Chapter 8 - The Nation Airspace System

Introduction

The National Airspace System (NAS) is the network of United States (U.S.) airspace: air navigation facilities, equipment, services, airports or landing areas, aeronautical charts, information/services, rules, regulations, procedures, technical information, manpower, and material. Included are system components shared jointly with the military. The system’s present configuration is a reflection of the technological advances concerning the speed and altitude capability of jet aircraft, as well as the complexity of microchip and satellite-based navigation equipment. To conform to international aviation standards, the U.S. adopted the primary elements of the classification system developed by the International Civil Aviation Organization (ICAO).

This chapter discusses airspace classification; en route, terminal, approach procedures, and operations within the NAS.

Airspace Classification

Airspace in the U.S. is designated as follows: [figure 8-1]

Class A—Generally, that airspace from 18,000 feet mean sea level (MSL) up to and including flight level (FL) 600, including the airspace overlying the waters within 12 nautical miles (NM) of the coast of the 48 contiguous states and Alaska. Unless otherwise authorized, all pilots must operate their aircraft under instrument flight rules (IFR).

National Airspace System (NAS): International Civil Aviation The common network of U.S. Organization (ICAO): The United airspace — air navigation facilities, Nations agency for developing the equipment and services, airports or principles and techniques of landing areas; aeronautical charts, international air navigation, and information and services; rules, fostering planning and development regulations and procedures, technical of international civil air transport. information, and manpower and material.

Class B—Generally, that airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest airports in terms of airport operations or passenger enplanements. The configuration of each Class B airspace area is individually tailored and consists of a surface area and two or more layers (some Class B airspace areas resemble upside-down wedding cakes), and is designed to contain all published instrument procedures once an aircraft enters the airspace. An air traffic control (ATC) clearance is required for all aircraft to operate in the area, and all aircraft that are so cleared receive separation services within the airspace.

Class C—Generally, that airspace from the surface to 4,000 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower, are serviced by a radar approach control, and have a certain number of IFR operations or passenger enplanements. Although the configuration of each Class C area is individually tailored, the airspace usually consists of a surface area with a 5 NM radius, an outer circle with a 10 NM radius that extends from 1,200 feet to 4,000 feet above the airport elevation and an outer area. Each person must establish two-way radio communications with the ATC facility providing air traffic services prior to entering the airspace and thereafter maintain those communications while within the airspace.

Class D—Generally, that airspace from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration of each Class D airspace area is individually tailored and when instrument procedures are published, the airspace will normally be designed to contain the procedures. Arrival extensions for instrument approach procedures (IAPs) may be Class D or Class E airspace. Unless otherwise authorized, each person must establish two-way radio communications with the ATC facility providing air traffic services prior to entering the airspace and thereafter maintain those communications while in the airspace.

Class E—Generally, if the airspace is not Class A, Class B, Class C, or Class D, and it is controlled airspace, it is Class E airspace. Class E airspace extends upward from either the surface or a designated altitude to the overlying or adjacent controlled airspace. When designated as a surface area, the airspace will be configured to contain all instrument procedures. Also in this class are federal airways, airspace beginning at either 700 or 1,200 feet above ground level (AGL) used to transition to and from the terminal or en route environment, en route domestic, and offshore airspace areas designated below 18,000 feet MSL. Unless designated at a lower altitude, Class E airspace begins at 14,500 MSL over the U.S., including that airspace overlying the waters within 12 NM of the coast of the 48 contiguous states and Alaska, up to but not including 18,000 feet MSL, and the airspace above FL600.

Class G —That airspace not designated as Class A, B, C, D, or E. Class G airspace is essentially uncontrolled by ATC except when associated with a temporary control tower.

Special Use Airspace

Special use airspace is the designation for airspace in which certain activities must be confined, or where limitations may be imposed on aircraft operations that are not part of those activities. Certain special use airspace areas can create limitations on the mixed use of airspace. The special use airspace depicted on instrument charts includes the area name or number, effective altitude, time and weather conditions of operation, the controlling agency, and the chart panel location. On National Aeronautical Charting Office (NACO) en route charts, this information is available on the panel opposite the air/ground (A/G) voice communications.

