Chapter 10: Nolan - PDF

418 / CHAPTER 10 A detailed description of flight through the air traffic control system is too complex to be completed in an entire textbook, much less a single chapter. Thus, this chapter attempts to summarize the process by presenting examples of how simple IFR and VFR flights are conducted in th...

418 / CHAPTER 10 A detailed description of flight through the air traffic control system is too complex to be completed in an entire textbook, much less a single chapter. Thus, this chapter attempts to summarize the process by presenting examples of how simple IFR and VFR flights are conducted in the air traffic control system, using two simulated flights. The first is a simulated IFR airline flight from Phoenix, Arizona, to Indianapolis, Indiana. The second example simulates a VFR flight from Lafayette, Indiana, to Champaign, Illinois. After following these simulated flights, you should have a good idea of how the ATC system actually works. Overview of an IFR Flight Flight Planning and IFR Clearances Pilots of personal and corporate aircraft usually contact a flight service station (FSS) to file a flight plan and receive weather briefings. An increasing number of pilots, however, are using private weather-briefing firms and are able to file flight plans directly through these organizations. Airlines usually file flight plans for their pilots and military pilots through their military operations office. Prior to beginning a flight, the pilot receives a thorough weather briefing that includes both current and forecast weather conditions along the route of flight. These conditions include known or suspected ATC delays, navigation equipment outages, and any notices to airmen (NOTAMs). NOTAMs are entered into the FAA computer system by local flight service stations or at the Flight Data Center (FDC) in Washington, D.C. NOTAMs issued by local flight service stations include local conditions such as airport or runway closures and unlit obstructions. NOTAMs issued by the Flight Data Center, known as FDC NOTAMs, concern en route navaid outages, changes to published instrument approach procedures, or any emergencies (see Figure 10–1). Once the weather briefing is completed, and the flight plan information has been entered into the computer, the information is digitally transmitted to Atlanta ARTCC (ZTL) where it is checked for accuracy and for proper routing. ZTL ARTCC is the primary flight data processing center. Salt Lake City ARTCC (ZLC) is the backup flight data processing facility. Beginning in 2008, the FAA implemented changes in all computer systems that permit the automatic assignment of RNAV routes, based on installed aircraft equipment and capabilities. Pilots filing flight plans that use RNAV departures and arrivals must now use the ICAO flight plan format when filing flight plans. Coded Departure Routes The FAA publishes about 15,000 different routes in a standard format that is identified using a unique code for each route. These routes are known as coded departure routes (CDR). Pilots familiar with CDR requirements and with access to the database can place the phrase “CDR-capable” in their flight plan, advising the FAA that the aircraft has the required navigation equipment and enough fuel to fly the CDRs. An example of CDRs from Phoenix to Indianapolis are included in Figure 10–2. Operation in the National Airspace System / 419 Dallas-Love Field FDC 7/1246 /DAL/FI/T DALLAS-LOVE FIELD, DALLAS, TX. RADAR-1 AMDT 24, S-13L MDA 1000 HAT 515 ALL CATS. VIS CAT C 5000, CAT D 6000. S-13R MDA 1000 HAT 524 ALL CATS. VIS CAT C 1 1/2, CAT D 1 3/4 FDC 7/1066 /DAL/FI/T DALLAS-LOVE FIELD, DALLAS, TX. ILS RWY 31R ORIG. CIRCLING VIS CAT B 1 1/4, CAT C 2 1/2, CAT D 2 3/4 FDC 7/1035 /DAL/FI/T DALLAS-LOVE FIELD, DALLAS, TX. ILS RWY 31L AMDT 15. S-I DME MINIMA MDA 1360 HAT 885 ALL CATS. VIS CATS A/B RVR 4000, CAT 2 1/4, CAT D 2 1/2. CIRCLING MDA 1400 HAA 913 ALL CATS. VIS CATS A/B 1 1/4, CAT C 2 3/4, CAT D 3. DME MINIMA: S-LOC 31R MDA 1340 HAA 853 ALL CATS. VIS CAT A 1/2, CAT B 3/4, CAT C 2, CAT D 2 1/4 FDC 7/811 /DAL/FI/T DALLAS-LOVE FIELD, DALLAS, TX. IFR TAKEOFF MINIMUMS RWYS 31L/R AND RWY 36 STANDARD. RWYS 13L/R AND RWY 18 1000-2 OR STANDARD WITH A MIN CLIMB OF 290 FT PER NM TO 1500. FDC 6/1813 /DAL/FI/T DALLAS-LOVE FIELD, DALLAS, TX. ILS 31L AMDT 15, S-ILS 31L NA. S-LOC 31L. MDA 1600, HAT 1125 ALL CATS, CIRCLING 1600 HAA 1113 ALL CATS. ENTRA DME FIX RELOCATED LUE 4.1 DME. REASON: 889 AGL. 1339 AMSL CRANE 3.9 NM SE OF AIRPORT Figure 10–1. A sample FDC NOTAM. CDR Code Route of Flight (1,298 nm if directly flown) CDR Miles Percent Extra PHXINDCM J65 CME TXO J74 IRW J78 FAM ENL BIB KELLY 1,361 nm 5% PHXINDLW SILOW1 RSK ALS J102 SLN J24 MCI J80 1,322 nm 2% PHXINDMA MAXXO1 CNX J74 IRW J78 FAM ENL BIB KELLY 1,338 nm 3% PHXINDSJ SJN3 ABQ J18 SLN J24 MCI J80 1,306 nm 1% Figure 10–2. Partial list of coded departure routes from Phoenix to Indianapolis. The FAA also maintains an internal list of certain preferred routes between city pairs and within certain blocks of airspace. These are the routes that controllers must issue to aircraft, regardless of the pilots’ filed route of flight. These can dynamically change based upon seasonal, daily, or even hourly projected traffic flows. Most airlines are familiar enough with standard routings that they routinely file the FAA preferred routes. If the pilots do not, the flight data computer at Atlanta ARTCC will amend the flight plan, substituting the preferred route of flight in place of that filed by the pilot. In the example flight that will be used in this chapter, the pilot might have filed a route from the Phoenix airport, direct to the Albuquerque VORTAC, direct to the Wichita VORTAC, direct to the St. Louis VORTAC, then direct to the Indianapolis airport. This would be indicated on the flight strip as PHX..ICT..STL..IND 420 / CHAPTER 10 But the flight data processing computer at Atlanta center would substitute a preferred route, if one existed. For example, the new clearance might become PHX.SJN3.ABQ.J18.FTI.J19.STL..BIB.RACYR1.IND This would be translated as Phoenix airport to the Albuquerque VORTAC via the San Juan 3 departure, then J18 to the Fort Union VORTAC, J19 to the St. Louis VORTAC, direct to the Bible Grove VORTAC, then via the Racyr One standard terminal arrival route to the Indianapolis airport. Traffic Flow Management Programs The Air Traffic Control System Command Center (ATCSCC) located outside of Washington would also receive the flight plan information. The ATCSCC is responsible for ensuring that the arrival airport will be able to handle flights when they are scheduled to arrive. Problems that could occur at the arrival airport might include capacity restrictions due to overscheduling, low visibility, runway closures, or convective weather. Every major airport in the United States has determined the number of aircraft that can be safely landed in any given hour based upon weather conditions and runway configurations. This is known as the airport acceptance rate (AAR) and is published by the FAA. The Indianapolis International Airport has two independent, parallel runways and can typically handle between twelve and fifty-two aircraft per hour (see Figure 10–3). These limits have been established by experts familiar with the airport layout and traffic flows. For example, the lowest limit of twelve arrivals per hour at Indianapolis occurs if only a single runway is available during low IFR weather conditions. If two runways are available and the weather is VFR, Indianapolis can handle up to fifty-two arrivals per hour. If the ATCSCC determines that too many aircraft are scheduled to arrive at an airport during any given time period, a ground delay will be issued to some aircraft. Ground delays transfer any expected flight delay to the aircraft Figure 10–3. Indianapolis airport runway capacities. Operation in the National Airspace System / 421 while still on the ground prior to departure. Ground delays are a safer and more fuel-efficient way for aircraft to absorb known delays. For example, if an airport could only accept sixty aircraft in any given hour (hour #1), but eighty were scheduled to arrive during that hour, twenty aircraft would have to be delayed. The last twenty aircraft scheduled to arrive during hour #1 that weren’t yet airborne would be issued sufficient departure delay to ensure that they would arrive at the beginning of hour #2. If more than sixty total aircraft were now scheduled to arrive during hour #2, a sufficient number of them would be issued a departure delay to ensure that they arrived in hour #3. This process of delay would continue until all the flights arrive. The FAA, airlines, pilots, and others can easily determine if an airport is predicted to have any overloads during any given time period. Using FAA collaborative decision products, a user can look at the airport demand graphic for any arrival airport to determine if an excessive number of flights are scheduled to arrive during any given 60-, 30-, or 15-minute time period and whether a delay is likely (see Figure 10–4). Figure 10–4. Newark Airport demand chart. 