ATC clearances to aircraft prior to departure. At busier control towers, these tasks are assigned to a clearance delivery controller, who is assigned a frequency separate from that Air Traffic Control Procedures and Organization / 239 used by the ground controller. At very busy locations, a flight data controller may also be on duty to assist the ground controller when coordinating with other controllers. Local Control The local controller is primarily responsible for the separation of aircraft operating within the airport traffic area and those landing on any of the active runways. The local controller is assigned a unique radio frequency that permits communication with these aircraft. The primary responsibility of the local controller is arranging inbound aircraft into a smooth and orderly flow of traffic and sequencing departing aircraft into this flow. The local controller’s responsibilities are complicated by the fact that most of the airports in this country do not have sufficient nonintersecting runways to handle the number of aircraft that want to land or take off. Thus, the local controller may be forced to use two or three runways that intersect each other. At very busy facilities, the local controller’s workload may be too much for one person to handle. In such cases, the local control position is split into two, with each controller responsible for different runways and assigned separate radio frequencies. Duties performed by the local controller include: Determining the active runway. Issuing landing and takeoff clearances. Issuing landing information. Sequencing landing aircraft. Coordinating with other controllers. Issuing weather and NOTAM information to pilots. Operating the runway and approach light systems. Approach and Departure Control At busy facilities that have been delegated a large amount of airspace from the ARTCC, an approach and departure control position is usually designated. This position is commonly referred to simply as the approach control position. At smaller, less busy towers, approach control may be the responsibility of one controller stationed in the tower cab itself, but at larger and busier airports equipped with radar, the approach control may be housed in a separate building located near the tower. This facility is known throughout the FAA as a terminal radar approach control (TRACON). The TRACON may be equipped with up to twenty radar displays and may be staffed by up to forty controllers at a time. At most facilities, TRACON controllers may also occasionally work in the tower cab, but at some of the larger TRACONs they are assigned strictly to the approach control facility. The airspace controlled by a TRACON is usually too large to be administered by one controller and is divided into smaller, more manageable sectors. The physical dimensions of each sector and the procedures controllers use as aircraft pass from one sector to another are delineated in the appropriate facility directives.