Instrument approach procedures Special use airspace: Airspace in (IAPs): A series of predetermined which certain activities are subject to maneuvers for the orderly transfer of restrictions that can create limitations an aircraft under IFR from the on the mixed use of airspace. Consists beginning of the initial approach to a of prohibited, restricted, warning, landing or to a point from which a military operations, and alert areas. landing may be made visually.

Prohibited areas contain airspace of defined dimensions within which the flight of aircraft is prohibited. Such areas are established for security or other reasons associated with the national welfare. These areas are published in the Federal Register and are depicted on aeronautical charts. The area is charted as a “P” with a number (e.g., “P-123”). As the name implies, flight through this airspace is not permitted.

Restricted areas are areas where operations are hazardous to nonparticipating aircraft and contain airspace within which the flight of aircraft, while not wholly prohibited, is subject to restrictions. Activities within these areas must be confined because of their nature, or limitations imposed upon aircraft operations that are not a part of those activities, or both. Restricted areas denote the existence of unusual, often invisible, hazards to aircraft (e.g., artillery firing, aerial gunnery, or guided missiles). IFR flights may be authorized to transit the airspace and are routed accordingly. Penetration of restricted areas without authorization from the using or controlling agency may be extremely hazardous to the aircraft and its occupants. ATC facilities apply the following procedures when aircraft are operating on an IFR clearance (including those cleared by ATC to maintain visual flight rules (VFR)-On-Top) via a route that lies within joint-use restricted airspace:

1. If the restricted area is not active and has been released to the Federal Aviation Administration (FAA), the ATC facility will allow the aircraft to operate in the restricted airspace without issuing specific clearance for it to do so.
2. If the restricted area is active and has not been released to the FAA, the ATC facility will issue a clearance which will ensure the aircraft avoids the restricted airspace.

Restricted areas are charted with an “R” followed by a number (e.g., “R-5701”) and are depicted on the en route chart appropriate for use at the altitude or FL being flown.

Warning areas are similar in nature to restricted areas; however, the U.S. government does not have sole jurisdiction over the airspace. A warning area is airspace of defined dimensions, extending from 3 NM outward from the coast of the U.S., containing activity that may be hazardous to nonparticipating aircraft. The purpose of such areas is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic or international waters or both. The airspace is designated with a “W” and a number (e.g., “W-123”).

aids; they are depicted in blue on

aeronautical charts.

pertinent to IFR flight.

Tower En Route Control (TEC) is an ATC program that uses overlapping approach control radar services to provide IFR clearances. By using TEC, you are routed by airport control towers. Some advantages include abbreviated filing procedures, fewer delays, and reduced traffic separation requirements. TEC is dependent upon the ATC’s workload and the procedure varies among locales.

Tower En Route Control (TEC): The control of IFR en route traffic within delegated airspace between two or more adjacent approach control facilities, designed to expedite traffic and reduce control and pilot communication requirements.

The latest version of Advisory Circular (AC) 90-91, National Route Program, provides guidance to users of the NAS for participation in the National Route Program (NRP). All flights operating at or above FL290 within the conterminous

U.S. are eligible to participate in the NRP, the primary purpose of which is to allow operators to plan minimum time/ cost routes that may be off the prescribed route structure.

National Route Program (NRP):

A set of rules and procedures designed to increase the flexibility of user flight planning within published guidelines.

En route high-altitude charts: IFR en route low-altitude charts:

Aeronautical charts for en route Aeronautical charts for en route IFR instrument navigation at or above navigation in the low-altitude 18,000 feet MSL. stratum.

Area navigation (RNAV) routes, including routes using global positioning system (GPS) for navigation, are not normally depicted on IFR en route charts. However, a number of RNAV routes have been established in the high-altitude structure and are depicted on the RNAV en route high altitude charts. RNAV instrument departure procedures (DPs) and standard terminal arrival routes (STARs) are contained in the U.S. Terminal Procedures booklets. The Graphic Notices and Supplemental Data also contains a tabulation of RNAV routes.

In addition to the published routes, you may fly a random RNAV route under IFR if it is approved by ATC. Random RNAV routes are direct routes, based on area navigation capability, between waypoints defined in terms of latitude/ longitude coordinates, degree-distance fixes, or offsets from established routes/airways at a specified distance and direction.