422 / CHAPTER 10 Another tool that can be used by operators is the FAA’s advisory database system. Every 3 hours the FAA confers with major system users, makes collaborative decisions, and then disseminates that information to users via a plan of operations. The plan advises operators of possible delays and other system problems (see Figure 10–5). Operators can than adjust their schedules ahead of time if needed. Sometimes simple solutions can be applied that solve the delay problem. For example, if there are numerous delays into a major airport, an airline might Figure 10–5. Plan of operations. Operation in the National Airspace System / 423 choose to combine two partially full flights into one full flight, thereby reducing expenses and the number of aircraft attempting to fly into a congested airport. Other operators may choose to use alternate airports or simply cancel flights. In any case, the FAA makes the plan known well in advance for system users. After any airline or other operator adjustments are made, if the demand for an airport is still predicted to exceed its capacity, the ATCSCC will issue an advisory and start calculating and disseminating individual aircraft ground delays. Once an aircraft’s ground delay is calculated, it is added to the pilot’s proposed departure time and is called an expect departure clearance time (EDCT). For example, if a pilot filed a flight plan to depart the Phoenix airport at 1445Z, with a planned arrival in Indianapolis at 1800Z, but the ATCSCC calculated that the aircraft’s arrival needed to be delayed till 1850Z, a 50 minute delay would be added to the proposed departure time, giving an EDCT from Phoenix of 1535Z. If an EDCT is issued, it is printed directly on the flight progress strip at the PHX tower for issuance to the pilot. Another method of obtaining the EDCT is for a controller at the tower to call the ATCSCC directly. At most busy airports, if there are expected system delays, a traffic management controller will be assigned this duty (see Figure 10–6). Figure 10–6. Ground delay advisory for Newark Airport. 424 / CHAPTER 10 Alternative Routes The ATCSCC also checks to make sure that there are no flow constrained areas (FCA) along the route of flight. An FCA is a block of airspace that has some actual or forecast temporary flight restriction that might reduce its capacity. Severe weather avoidance plans (SWAP) or alternate playbook routes might be issued if, in the opinion of the ATCSCC, overall efficiency will be improved by rerouting the aircraft. SWAP may be invoked when a large-area, long-duration weather event threatens to disrupt a large section of airspace. Typical scenarios include large convective systems that routinely occur over the middle and southern portions of the United States during the spring and summer. If the ATCSCC deems it necessary, various SWAP options can be selected that route aircraft around the projected areas that will be impacted by the weather. These alternative routes will be issued prior to departure so that aircraft operators and planners can adjust their operations as necessary. Playbook routes are a set of published alternative routes to an airport or through potentially heavily congested airspace that are invoked when traffic flow is predicted to be affected (see Figure 10–7). Playbook routes are used when both the receiving facility (usually a TRACON) and the ATCSCC determine that for a period of time, traffic along a busy route will be affected by weather. Playbook routes typically offer alternatives for the pilots that either trail behind the weather as it clears the area or provide an alternative path in front of the weather. The difficulty with invoking SWAP or issuing playbook routes is that most of the route changes affect the entire route of the aircraft, from departure airport to destination. The idea is that it is easier to plan and it might actually shorten the overall extension to the flight if a route adjustment can be made early in the flight. This keeps the system from having to divert large numbers of aircraft in a chaotic manner at the edge of a flow constrained area. The difficulty is in predicting the overall movement of the weather area and determining whether it will even occur. To properly issue alternative routes, someone must decide hours before the weather event when it will happen, the extent of its effect on the airspace, how far it will move, and how fast. All of these predictions are currently impossible to forecast with tremendous accuracy, so there are times when the ATCSCC invokes actions for weather that never occurs or sometimes does not invoke alternative plans when weather is stronger than anticipated. This ability to predict and adjust traffic flows is still more of an art than a science. Clearance Delivery One of the duties of the clearance delivery controller (see Figure 10–8) is usually to create and keep the ATIS recording updated. For the purpose of this flight, we will assume that “information kilo” is the current ATIS at PhoenixSky Harbor Airport. At many larger airports, digital or d-ATIS is available to pilots and other operators. Digital ATIS is a digitally transmitted version of the ATIS audio broadcast and can be accessed on the flight deck and in flight operations in real time. An example of an ATIS recording at Phoenix follows. Operation in the National Airspace System / 425 Figure 10–7. Playbook route into Chicago O’Hare International Airport. Phoenix-Sky Harbor Airport information kilo, two two one five zulu weather. Wind two five zero at one four, gust two zero, visibility one zero. Few clouds at one one thousand, two five thousand scattered. Temperature two five, dew point minus three, altimeter two niner eight one. Runways seven right, seven left and eight in use. Simultaneous approaches in use. Expect visual approach runway eight or runway seven right. I-L-S runways eight and seven right approaches in use. Departing runway seven left. Low level wind shear advisories are in effect. All pilots should read back hold short instructions. All aircraft taxi with transponder on. Advise you have information kilo. 426 / CHAPTER 10 Phoenix Air Traffic Control Tower Operating Positions, Duties, and Responsibilities (excerpted) PURPOSE: This document specifies standard operating procedure at the Phoenix Sky Harbor Air Traffic Control Tower and TRACON CANCELLATION: Phoenix Tower SOP dated August 3, 1981. SCOPE: The procedures herein are for the purpose of conducting operations at the Phoenix Air Traffic Control Tower and TRACON within the airspace delegated to each position. PROCEDURES: General Deviations from procedures contained in this letter of agreement are authorized on an individual aircraft basis after coordination between involved controllers. Aircraft Group Definitions Group A: Turbojets Group B: Turboprops Group C: All other aircraft and helicopters Traffic Flow Definitions East Flow: Runways 7R/7L/8 in use. West Flow: Runways 25L/25R/26 in use. Runways 7L/25R is the primary departure runway Runways 7R/8 and 25L/26 are primarily arrival runways Air Traffic Control Tower Operating Positions Clearance Delivery - 118.10 Ground South - 132.55 Ground North - 119.75 Local South - 120.90 Local North - 118.70 CLEARANCE DELIVERY Records ATIS Reviews flight strips for accuracy and makes valid, timely amendments as necessary. Issues IFR clearances. Coordinates EDCTs with ATCSCC and the TMUs at P50 and ZAB Assign all aircraft the following initial altitude restriction. Advise that they can expect their filed altitude 10 minutes after departure. IFR Group A aircraft – 7,000⬘ MSL IFR Group B/C aircraft – 4,000⬘ MSL VFR aircraft – at or below 4,000⬘ MSL. North departures will be issued a departure control frequency of 119.2 South departures will be issued a departure control frequency of 126.8 GROUND CONTROL Aircraft shall be assigned a departure runway as follows unless another runway is specifically requested by the pilot and coordination with the Local Control position(s) is accomplished. Opposite direction operations are prohibited. Figure 10–8. Phoenix Tower standard operating procedures. Operation in the National Airspace System / 427 Aircraft north of Runway 8/26, assign Runway 8 or 26 for the flow in use. Aircraft south of Runway 7R/25L, assign Runway 7R or 25L for the flow in use. All group A aircraft should, to the extent possible, be assigned runway 7L/25R with departures sequenced by alternating northbound and southbound aircraft if practicable. Group B and C aircraft should be assigned runway 8/26 if northbound and runway 7L/25R if southbound. During East Flow Operations Ground North is responsible for the North complex and taxiway “S” south to taxiway “D”. Ground South is responsible for the South complex and taxiways “R” and “T” north to taxiway “C”. During West Flow Operations Ground North is responsible for the North complex and taxiway “S” and “R” south to taxiway “D”. Ground South is responsible for the South complex and taxiway “T” north to taxiway “C”. LOCAL CONTROL Taxi Into Position and Hold (TIPH) operations are authorized in accordance with FAA Order 7110.65, provided: Taxi into position and hold operations shall not be used when an arriving aircraft is within 3 NM of the arrival runway. Taxi into position and hold operations will be suspended during times of poor radio communications, frequency congestion, or pilot inexperience, resuming TIPH when appropriate. Local Control shall provide separation services to all aircraft within tower airspace as defined as the ground up to and including 3,000⬘ MSL. Local South is responsible for aircraft using runways 7R/7L/25R/25L and Taxiway F. Local North is responsible for aircraft using runway 8/26. The transfer of communications to departure control shall normally be accomplished within one mile of the departure end of the runway. Local Control shall notify the appropriate departure controller via automated message systems when departures begin their takeoff roll. Local control shall issue the following departure headings: Group A aircraft – runway heading Group B/C aircraft Northbound during West Flow operations – 290 degrees. Northbound during East Flow operations – 040 degrees. Southbound during West Flow operations – 230 degrees. Southbound during East Flow operations – 110 degrees. VFR aircraft Northbound during West Flow operations – 330 degrees. Northbound during East Flow operations – 010 degrees. Southbound during West Flow operations – 190 degrees. Southbound during East Flow operations – 140 degrees. Figure 10–8. (continued) 428 / CHAPTER 10 Thirty minutes prior to the aircraft’s proposed departure time, the FDP computer at Atlanta center causes a flight strip to be printed at the departure airport. If the departure airport is not served by an ATC facility, or if the facility is not properly equipped, the strip will be printed at the nearest facility. At this time, the FDP computer also assigns the aircraft a transponder code. Since the number of codes available is limited, this procedure is used to effectively ration transponder codes. Assuming that the aircraft is departing from a properly equipped airport, the flight strip will be printed at the clearance delivery position in the control tower. The clearance delivery controller is responsible for ensuring that the aircraft’s altitude and route of flight conform to the appropriate procedures. The controller can then issue the clearance to the pilot. In most cases, procedures specify that the aircraft be initially restricted to an altitude lower than that filed by the pilot. If the controlling facility has responsibility for the airspace extending up to 10,000 feet, for example, the clearance delivery controller must initially restrict the aircraft to this altitude, so that in case of temporary radio failure the aircraft does not leave the vertical confines of the facility’s airspace before a handoff has been accomplished. At some facilities, additional constraints have been imposed on departing aircraft. It is not unusual to restrict an aircraft to an initial altitude of 3,000 to 6,000 feet. The advantages of this procedure will be explained shortly. The clearance delivery controller must issue the pilot the clearance using one of two methods. If no changes were made to the pilot’s requested route of flight, the controller can clear the pilot “as filed.” This means the route that the pilot filed originally is the same route as that contained in the clearance. An “as filed” clearance does not include the pilot’s requested altitude. That altitude must always be stated by the controller when issuing a clearance to the pilot. The phraseology for an “as filed” clearance is Cessna two five two mike november, cleared to Indianapolis International Airport as filed, climb and maintain one zero thousand, squawk three seven four one. If the control tower is equipped with a departure control position, the clearance must also include the departure controller’s frequency. In addition, if facility procedures specify that every departing aircraft should be temporarily restricted to a lower altitude, this restriction must be included as part of the original clearance. If a lower altitude is temporarily assigned, the pilot must be advised as to when the altitude filed in the flight plan might be expected: Cessna two five two mike november, cleared to Indianapolis International Airport as filed, climb and maintain five thousand, expect one two thousand one zero minutes after departure, departure control frequency one two three point seven five, squawk three seven four one. If the aircraft is departing from an airport not served by a facility equipped with radar, the clearance must also include the first airway segment that the Operation in the National Airspace System / 429 pilot has filed. This serves as a double check to ensure that the issued clearance is the same as that originally filed by the pilot: Cessna two five two mike november, cleared to Indianapolis International Airport as filed via victor ninety-seven, climb and maintain five thousand, expect one two thousand one zero minutes after departure, departure control frequency one two three point seven five, squawk three seven four one. If a very small change has been made to the pilot’s route of flight (such as the imposition of a preferred route), the phrase “rest of route unchanged” may still be used, but the changed portion of the route must be stated: Cessna two five two mike november, cleared to the Indianapolis International Airport via victor ninety-two south, Jetts intersection, rest of route unchanged, climb and maintain five thousand, expect one two thousand one zero minutes after departure, departure control frequency one two three point seven five, squawk three seven four one. But if the route has been changed substantially, or if the abbreviation FRC, which stands for full route clearance, is printed on the strip (signifying that the flight service specialist amended the clearance), the entire route of flight must be stated: Cessna two five two mike november, cleared to Indianapolis International Airport via victor three ninety-nine, climb and maintain five thousand, expect one two thousand one zero minutes after departure, departure control frequency one two three point seven five, squawk three seven four one. At terminal facilities not equipped with radar, after the pilot has verified the clearance, the clearance delivery controller enters the estimated departure time of the aircraft into the computer system and passes the strip to the ground controller. At facilities equipped with radar, the radar system will automatically send a departure message to the ARTCC upon receipt of the aircraft’s transponder signal. Phoenix Airspace Within the Phoenix approach control (P50) airspace, in general, departing aircraft are typically climbed to an altitude of 7,000⬘ feet MSL while departing on runway heading. All arrivals are descended to an altitude no lower than 8,000 feet until past the airport while on either a left or right downwind. Once past the airport, they are typically issued a descent to the minimum vectoring altitude (see Figure 10–9). When pilots at Phoenix contact clearance delivery for their clearance, they will initially be restricted to an altitude of 7,000 feet or less to ensure positive vertical separation between departures and arrivals. They must also be issued a time they can expect a higher altitude and a departure control frequency. The clearance then issued by clearance delivery would be 430 / CHAPTER 10 Figure 10–9. Phoenix TRACON minimum Vectoring Altitude chart. Southwest eighteen ninety-four, cleared to the Indianapolis airport via the San Juan 3 departure Albuquerque transition, J18 Fort Union, J19 St. Louis, direct Bible Grove, Racyr One arrival. Climb and maintain seven thousand, expect flight level three five zero, one zero minutes after departure, departure control one one niner point two, squawk five three six two. Operation in the National Airspace System / 431 If the route of flight on the flight progress strip was exactly what the pilot had originally filed, the route section of the clearance could have been replaced with the phrase “cleared as filed,” although the rest of the information would still be read. If the aircraft has automation capabilities, the clearance could be transmitted electronically and printed in the cockpit eliminating the need for the clearance to be read over the air in its entirety. If an EDCT time has been issued, the pilot would be advised by the clearance delivery controller when they could expect to taxi ensuring that they actually take off at or near the EDCT time. When it is time to taxi, the aircraft would be advised to contact ground control, who would issue taxi clearance to the appropriate runway, which according to the ATIS is runway 7L. Ground Control Coded Departure Routes The ground controller is responsible for issuing a taxi clearance that will take the aircraft to the departure end of the appropriate runway (see Figure 10–10). The ground controller is also responsible for any vehicles that must travel on the airport movement area. Taxi instructions are usually issued using a combination of some of the following clearances: Taxi runway seven left. Taxi runway eight via taxiway bravo. Taxi runway seven right, follow the seven twenty-seven off your left. Taxi runway eight, pass behind the aircraft ahead and to your right on taxiway bravo. Runway seven right taxi via echo and echo three, hold short of runway seven left, traffic landing. If the aircraft must cross an active runway before reaching the departure runway, the ground controller must coordinate this crossing with the local controller. This is accomplished by asking the local controller for permission to cross the active runway at a certain location. The local controller may approve the request, deny it, or approve it subject to some restrictions: GROUND CONTROL: Cross runway seven left at echo ten? LOCAL CONTROL: Cross runway seven left at echo ten approved. After the aircraft has crossed the runway, the ground controller must advise the local controller that the operation has been completed. At Phoenix, there are typically two ground controllers. One handles the taxiways on the north side of the airport and operates using frequency 119.75. The other handles the south side of the airport on 132.55. Assuming, in the example, that it is now time to let the aircraft depart, the flight crew would contact ground control. If the aircraft is parked at Terminal 4 and will be using runway 7L for departure, the flight crew must first contact north ground control on 119.75. After the crew confirms the aircraft’s identification and location, the ground controller would advise them to begin their taxi. SW-4, 09 APR 2009 to 07 MAY 2009 Figure 10–10. Phoenix Airport chart. SW-4, 09 APR 2009 to 07 MAY 2009 432 / CHAPTER 10 Operation in the National Airspace System / 433 Southwest eighteen ninety-four, taxi to runway seven left via taxiways charlie, sierra and echo. Contact south ground on one three two point five five when established on taxiway sierra. Upon crossing the bridge taxiway “sierra,” the south ground controller would monitor the aircraft’s progress all the way to the approach end of runway 