Radar monitoring by ATC is required on all random RNAV routes. These routes can only be approved in a radar environment. Factors that will be considered by ATC in approving random RNAV routes include the capability to provide radar monitoring, and compatibility with traffic volume and flow. ATC will radar monitor each flight; however, navigation on the random RNAV route is the responsibility of the pilot.

Reliance on RNAV systems for instrument approach operations is becoming more commonplace as new systems, such as GPS and wide area augmentation system (WAAS) are developed and deployed. In order to foster and support full integration of RNAV into the NAS, the FAA has developed a charting format for RNAV approach charts.

Airport Information

Airport information is provided in the legend, and the symbols used for the airport name, elevation, and runway length are similar to the sectional chart presentation. Instrument approaches can be found at airports with blue or green symbols, while the brown airport symbol denotes airports that do not have approved instrument approaches. Asterisks are used to indicate the part-time nature of tower operations, lighting facilities, and airspace classifications (consult the communications panel on the chart for primary radio frequencies and hours of operation). The asterisk could also indicate that approaches are not permitted during the

Area chart: Part of the low-altitude en route chart series, these charts furnish terminal data at a larger scale in congested areas.

nonoperating hours, and/or filing as an alternate is not approved during specified hours. A box after an airport name with a “C” or “D” inside indicates Class C and D air

space, respectively.

[figure 8-3]

Charted IFR Altitudes

The minimum en route altitude (MEA) ensures a navigation signal strong enough for adequate reception by the aircraft navigation (NAV) receiver and adequate obstacle clearance along the airway. Communication is not necessarily guaranteed with MEA compliance. The obstacle clearance, within the limits of the airway, is typically 1,000 feet in nonmountainous areas and 2,000 feet in designated mountainous areas. MEAs can be authorized with breaks in the signal coverage; if this is the case, the NACO en route chart notes “MEA GAP” parallel to the affected airway. MEAs are usually bidirectional; however, they can be unidirectional. Arrows are used to indicate the direction to which the MEA applies.

The minimum obstruction clearance altitude (MOCA), as the name suggests, provides the same obstruction clearance as an MEA; however, the NAV signal reception is only ensured within 22 NM of the closest NAVAID defining the route. The MOCA is listed below the MEA and indicated on NACO charts by a leading asterisk (e.g., “*3400”—see figure 8-2, V287 at bottom left in figure).

Minimum en route altitude Minimum obstruction clearance Minimum reception altitude Maximum authorized altitude (MEA): The lowest published altitude (MOCA): The lowest (MRA): The lowest altitude at (MAA): A published altitude altitude between radio fixes which published altitude in effect between which an airway intersection can representing the maximum usable ensures acceptable navigational radio fixes on VOR airways, off-be determined. altitude or FL for an airspace signal coverage and meets obstacle airway routes, or route segments structure or route segment.

clearance requirements between which meets obstacle clearance (MCA): The lowest altitude atthose fixes. requirements for the entire route certain fixes at which an aircraftsegment and which ensures must cross when proceeding in theacceptable navigational signal direction of a higher MEA.

coverage only within 25 statute (22 nautical) miles of a VOR.

When an MEA, MOCA, and/or MAA change on a segment

other than a NAVAID, a sideways “T”

is depicted on the chart. If there is an airway break without the symbol, you can assume the altitudes have not changed (see the upper left area of figure 8-2). When a change of MEA to a higher MEA is required, the climb may commence at the break, ensuring obstacle clearance. [figure 8-4B]

Navigation Features

Types of NAVAIDs

Very-high frequency omnidirectional ranges (VORs) are the principal NAVAIDs that support the Victor airways. Many other navigation tools are also available to the pilot. For example, nondirectional beacons (NDBs) can broadcast signals accurate enough to provide stand-alone approaches, and DME allows the pilot to pinpoint a reporting point on the airway. Though primarily navigation tools, these NAVAIDs can also transmit voice broadcasts.