7L, making adjustments or issuing additional instructions keeping ground traffic separated. Upon reaching the end of the approach end of runway 7L, the pilots would contact local control on 120.9 and advise ready for takeoff. Phoenix Tower, Southwest eighteen ninety-four, runway seven left ready for takeoff. Local Control It is the local controller’s responsibility to safely sequence departing aircraft into the local traffic flow while still complying with any departure instructions issued by the departure controller. The local controller is not permitted to depart an IFR aircraft without the approval of the departure controller. This approval may be received specifically for each aircraft, or routine departure instructions may be specified by facility procedures. Most radar-equipped facilities have devised a system that permits the local controller to depart an IFR aircraft without prior verbal coordination with the departure controller. This method of operation requires that a specific block of airspace be reserved for departing aircraft, and the local controller is authorized to depart aircraft into this area without prior coordination. The local controller still retains responsibility for the initial separation of IFR departures, however. When using this type of system, the approach controllers are responsible for keeping inbound aircraft separated from this departure area. The departure area is usually the shape of a wide fan or a narrow corridor (see Figure 10–11). This wedge of airspace usually extends from the ground up 120∞ Departure area 30∞ 30∞ 3,000–7,000 ft. 3–5 n mi Runway Figure 10–11. The departure fan used by the local controller to initially separate departures from arrivals. 434 / CHAPTER 10 to an altitude of 3,000 to 6,000 feet above the ground. As long as the clearance delivery controller has restricted the aircraft to the appropriate altitude and the local controller assigns a heading that will keep the aircraft within the confines of the departure area, no prior coordination between the local and departure controllers is needed. At Phoenix, when arriving and departing to the east, arrivals are sequenced for runways 7R and 8. Departures use runway 7L. Assuming that visual conditions exist, aircraft can depart runway 7L independently of arrivals on the other two runways. So long as the controller ensures both wake turbulence separation as well as runway separation (6,000⬘) between successive departures, SWA1894 can be cleared to depart. Southwest eighteen ninety-four, fly runway heading, runway seven left, cleared for takeoff. At the same time as takeoff clearance was being issued, the local controller would scan the bar code printed on the flight strip, indicating that the aircraft has departed. This would activate the flight data processing system and electronically “send” the flight strip to the appropriate departure controller. This action would also begin the process of sending the flight data downstream to every controller along the aircrafts route of flight (see Figure 10–12). Once the aircraft has departed and the controller has resolved any conflicts with local traffic, the pilot is directed to contact the departure controller. Since the appropriate frequency was previously issued by the clearance delivery controller, the local controller is not required to restate it. Figure 10–12. Bar code reader in control tower. Operation in the National Airspace System / 435 Southwest eighteen ninety-four, contact departure. Departure Control Depending on the complexity of the facility, departure control may be operated by the approach controller, separate control position, or could even be divided into a number of different subsectors. In any case, it is the responsibility of the departure controller to separate departing aircraft from all others while still complying with appropriate facility procedures. Once the aircraft has been changed to the departure controller’s frequency, this controller must radaridentify the aircraft and verify the accuracy of the aircraft’s mode C transponder, if the aircraft has one. It is the departure controller’s job to radar-identify the aircraft to ensure that the controller has a positive identification of the radar target. The easiest method used to radar-identify an aircraft is to observe a departing aircraft target within 1 mile of the takeoff runway end. The aircraft’s mode C altimeter function must also be verified. This is typically accomplished by the pilot stating his or her altitude on initial contact. Phoenix departure, Southwest eighteen ninety-four, one thousand five hundred climbing seven thousand. Assuming the controller has radar-identified the aircraft, the pilot will be so advised. If traffic permits an unrestricted climb, the pilot may be assigned a higher altitude (generally the top of the TRACON airspace or a lower altitude). If the aircraft needs to be turned on course, the controller will do so when able (see Figure 10–13). Southwest eighteen ninety-four Phoenix departure, radar contact, proceed on course, climb and maintain flight level two one zero. Once radar contact has been established and the pilot has been advised, the controllers are permitted to use radar separation. They are not prohibited from using nonradar separation if that provides an operational advantage though. At this point, the controller may vector the aircraft to join the route of flight while still complying with facility procedures and letters of agreement. The controller also attempts to clear the aircraft to climb to the pilot’s requested altitude as soon as is practical. If this is not possible because of a lack of jurisdiction or traffic conflicts, the aircraft will typically be cleared to the altitude closest to that filed by the pilot. If the aircraft will transit other subsectors within the terminal facility, the departure controller must either hand off or point out the aircraft to the appropriate controllers. Such handoffs are accomplished manually or through the use of automated procedures. If the aircraft is remaining at a fairly low altitude, it will usually be handed off to an adjoining terminal facility. But, if the aircraft will fly at a sufficiently high altitude, it is generally handed off to the appropriate ARTCC. SW-4, 09 APR 2009 to 07 MAY 2009 Figure 10–13. Phoenix Departure chart. SW-4, 09 APR 2009 to 07 MAY 2009 436 / CHAPTER 10 SW-4, 09 APR 2009 to 07 MAY 2009 Figure 10–13. (continued) SW-4, 09 APR 2009 to 07 MAY 2009 Operation in the National Airspace System / 437 438 / CHAPTER 10 Transfer of radar identification is the purpose of the “handoff.” So long as the aircraft is handed off from one controller to the next, without a loss of radar identification, the receiving controller can use radar separation rules without reestablishing radar identification. Phoenix departure control is assigned the airspace up to and including FL 210. As the aircraft proceeds along the San Juan 3 departure procedure, the departure controller will attempt, traffic permitting, to climb the aircraft to FL 210. Prior to reaching that altitude, departure control will then hand the airplane off to Albuquerque ARTCC (ZAB). En route Separation The first en route controller who will separate the aircraft receives flight progress strip data shortly after the clearance delivery controller enters the departure time into the computer or after radar detects the aircraft’s transponder and sends a message directly to the ARTCC computer. Subsequent controllers then receive updated flight data approximately 15 to 30 minutes before the aircraft enters each sector (see Figure 10–14). The flight data will then be displayed to the controller either using paper flight progress strips or using the textual URET flight planning function. The en route controllers use the information on the flight strip to prepare for the separation of that flight. Once the ARTCC radar system detects the aircraft’s transponder signal, a data block containing the aircraft’s call sign, altitude, and airspeed appears on the controller’s display. At the point delineated in the appropriate letter of agreement, the departure controller hands off the aircraft to the ARTCC controller. Once the en route controllers have accepted a handoff, they are responsible for separating that aircraft from all others within the sector. This may be somewhat difficult if the aircraft is sufficiently low and far enough away from Figure 10–14. Phoenix departure traffic. Operation in the National Airspace System / 439 an ARTCC radar site that it remains undetected by radar. In such cases, the aircraft will not appear on the ARTCC controllers’ radar display and must be separated using nonradar procedures. If the aircraft is operating below 18,000 feet MSL, it is typically separated by controllers responsible for low-altitude aircraft, known as low-sector controllers. East of the Mississippi river, it is possible for some lower flying IFR aircraft to continuously fly from one TRACON airspace to the next, without ever entering the airspace of an ARTCC (see Figure 10–15). ALBUQUERQUE ARTCC AND PHOENIX TRACON LETTER OF AGREEMENT (excerpted) PURPOSE: This letter of agreement delegates airspace, defines responsibilities, and establishes procedures between Albuquerque ARTCC (ZAB) and Phoenix TRACON (P50) for approach control service in the Phoenix, AZ terminal area. CANCELLATION: Albuquerque ARTCC and Phoenix TRACON letter of agreement dated August 3, 1981. SCOPE: The procedures herein are for the purpose of conducting IFR operations between Phoenix TRACON and Albuquerque ARTCC within the airspace delegated to each facility. PROCEDURES: General Deviations from procedures contained in this letter of agreement are authorized on an individual aircraft basis after coordination between involved controllers. Departures. P50 TRACON shall: 1. Provide ZAB with five nm radar separation, constant or increasing, between aircraft. 2. Hand off aircraft to ZAB sector 38 climbing to FL210 or their assigned lower altitude. 3. Aircraft entering ZAB airspace shall be issued frequency 132.9. ZAB shall: 1. Climb aircraft above FL210 as soon as practicable. 2. Assign appropriate departure procedures or issue vectors that place the aircraft through one of the departure gates. 3. Keep aircraft on their assigned heading, route and airspeed while still within P50 airspace. Arrivals ZAB shall: 1. Assign appropriate arrival routes or issue vectors that place the aircraft through one of the arrival gates. 2. Aircraft inbound to PHX shall be assigned an altitude of 12,000⬘ prior to handoff. 3. Provide P50 with five nm radar separation, constant or increasing, between aircraft. 4. Assign appropriate frequencies as advised by P50. P50 Tracon shall: 1. Keep aircraft on their assigned heading, route and airspeed while still within ZAB airspace. Figure 10–15. Phoenix TRACON/Albuquerque ARTCC Letter of Agreement. 440 / CHAPTER 10 However, if the aircraft climbs to a higher altitude, it will usually be handed off to a high-altitude control sector. Once the aircraft reaches its assigned cruising altitude, it continues toward its destination, being handed off to different controllers as it crosses sector boundaries. The controller constantly monitors aircraft separation and makes routing adjustments as needed using the radar display and URET predictions to ensure separation. If the pilot has any rerouting requests or the controller needs to issue any new routes, time permitting, the URET will be used in a trial flight planning mode to determine if any possible conflicts might occur. The first of many ZAB sectors the example flight will transit is ZAB sector 38, which borders and overlays PHX departure controls airspace. While the flight is still climbing to FL 210, the PHX departure controller will initiate a radar handoff to ZAB sector 38. This is typically accomplished using the automation equipment. In general, as long as controllers are conforming to the appropriate letter of agreement, an automated handoff is the preferred method of transferring radar identification. The PHX departure controller initiates the handoff to the center, essentially causing the aircraft’s data block to begin flashing on sector 38’s screen. With a simple click of the trackball or a couple of keystrokes, the center controller accepts the handoff, and the data block flashes on the PHX departure controller’s radar indicating acceptance. Once all potential TRACON traffic conflicts have been resolved, the departure controller advises the pilot to contact the center controller. Southwest eighteen ninety-four, contact Albuquerque Center on one three two point niner. This is the transfer of communications. When the aircraft comes up on ZAB sectors 38’s frequency, if traffic permits, the controller will advise the pilot to climb to their final cruising altitude. Southwest eighteen ninety-four, climb and maintain flight level three five zero. The transfer of control does not occur until the aircraft actually enters sector 38. After it does, if there is any conflicting traffic while en route, the aircraft might be turned to avoid it or stopped at an intermediate altitude until the traffic has passed. In any case, the pilot will be issued the instruction followed by the reason for the alternate clearance. Southwest eighteen ninety-four, climb and maintain flight level three one zero, traffic opposite direction, an Airbus 330 flight level three two zero westbound. Expect flight level three five zero in two zero miles. Southwest eighteen ninety-four, turn two zero degrees right, traffic passing on your left is an Airbus 330 flight level three two zero westbound. Expect a vector back to the airway in two zero miles. As the aircraft flies toward the destination airport, handoffs will occur between subsequent sectors. Some will be within the center itself, and other handoffs will be between adjacent ARTCCs (see Figure 10–16). While flying Operation in the National Airspace System / 441 Figure 10–16. Aircraft en route. within each sector, it is the controller’s responsibility to maintain separation with other aircraft climbing or descending within the airspace and level traffic flying in the same, opposite, or crossing directions while complying with all relevant procedures. Once the aircraft is within 500 to 1,000 miles of the destination airport, traffic flow management programs begin to add to the complexity of the en route controller’s task. If long-term delays are expected at Indianapolis, the departure might have been issued a ground delay. But, if unexpected weather or other conditions causes a temporary loss of airport capacity at Indianapolis, the aircraft might need to be delayed en route. There are two basic methods for managing the flow of traffic into an impacted airport; miles in trail restrictions and metering. As aircraft approach the destination airport, each successive controller begins to assign progressively lower altitudes. If the arrival airport is particularly busy, some form of traffic management might be needed. FAA traffic management programs attempt to match the inbound flow of traffic to the airport’s acceptance rate, the calculated rate at which the airport can absorb traffic. If, for instance, calculations show that a particular airport can handle sixty aircraft operations in 1 hour, its theoretical acceptance rate is one per minute. A general rule of thumb is that a single runway can handle thirty arrivals per 442 / CHAPTER 10 hour (one every 2 minutes) if the runway is being used for both arrivals and departures. If the runway is being used solely for arrivals, a 1-minute interval between aircraft can probably be maintained. This would permit the runway to handle sixty aircraft per hour. If two aircraft are scheduled to arrive at the airport at the same time, one of the aircraft will be delayed for at least 1 minute. Such delays place a burden on the approach controller, since only a limited amount of airspace is available to maneuver aircraft. It becomes even more difficult to delay aircraft when more than two flights are scheduled to arrive at the same time. In this situation, the approach controller rapidly runs out of airspace in which to maneuver aircraft (a fairly common situation that occurs routinely wherever airlines operate hub-and-spoke scheduling systems). In general, it is FAA procedure to ensure that most of the delay is assigned while en route and not in the busy terminal airspace. It is impossible to accurately project all flight paths with minute-by-minute accuracy, so generally it is assumed that, if needed, aircraft can be delayed within TRACON airspace by about 5 minutes. But, if more than 5 minutes of delay needs to be assigned to any particular aircraft, it must be accomplished in ARTCC airspace. FAA procedures require that this delay be imposed far enough out so when the aircraft crosses an imaginary arc about 200 nm from the destination airport, all of the delay assigned to that flight has already been established (see Figure 10–17). Figure 10–17. Aircraft nearing destination airport and 200 nm ring. Operation in the National Airspace System / 443 Miles in Trail Restrictions The minimum longitudinal separation for aircraft in en route airspace is 5 nm. For aircraft flying at or about 600 knots, this linear separation equates to about 30 seconds of separation. Assume, for example, that a flow of traffic is flying toward a destination airport from four directions and the airport can safely handle sixty aircraft per hour (or one per minute). If the traffic is more or less evenly distributed and spaced, fifteen aircraft per hour is the limit for the aircraft coming in from each direction. To ensure that the aircraft arrive in an orderly flow, the TRACON would ask that the four flows of traffic evenly space each of their inbound aircraft 4 minutes (or 8 miles apart). This is called a miles in trail (MIT) restriction. If the airport could safely land only thirty aircraft per hour, they would most likely ask the center to double the separation to fifteen or 16 miles in trail. Metering Metering is similar in its results but is a time-based traffic management system. The en route metering program calculates the airport’s acceptance rate and determines the number of aircraft that can be handled in any given 5-minute period. If it is determined that the calculated airport acceptance rate will be exceeded, the en route metering software at the ARTCC begins to calculate appropriate delay strategies to temporarily reduce the number of inbound aircraft. The metering program dynamically determines specific times that aircraft should cross en route fixes or distance arcs in order to delay each aircraft the required interval. It then becomes each ARTCC radar controller’s responsibility to ensure that the aircraft cross these fixes at the appropriate times. A rough rule of thumb for en route delays is that approximately 1 minute of delay can be established for every 30 to 50 nautical miles that an airplane flies. Therefore, if the aircraft needs to be delayed 10 minutes for example, this delay needs to start being imposed 500 to 700 miles from the destination airport such that the airplane crosses the 200-nm arc at the appropriate time (see Figure 10–18). The ATCSCC in conjunction with traffic management unit (TMU) controllers at each center determines the appropriate delay to be assigned to each aircraft, then parses that delay out to each sector. The delay can be displayed as either a time over a fix or a total delay needed to be extracted from each aircraft. In the former, a list of aircraft IDs, metering fixes, and times