Tactical air navigation (TACAN) channels are represented as the two- or three-digit numbers following the three-letter identifier in the NAVAID boxes. The NACO terminal procedures provide a frequency-pairing table for the TACAN-only sites. On NACO charts, very-high frequencies and ultra-high frequencies (VHF/UHF) NAVAIDs (e.g., VORs) are depicted in black, while low frequencies and medium frequencies (LF/MF) are depicted as brown. [figure 8-4A]

Identifying Intersections

Intersections along the airway route are established by a

variety of NAVAIDs. An open triangle

indicates the

location of an ATC reporting point at an intersection; if the triangle is solid,

a report is compulsory. [figure 8-4B] NDBs, localizers, and off-route VORs are used to establish intersections. NDBs are sometimes colocated with intersections, in which case passage of the NDB would mark the intersection. A bearing to an off-route NDB also can provide intersection identification. The presence of a localizer course can be determined from a feathered arrowhead symbol on the en route chart.

If crosshatched markings appear on the left-hand side of the arrowhead, a

back course (BC) signal is transmitted. On NACO charts, the localizer symbol is depicted to identify an intersection.

Back course (BC): The reciprocal of the localizer course for an ILS. When flying a back-course approach, an aircraft approaches the instrument runway from the end on which the localizer antennas are installed.

When you travel on an airway, off-route VORs remain the most common means of identifying intersections. Arrows

depicted next to the intersection

to be used for identification. Another means of identifying an intersection is with the use of DME. A hollow arrowhead

indicates DME is authorized for intersection identification. If the DME mileage at the intersection is a cumulative distance of route segments, the mileage is totaled and indicated by a D-shaped symbol with a number inside. Typically, the distance numbers do not appear on the initial segment. [figure 8-4B, Route Data] Approved IFR GPS units can also be used to report intersections if the intersection name resides in a current database.

Other Route Information

DME and GPS provide valuable route information concerning such factors as mileage, position, and groundspeed. Even without this equipment, information is provided on the charts for making the necessary calculations using time and distance. The en route chart depicts point-to-point distances on the airway system. Distances from VOR to VOR are

charted with a number inside of a box.

tiate distances when two airways cross, the word “TO” with the three-letter VOR identifier appears next to the distance box.

VOR changeover points (COPs) are depicted on the charts by this symbol:

The numbers indicate the distance at which to change the VOR frequency. The frequency change might be required due to signal reception or conflicting frequencies. If a COP does not appear on an airway, the frequency should be changed midway between the facilities. A COP at an intersection often indicates a course change.

Occasionally an “x” will appear at a separated segment of an airway that is not an intersection. The “x” is a mileage breakdown or computer navigation fix and indicates a course change.

Changeover points (COPs): A point Mileage breakdown or computer along the route where changeover in navigation fix: A fix indicating a navigation guidance should occur. course change that appears on the

figure 8-4A. Legend from en route low altitude chart. (Air Traffic Services and Airspace Information section of the legend is continued on the next page.)

figure 8-4B. Legend from en route low altitude chart (continued).

Today’s computerized system of ATC has greatly reduced the need for holding en route. However, published holding patterns are still found on charts at junctures where ATC has deemed it necessary to enable traffic flow. When a holding pattern is charted, the controller may provide the holding direction and the statement “as published.” [figure 8-4B]

Boundaries separating the jurisdiction of Air Route Traffic Control Centers (ARTCC) are depicted on charts with blue serrations.

The name of the controlling facility is printed on the corresponding side of the division line. ARTCC remote sites are depicted as blue serrated boxes and contain the center name, sector name, and the sector frequency. [figure 8-4B]

Weather Information and Communication Features

En route NAVAIDs also provide weather information and serve communication functions. When a NAVAID is shown as a shadowed box, an automated flight service station (AFSS) of the same name is directly associated with the facility. If an AFSS is located without an associated NAVAID, the shadowed box is smaller and contains only the name and identifier. The AFSS frequencies are provided on top of the box. (Frequency 122.2 and the emergency frequency 121.5 are not listed.)

A Remote Communications Outlet (RCO) associated with a NAVAID is designated by a fine-lined box with the controlling AFSS frequency on the top, and the name under the box, respectively. Without an associated facility, the fine-lined RCO box contains the AFSS name and remote frequency.