to cross each fix are displayed directly on the center controller’s display. It then becomes the controller’s job to ensure that the aircraft crosses the assigned fix as close as possible to the assigned crossing time. Another method involves having the computer display in real time, which is the actual number of minutes that each aircraft still needs to be delayed. This number is prominently placed next to the aircraft’s data block. Using this system, it then becomes the controller’s option how to establish the delay, with the only requirement being that the delay be imposed prior to handing the aircraft off to the next sector. Delay Techniques The three methods of establishing delay include vectoring, speed control, or crossings restrictions. When vectoring an aircraft for a delay, the controller issues a turn that takes the aircraft off course a defined distance and then allows 444 / CHAPTER 10 Metering fixes Metering fixes Cornerpost fixes Airport Cornerpost fixes Metering fixes Metering fixes Figure 10–18. Traffic flow arriving in a major terminal. Aircraft first cross designated metering fixes before crossing the cornerpost fixes. the aircraft to return to course. This technique is commonly used if there is sufficient space within which to accomplish it inside the sector airspace. Southwest eighteen ninety-four, turn left heading zero six zero, vector for spacing. Issuing speed restrictions is another method of en route spacing. Slowing down one aircraft at the head of a line of flowing traffic causes the whole line to slow down, which can cause a problem if those aircraft are flying to a different airport that doesn’t have any flow control restrictions. Southwest eighteen ninety-four reduce speed to three one zero. Asking a pilot to cross a fix at a specific time is another commonly used technique. With this technique, speed correction is the pilot’s responsibility, but it needs to be monitored to ensure pilot compliance. Operation in the National Airspace System / 445 Southwest eighteen ninety-four, cross Bible Grove at zero two five six. Our aircraft will continue along the route of flight passing from one sector to the next, leaving Albuquerque ARTCC’s airspace, transiting that of Kansas City center (ZKC), and finally entering Indianapolis center’s (ZID) airspace. All of these controllers are required to safely separate aircraft while complying with any and all applicable flow management instructions. Approach Control About 200 miles from the Indianapolis airport, the controllers will begin to descend the aircraft while beginning to sequence SWA1894 into the traffic flow for the Indianapolis airport. This must all be accomplished while complying with the procedures described in the Indianapolis Center/Indianapolis Tower Letter of Agreement (see Figure 10–19). In particular, the center controller must ensure that SWA1894 enters Indianapolis approach control airspace either at or descending to 11,000 feet and enters over one of the designated arrival fixes. The Kelly intersection, which is about 20 miles southwest of Indianapolis, and part of the RACYR ONE STAR, is one such fix (see Figure 10–20). Indianapolis TRACON controllers procedurally separate inbound and outbound aircraft using a modification of a “box” system of procedural separation. In a typical box configuration, the letter of agreement describes a box that is drawn around the affected TRACON’s airspace. Each corner of the box, known as a cornerpost, is delineated by an intersection or navaid. At Indianapolis, the cornerposts are delineated by the Jells and Antti intersections to the northwest, Clang to the northeast, the Shelbyville (SHB) VOR at the southeast, and the Kelly intersection to the southwest. Where box systems are used, the letter of agreement specifies that every inbound IFR aircraft must enter the approach control’s airspace at one of the cornerposts. These areas are known as arrival gates (see Figure 10–21). The letter of agreement also specifies that departures must remain clear of the cornerposts and depart the area through the sides of the box. The sides of the box are known as departure gates. When the handoff has been accepted by the Indianapolis approach controller, SWA1894 is descended to 11,000 feet (as per the letter of agreement) and is advised to contact the approach controller. Southwest eighteen ninety-four, descend and maintain one one thousand, contact Indianapolis approach control on one one niner point three. Indianapolis Approach Control The procedures at Indianapolis specify that as many as seven different controllers may be assigned approach and departure control responsibilities, corresponding to six control sectors (see Figures 10–22 [page 449] and 10–23 [page 450]). Two of these sectors are designated as arrival sectors and are known as east arrival and west arrival, whereas the other four are departure sectors known as north, south, east, and west departure. In this scenario, we will assume that runway 5L is the primary runway in use at Indianapolis International Airport. In this runway configuration, the two arrival controllers are assigned the airspace on both sides of runway 5L. Each departure 446 / CHAPTER 10 INDIANAPOLIS TOWER AND INDIANAPOLIS CENTER LETTER OF AGREEMENT SUBJECT: TERMINAL AREA CONTROL PROCEDURES EFFECTIVE: January 1, 1989 PURPOSE: To prescribe procedures to be used between Indianapolis ATCT and Indianapolis ARTCC. CANCELLATION: Indianapolis ATCT and Indianapolis ARTCC Letter of Agreement dated January 1, 1984. SCOPE: The procedures herein are for the purpose of conducting IFR operations between Indianapolis ATCT and Indianapolis ARTCC. RESPONSIBILITY: Indianapolis ARTCC delegates to Indianapolis ATCT the authority and responsibility for control of IFR terminal and en route traffic at 10,000 feet and below. ARRIVAL PROCEDURES: CLEARANCE LIMIT The destination airport shall be the arrival airport. Indianapolis ARTCC shall clear arrivals via the metering fixes depicted on attachment #1. ROUTES The filed route shall be the arrival route unless suspended by either facility. FDEP shall constitute approval and coordination. ALTITUDES Arrivals landing at any airport in Indianapolis ATCT’s delegated airspace shall be cleared over one of the arrival fixes either level at or descending to 11,000 feet. Indianapolis ATCT may descend these aircraft below 11,000 feet once the transfer of communication has been accomplished. DEPARTURE PROCEDURES: Indianapolis ATCT shall ensure that departures are handed off with at least 5 miles radar separation that is constant or increasing. Aircraft filing for 11,000 feet or higher must be restricted to 10,000 feet until coordinated with Indianapolis ARTCC. Indianapolis ATCT shall ensure that departures cross one of the four departure gates shown on attachment #1 as NOIND, EAIND, SOIND, and WEIND. FREQUENCIES Indianapolis ARTCC to Indianapolis ATCT - 121.35 mHz or 285.65 mHz Indianapolis ATCT to Indianapolis ARTCC - 132.20 mHz or 307.10 mHz Figure 10–19. Letter of Agreement. EC-2, 09 APR 2009 to 07 MAY 2009 Figure 10–20. RACYR One standard terminal arrival route. EC-2, 09 APR 2009 to 07 MAY 2009 Operation in the National Airspace System / 447 448 / CHAPTER 10 Figure 10–21. The arrival gates used by Indianapolis approach control. controller is assigned a 90° segment of airspace delineated by the extended centerlines of runway 5L-23R and 14-32. In general, the arrival controllers are delegated the airspace at 3,000 feet, 7,000 feet, and 10,000 feet in all areas and from the surface up to 7,000 feet in the area immediately surrounding the ILS runway 5L and 5R approaches. The departure controllers are assigned the remaining airspace for their use. A short description of each area and its purpose follows. Areas 1, 1A, and 1B lie primarily between the approach gates and the airport. Within these areas, the approach controller descends inbound aircraft to 10,000 feet while the departure controller climbs departing aircraft to 9,000 feet. Area 2 is designated as a departure area and lies between the airport and the departure gates. The approach controller is not typcially authorized to use any of this airspace. Area 3 is used by the approach controller to vector aircraft for the ILS approach, and inbound aircraft can descend to 3,000 feet within this area. Area 4 is used for the ILS approach itself, and inbound aircraft are Operation in the National Airspace System / 449 Figure 10–22. Indianapolis approach control radar display. authorized to operate between the surface and 7,000 feet. Areas 6A and 6B are used by the local controller for departing aircraft and constitute the departure fan. Area 6A is used by propeller-driven aircraft, which are initially restricted to 2,500 feet. Area 6B extends to 6,000 feet and is used for jet departures. The area above these altitudes is the responsibility of the departure controllers. These altitude assignments are summarized in Table 10–1. Typically, every inbound aircraft crosses one of the cornerposts either level at or descending to 11,000 feet. Once the aircraft has entered Indianapolis TRACON’s assigned airspace, the arrival controller is permitted to descend the aircraft to 10,000 feet. Every aircraft inbound to Indianapolis is vectored toward the airport and sequenced behind other inbound aircraft. Once the aircraft is within about 15 nautical miles of the airport (area 1), the arrival controller is authorized to descend the aircraft to 7,000 feet if coordination has been accomplished with the appropriate departure controller. Southwest eighteen ninety-four, descend and maintain seven thousand, vector for the ILS runway five left approach. When SWA1894 is within about 15 miles of the airport, it has entered area 1B, where the arrival controller may use the airspace extending from 7,000 feet to 3,000 feet MSL. At this point, the aircraft is usually turned onto the ILS final approach course. Once in this position, traffic permitting, the aircraft will be descended to 3,000 feet in preparation for the ILS approach. Southwest eighteen ninety-four, fly heading zero four zero, descend and maintain three thousand. 450 / CHAPTER 10 Figure 10–23. Arrival and departure areas as specified in Indianapolis facility procedures. Aircraft coming in from one of the other three cornerpost fixes would be placed on either a left or right extended downwind leg. Once the aircraft is abeam the airport, the pilot is advised to contact the final approach controller. The final controller is charged with merging the left and right downwind traffic with the straight for the final ILS approach. The final controller will determine the approach sequence and will space the aircraft using either vectors or speed restrictions. When SWA1894 is in the proper position, adequately separated from both preceding and following Operation in the National Airspace System Table 10-1. Area 451 / Altitude Assignments at Indianapolis SFC-2,500 3,000 3,500 4,000 5,000 6,000 7,000 8,000 9,000 10,000 1 D A* D D D D A D D A 1A D A* D D D D A D D A 1B D D A A A A A D D A 2 D D D D D D D D D D 3 D A A A A A A D D A 4 A A A A A A AD D A A 6A L A D D D D A D D A 6B L L L L L L A D D A A⫽A r r iv a l contr olle r ; D ⫽D e pa r t ur e cont rol l er; L⫽ L o ca l co n t ro l l er; * ⫽ V FR a l t i t u d es. aircraft, the controller permits the aircraft to intercept the runway 5L localizer and complete the approach (see Figure 10–24). Southwest eighteen ninety four, seven miles from CENEK, turn left heading zero three zero, intercept the final approach course at or above three thousand, cleared for the ILS runway five left approach. Monitor tower on one two seven point eight two and report Cenek inbound. At all times while being vectored for the ILS approach, inbound aircraft are procedurally separated from departing aircraft. The only coordination involved between the approach and departure controllers occurs when the arrival controller descends inbound aircraft from 10,000 feet to 7,000 feet. One of the limitations on the arrival controllers is that very little airspace is assigned for maneuvering aircraft close to the runway. The arrival controllers must keep each aircraft within the confines of areas 1B, 3, and 4 while descending the aircraft to 3,000 feet MSL. Because of this lack of airspace, the arrival controllers at Indianapolis become highly skilled at predicting the future flight paths of aircraft and judiciously use speed adjustments to safely sequence arrival aircraft while still confining these aircraft to the specified airspace. Local Control At Indianapolis tower, the local controller is responsible for sequencing SWA1894 into the departure flow of traffic but has little flexibility to maneuver the aircraft without coordinating with the controllers in the TRACON. If circumstances require, the local controller can clear SWA1894 to land on the parallel runway, runway 5R, but may not assign SWA1894 to any other runway without coordinating with the controllers in the TRACON. Southwest eighteen ninety four, cleared to land runway five left. Traffic is a Cessna ahead and to your right landing runway five right. 452 / CHAPTER 10 Figure 10–24. ILS runway 5 left approach at Indianapolis. Operation in the National Airspace System / 453 Once SWA1894 has landed, the local controller advises the pilot to contact the ground controller, who clears the aircraft to taxi to the terminal. Example of a VFR Flight Lafayette to Champaign Pilots flying VFR are not required to file a flight plan but are encouraged by the FAA to do so. The flight plan itself is not directly transmitted to air traffic control facilities but is instead used primarily to assist in the location of lost aircraft. Pilots who contact a flight service station for a VFR flight will receive essentially the same weather briefing information as that given to an IFR pilot but will have the briefing specifically arranged for them. Since Lafayette is within the Terre Haute AFSS’s area of responsibility, the pilot of N252MN would typically call the Terre Haute Flight Service Station for this weather briefing. At the conclusion of the weather briefing, the FSS specialist asks whether the pilot wishes to file a flight plan. If the pilot does, the briefer enters the appropriate information into the FSS computer (see Figure 10–25). Ground Control When N252MN is ready to depart Lafayette, the pilot first contacts the Lafayette ground controller and receives taxi clearance (“N252MN, taxi to runway one zero”). After taxiing to the active runway, the pilots contact the local controller for departure instructions. The controller’s responsibility to VFR pilots is to provide appropriate runway separation to each aircraft (“N252MN, Lafayette tower, turn right on course, runway one zero cleared for takeoff”). Once N252MN is airborne and clear of the Lafayette Class D airspace, the pilots contact the Terre Haute Flight Service Station to “activate” their VFR flight plan. A VFR flight plan is not activated automatically; it is up to the pilots to initiate contact with the appropriate ATC facility (usually a flight service station) to activate the flight plan. The pilots, for consistency, can contact the FSS in various ways. The first method is to use a remote communications outlet (RCO) to the flight service station. An RCO permits pilots to communicate with distant flight service stations using a single frequency. The radio transmitter and receiver are located at an airport distant from the flight service station (in this case at the Lafayette Airport) but are connected to it by telephone communications equipment. The FSS specialist at Terre Haute can communicate with aircraft on the ground or within the immediate vicinity of Lafayette using the Lafayette RCO. Remote communications outlet frequencies are printed on VFR navigation charts (see Figure 10–26). Another method of communicating with a flight service station requires the pilot to transmit on one frequency and receive the reply from the flight service specialist on another frequency assigned to a navigation aid, usually a VOR. These facilities can also be found on VFR navigation charts; the appropriate transmitting frequency is next to the navaid followed by the letter R 454 / CHAPTER 10 Figure 10–25. Sample VFR flight plan for N252MN’s simulated VFR flight from Lafayette to Champaign. Operation in the National Airspace System / 455 Figure 10–26. A remote communications outlet as depicted on a sectional chart. (which indicates FSS receive only). The receiver is remotely connected to the flight service station via telephone equipment. The FSS specialist in turn communicates with the pilot by transmitting on the VOR frequency, which does not impair the operation of the VOR. A third method of communicating with an FSS specialist requires that the aircraft be within range of the FSS itself. Besides having their own discrete frequencies, almost all FSSs have the capability of communicating using 122.2 mHz. If pilots are unsure of local FSS frequencies, they can almost always establish communication on 122.2 mHz. At Lafayette, the pilots of N252MN would probably contact Terre Haute FSS on 122.35 mHz using a remote communications outlet. To activate their flight plan, the pilots must advise the FSS specialist of their departure time from Lafayette. The FSS specialist then enters the departure information into the FSS computer. This causes the following information to be sent to the flight service station with responsibility for Champaign, which in this case is the St. Louis FSS: Aircraft identification. Aircraft type. Destination. Estimated time of arrival (ETA) at Champaign. The St. Louis FSS computer returns an acknowledgment message to Terre Haute Flight Service. Once the acknowledgment message has been sent, N252MN becomes the responsibility of St. Louis if it becomes overdue. En Route The pilots of N252MN are not required to establish contact with any ATC facility while en route to Champaign. If the aircraft is within range of a radar-equipped facility, however, the pilots can contact that facility and 456 / CHAPTER 10 request radar traffic advisories. Traffic advisories offered to VFR aircraft are the same as those offered to IFR aircraft; VFR traffic advisories are offered to pilots on a workload-permitting basis only. If the pilots of N252MN were to encounter questionable or changing weather conditions en route, a local flight service station could offer them some assistance. The FSS specialist could offer weather advisories, forecasts, and pilot reports of adverse weather conditions. Contact could be made with the flight service station through an RCO or direct communications with an FSS using 122.2 mHz, or the pilot could request en route flight advisory service (EFAS). EFAS is a weather advisory service provided by certain flight service stations to en route VFR or IFR aircraft (see Figure 10–27). At these specially equipped stations, an individual controller is on duty to provide timely weather information to en route aircraft. EFAS is not intended to be used for filing or opening flight plans; it is designed to be used by pilots as a weather exchange service only. The EFAS specialist has all of the most pertinent weather information available, including real-time weather radar provided by the National Weather Service (see Figure 10–28). In addition, the EFAS specialist constantly solicits weather information from area pilots and controllers. The EFAS specialist is thus able to provide timely weather and safety-related information to those pilots who need it most. EFAS operates using a common frequency of 122.0 mHz. Pilots