Hazardous Inflight Weather Advisory Service (HIWAS) and Transcribed Weather Broadcast (TWEB) are continuously transmitted over selected NAVAIDs and depicted in the NAVAID

Air Route Traffic Control Center Hazardous Inflight Weather (ARTCC): Established to provide Advisory Service (HIWAS): ATC service to aircraft operating on Recorded weather forecasts IFR flight plans within controlled broadcast to airborne pilots over airspace and principally during the en selected VORs. route phase of flight.

Transcribed Weather Broadcast Remote Communications Outlet (TWEB): Meteorological and (RCO): An unmanned communica-aeronautical data is recorded on tions facility remotely controlled by tapes and broadcast over selected air traffic personnel. NAVAIDs.

Instrument Approach Procedures Charts (IAPs)

Standard terminal arrival route (STAR): Preplanned IFR ATC arrival procedures, published for pilot use in textual and graphic format.

Margin Identification

The margin identification, at the top and bottom of the chart, depicts the airport location and procedure identification. The approach plates are organized by city first, then airport name and state. For example, Spokane International in Spokane, Washington is alphabetically listed under “S” for Spokane.

The chart’s amendment status appears above the procedure identification in the top margin (and below in the bottom margin), along with the volume’s effective date. (The five-digit date format in the amendment, “00167” is read, “the 167th day of 2000.”) At the center of the top margin is the FAA chart reference number and approving authority and, at the bottom center, the airport’s latitude and longitude coordinates.

The procedure identification (top and bottom margin area of figure 8-7) is derived from the type of navigational facility providing final approach course guidance. A runway number is listed when the approach course is aligned within 30° of the runway centerline (e.g., “ILS RWY 19” or “VOR RWY 29”); this type of approach allows a straight-in landing under the right conditions. Some airports have parallel runways and simultaneous approach procedures. To distinguish between the left, right, and center runways, an “L,” “R,” or “C” follows the runway number (e.g., “ILS RWY 16R”). If the approach course diverges more than 30° from the runway centerline, a letter from the beginning of the alphabet is assigned (e.g., “VOR-A”). The letter designation signifies the expectation is for the procedure to culminate in a circling approach to land. In some cases, an airport might have more than one circling approach.

The navigational system required for the final approach segment can be determined by the procedure identification (top and bottom margin area of figure 8-7). The identification is derived from the type of navigational facility providing the final approach course guidance for straight-in approaches and the runway to which the course is aligned (e.g., ILS RWY 19 or RNAV RWY 29). Some airports have parallel runways and simultaneous approach procedures. To distinguish between the left, right, and center runways, an “L,” “R,” or “C” follows the runway number (e.g., NDB RWY 16R). For approaches that do not meet straight-in criteria, a letter from the beginning of the alphabet is assigned (e.g., VOR-A or LDA-B). The letter designation signifies the expectation is

Margin identification: The top and Amendment status: The circulation bottom areas on an instrument date and revision number of an approach chart that depict instrument approach procedure, information about the procedure printed above the procedure including airport location and identification. procedure identification.

Plan view: Overhead view of an Reference circle (also, distance

approach procedure on an IAP chart. circle): The circle depicted in the

Dashed circles, or concentric rings around the distance circle, are used when the information necessary to the procedure will not fit to scale within the limits of the plan view area. They serve as a means to systematically arrange this information in its relative position outside and beyond the reference circle. These concentric rings are labeled en route facilities and feeder facilities. The en route facilities ring depicts NAVAIDs, fixes, and intersections that are part of the en route low altitude airway structure used in the approach procedure. The feeder facilities ring includes radio aids to navigation, fixes and intersections used by ATC to direct aircraft to intervening facilities/fixes between the en route structure and the IAF. Feeder routes are not part of the en route structure.

The primary airport depicted in the plan view is drawn with enough detail to show the runway orientation and final approach course alignment. Airports other than the primary approach airport are not depicted in the NACO plan view.

Known spot elevations and obstacles are indicated on the plan view in MSL altitudes. The largest dot and number combination indicates the highest elevation. An inverted “V”

with a dot in the center depicts an obstacle.