who desire to contact the EFAS specialist should broadcast their position relative to the nearest VOR using this frequency. Since every EFAS specialist monitors 122.0, the controller with the appropriate jurisdiction will answer the pilot and provide the required information. EFAS has been enormously successful, and therein lies its only major problem. Since EFAS operates on a common frequency nationwide, it is possible for high-flying aircraft to interfere with EFAS transmissions over a number of states at one time. To alleviate this problem, the FAA is beginning a program of establishing discrete frequencies for aircraft using EFAS above 18,000 feet MSL. High-altitude EFAS, as it is known, will provide a separate frequency for use by aircraft operating at or above FL 180 within each ARTCC area. Champaign Approach Control Once N252MN is within Champaign approach control’s area of radar coverage (about 40 nautical miles), the pilots can contact the Champaign TRACON for radar traffic advisories. Although contact is not mandatory at this distance, it is recommended in order to enhance safety around busy terminal areas. The pilots of N252MN are required to contact Champaign approach prior to entering the Champaign Class C airspace, however (see Figure 10–29). Before the Champaign controller can provide radar service, N252MN must be radar identified. This is accomplished in the same manner as with an IFR aircraft. The controller notes the pilot’s reported position, assigns N252MN a discrete transponder code, and verifies that the ARTS-II computer properly acquires the code and generates an appropriate data block. In addition, the controller may ask the pilot to activate the Ident feature of the transponder (“N252MN, squawk four one two one and ident”). Operation in the National Airspace System Figure 10–27. En route flight advisory service. / 457 458 / CHAPTER 10 Figure 10–28. Flight service station controller. When N252MN has been radar identified, the controller advises the pilots of their position and of the procedure that can be expected when entering the traffic pattern at Champaign (“N252MN, radar contact two seven miles northeast of Champaign. Enter a right base for runway three two left”). The approach controller then provides radar traffic advisories to N252MN until the aircraft is within Class C airspace. Once N252MN enters Class C airspace, the controller is required to Sequence every aircraft inbound to the primary airport (Champaign). Provide standard IFR separation between IFR aircraft. Provide Class C separation criteria between IFR and VFR aircraft. Provide traffic advisories and safety alerts between VFR aircraft. Separation provided between IFR and VFR aircraft is not as stringent as that applied to IFR aircraft. It is assumed that because VFR conditions exist, both pilots can assist to ensure separation. Within Class C airspace, the controller is required to provide one of the following methods of separation between an IFR and a VFR aircraft: Visual separation A 500-foot vertical separation Lateral or longitudinal conflict resolution When providing conflict resolution, the controller must ensure that the displayed radar targets do not touch each other. In addition, both aircraft must be issued the applicable traffic advisories concerning the other aircraft. A radar controller is not required to separate two VFR aircraft but must offer traffic advisories and safety alerts. A safety alert is defined by the Operation in the National Airspace System / 459 Figure 10–29. Champaign Class C airspace. Aeronautical Information Manual as a condition in which, in the controller’s judgment, the aircraft are in unsafe proximity. Whenever this condition arises, the controller must issue a traffic advisory and offer the pilots an alternate course of action that should resolve the situation. It is expected that because both aircraft are in VFR conditions, they will assist in the conflict resolution (“N252MN, traffic alert, traffic twelve o’clock and one mile, eastbound at three thousand five hundred. Advise you turn left heading two four zero or climb to four thousand immediately”). Once N252MN has been appropriately separated from other inbound and outbound aircraft, the controller must coordinate N252MN’s arrival sequence with the west arrival controller. The pilots of N252MN are instructed to follow another aircraft or are vectored to ensure proper spacing behind that aircraft. When the sequence has been established and ensured, the pilots are advised to 460 / CHAPTER 10 contact the local controller (“N252MN, traffic you are following is a Lear at twelve o’clock and five miles, contact the tower on one two zero point four”). Local Control At this point, it becomes the local controller’s responsibility to sequence N252MN into the local flow of traffic. As with IFR arrivals, when N252MN is within 3 miles of the airport, the local controller can maneuver the aircraft to another runway or to follow a preceding aircraft. When it is appropriate, the local controller issues landing clearance. After N252MN has landed, the ground controller assumes responsibility for taxi instructions. Closing the Flight Plan After N252MN has landed at Champaign, the pilots contact St. Louis FSS to cancel their flight plan. This contact can be made using the telephone or using the RCO at Champaign. The St. Louis FSS specialist closes N252MN’s flight plan on receipt of this message from the pilot. Overdue Aircraft If 30 minutes have elapsed since N252MN’s estimated time of arrival at Champaign and the St. Louis FSS specialist has not received N252MN’s flight plan cancellation, N252MN is considered overdue. Once an aircraft is classified as overdue, search and rescue (SAR) procedures are instigated. During search and rescue operations, the destination FSS is responsible for initiating every attempt to locate the aircraft. The first action that the St. Louis controller takes is to send a QALQ message to every FAA facility at an airport where N252MN may have landed. In addition, the QALQ message is sent to the departure FSS (Terre Haute) and to every ARTCC within the area. A QALQ message is a request for information concerning the overdue aircraft. Any facility that receives a QALQ must briefly check with every controller and examine recent flight strips to determine whether any contact has been made with the overdue aircraft. Each of these facilities is required to answer the QALQ request, even if no contact has been made with N252MN. On receipt of a QALQ message, the departure FSS transmits all the pertinent flight plan information concerning N252MN to the St. Louis controller. This information is also transmitted to every facility that might have had contact with N252MN. Information Request If the replies to the QALQ request are all negative, meaning that no FAA facility in the nearby area has located N252MN, St. Louis FSS transmits an information request (INREQ) to the departure FSS, to every flight watch FSS along N252MN’s route of flight, to other FSSs or ARTCCs along N252MN’s planned route of flight, and to the Rescue Coordination Center (RCC) with responsibility for the area through which N252MN would have been flying. In this example, the appropriate RCC is Langley Air Force Base in Virginia. On receipt of an INREQ message, every facility begins a check of facility records to determine whether radio contact was made with N252MN. Every FAA facility along N252MN’s route of flight, such as flight service stations, Operation in the National Airspace System / 461 towers, and ARTCCs, is also contacted to determine whether communication with N252MN occurred. At the conclusion of these checks, a reply message is transmitted to St. Louis FSS describing the results of the search. Alert Notice If the replies to the INREQ are negative, the St. Louis FSS specialist transmits an alert notice (ALNOT) to every FAA facility within 50 miles of N252MN’s proposed route of flight. These facilities then conduct a communications search of every airport within their immediate vicinity. In most cases, the airport manager or operator is telephoned, and this individual conducts a visual search of the airport property. If no one can be contacted at the airport, local law enforcement personnel are requested to check for N252MN at the airport. In addition, flight service stations within this area transmit a request over the appropriate frequencies asking every airborne aircraft to monitor the emergency frequency (121.5 mHz or 243.0 mHz) and listen for emergency communications or a transmission from the emergency locator transmitter (ELT) on board N252MN. If an hour has elapsed since the original ALNOT transmission, the St. Louis FSS contacts the Rescue Coordination Center and provides all the pertinent information about that flight to the RCC officer. If N252MN has not been located by this time, the U.S. Air Force assumes complete responsibility for locating N252MN and may initiate a ground and air search for the aircraft, using the Civil Air Patrol. KEY TERMS acceptance rate advisory database Air Traffic Control System Command Center (ATCSCC) alert notice (ALNOT) arrival gates automated flight service station (AFSS) coded departure routes (CDR) conflict resolution departure controller departure gates Emergency locator transmitter (ELT) en route flight advisory service (EFAS) expect departure clearance time (EDCT) final controller Flight Data Center (FDC) flow constrained areas (FCA) full route clearance (FRC) high-altitude EFAS information request (INREQ) metering miles in trail notices to airmen (NOTAMs) playbook router QALQ message radar traffic advisories remote communications outlet (RCO) Rescue Coordination Center (RCC) safety alert search and rescue (SAR) severe weather avoidance plan (SWAP) traffic management unit (TMU)