1. The highest obstacle is indicated with a bolder, larger version of the same symbol. Two interlocking inverted V’s
2. signify a group of obstacles. [figure 8-8]

In the top left or right corner of the plan view is the communications area. Communication frequencies are generally listed in the order in which they would be used during arrival. Frequencies for weather and related facilities are included, where applicable, such as automatic terminal information service (ATIS), automated surface observing system (ASOS), automated weather observing system (AWOS) and AFSS’s.

Concentric rings: The dashed-line En route facilities ring: A circle circles depicted in the plan view of depicted in the plan view of IAP IAP charts, outside of the reference charts, which designates NAVAIDs, circle, that show en route and feeder fixes, and intersections that are part facilities. of the en route low altitude airway

Feeder facilities: NAVAIDs used by ATC to direct aircraft to intervening fixes between the en route structure and the initial approach fix.

The minimum safe altitude (MSA) circle appears in the plan view, except in approaches for which appropriate NAVAIDs (e.g., VOR or NDB) are unavailable. The MSA is provided for emergency purposes only and guarantees 1,000 feet obstruction clearance in the sector indicated with reference to the bearing in the circle. For conventional navigation systems, the MSA is normally based on the primary omnidirectional facility on which the IAP is predicated. The MSA depiction on the approach chart contains the facility identifier of the NAVAID used to determine the MSA altitudes. For RNAV approaches, the MSA is based on the runway waypoint for straight-in approaches, or the airport waypoint for circling approaches. For GPS approaches, the MSA center will be the missed approach waypoint. The MSL altitudes appear in boxes within the circle, which is typically a 25 NM radius unless otherwise indicated. The MSA circle refers to the letter identifier of the NAVAID or waypoint that describes the center of the circle. MSAs are not depicted on terminal arrival area (TAA) approach charts.

NAVAIDs, included in the plan view, are necessary for the completion of the instrument procedure and include the facility name, frequency, letter identifier, and Morse code sequence. A heavy-lined NAVAID box depicts the primary NAVAID used for the approach. An “I” in front of the NAVAID identifier (in figure 8-7, “I-OLJ”) listed in the NAVAID box indicates a localizer and a TACAN channel (which signifies DME availability). The requirement for an ADF, DME or RADAR in the approach is noted in the plan view.

Intersections, fixes, radials, and course lines describe route and approach sequencing information. The main procedure, or final approach course is a thick, solid line. A DME arc, which is part of the main procedure course, is also represented as a thick, solid line. A feeder route

is depicted with a medium line and provides heading, altitude, and distance information. (All three components must be designated on the chart to provide a navigable course.) Radials, such as lead radials, are shown by thin lines. The missed approach track is drawn

using a thin dashed line with a directional

arrow. A visual flight path segment appears as a thick

Minimum safe altitude (MSA):

The minimum altitude depicted on approach charts which provides at least 1,000 feet of obstacle clearance for emergency use within a specified distance from the listed navigation facility or waypoint.

dashed line with a directional arrow.

Initial approach fixes (IAFs) are charted IAF when associated with a NAVAID or when freestanding.

The missed approach holding pattern track is represented with a thin-dashed line. When colocated, the missed approach holding pattern and procedure turn holding pattern are indicated as a solid, black line. Arrival holding patterns are depicted as thin, solid lines.

Course Reversal Elements in Plan View and Profile View

Course reversals are included in an IAP, are depicted in one of three different ways, a 45°/180° procedure, a holding pattern, or a teardrop procedure. The maneuvers are required when it is necessary to reverse direction to establish the aircraft inbound on an intermediate or final approach course. Components of the required procedure are depicted in the plan view and the profile view. The maneuver must be completed within the distance and at the minimum altitude specified in the profile view. Pilots should coordinate with the appropriate ATC facility relating to course reversal during the IAP.

Procedure Turns

A procedure turn barbed arrow

tion or side of the outbound course on which the procedure turn is made. Headings are provided for course reversal using the 45° procedure turn. However, the point at which the turn may be commenced, and the type and rate of turn is left to the discretion of the pilot. Some of the options are the 45° procedure turn, the racetrack pattern, the teardrop procedure turn, or the 80°/260° course reversal. The absence of the procedure turn barbed arrow in the plan view indicates that a procedure turn is not authorized for that procedure. A maximum procedure turn speed of not greater than 200 knots indicated airspeed (KIAS) should be observed when turning outbound over the IAF and throughout the procedure turn maneuver to ensure staying within the obstruction clearance area. The normal procedure turn distance is 10 NM. This may be reduced to a minimum of 5 NM where only Category A or helicopter aircraft are operated, or increased to as much as 15 NM to accommodate high performance aircraft. Descent below the procedure turn altitude begins after the aircraft is established on the inbound course.

Initial approach fix (IAF): The Procedure turn: The maneuver fixes depicted on IAP charts that prescribed when it is necessary to identify the beginning of the initial reverse direction to establish an approach segment(s). aircraft on the intermediate approach

The procedure turn is not required when the symbol “NoPT” appears, when radar vectoring to the final approach is provided, when conducting a timed approach, or when the procedure turn is not authorized. Pilots should contact the appropriate ATC facility when in doubt if a procedure turn is required.

A holding pattern in lieu of a procedure turn may be specified for course reversal in some procedures. In such cases, the holding pattern is established over an intermediate fix or a final approach fix (FAF). The holding pattern distance or time specified in the profile view must be observed. Maximum holding airspeed limitations as set forth for all holding patterns apply. The holding pattern maneuver is completed when the aircraft is established on the inbound course after executing the appropriate entry. If cleared for the approach prior to returning to the holding fix, and the aircraft is at the prescribed altitude, additional circuits of the holding pattern are not necessary nor expected by ATC. If pilots elect to make additional circuits to lose excessive altitude or to become better established on course, it is their responsibility to advise ATC upon receipt of their approach clearance. When holding in lieu of a procedure turn, the holding pattern must be followed, except when RADAR VECTORING to the final approach course is provided or when NoPT is shown on the approach course.

When a teardrop procedure turn is depicted and a course reversal is required, unless otherwise authorized by ATC, this type of procedure must be executed. The teardrop procedure consists of departure from an IAF on the published outbound course followed by a turn toward and intercepting the inbound course at or prior to the intermediate fix or point. Its purpose is to permit an aircraft to reverse direction and lose considerable altitude within reasonably limited airspace. Where no fix is available to mark the beginning of the intermediate segment, it shall be assumed to commence at a point 10 NM prior to the FAF. When the facility is located on the airport, an aircraft is considered to be on final approach upon completion of the penetration turn. However, the final approach segment begins on the final approach course 10 NM from the facility.

NoPT (No Procedure Turn): Used Final approach fix (FAF): The fix with the appropriate course and from which the IFR final approach to altitude to denote the procedure turn an airport is executed, which is not required. identifies the beginning of the final

The Profile View

The profile view is a drawing of the side view of the procedure and illustrates the vertical approach path altitudes, headings, distances, and fixes. [figure 8-7] The view includes the minimum altitude and maximum distance for the procedure turn, altitudes over prescribed fixes, distances between fixes, and the missed approach procedure. The profile view aids in the pilot’s interpretation of the IAP. The profile view is not drawn to scale. [Figures 8-10 and 8-11]

The precision approach glide-slope intercept altitude is a minimum altitude for glide slope interception after completion of the procedure turn, illustrated by an altitude

number and “zigzag” line.

It applies to precision approaches, and except where otherwise prescribed, also applies as a minimum altitude for crossing the FAF when the glide slope is inoperative or not used. Precision approach

Profile view: Side view of an approach procedure on an IAP chart illustrating the vertical approach path altitudes, headings, distances, and fixes.

Glide-slope intercept altitude: The minimum altitude of an intermediate approach segment prescribed for a precision approach that ensures obstacle clearance.

profiles also depict the glide-slope angle of descent, threshold-crossing height (TCH), and glide-slope altitude at the outer marker (OM).

In nonprecision approaches, a final descent is initiated at the FAF, or after completing the procedure turn and established inbound on the procedure course. The FAF is clearly identified by use of the Maltese cross symbol in the profile view.

When the FAF is not indicated in the profile view, the MAP is based on station passage when the facility is on the airport or a specified distance (e.g., VOR/DME or GPS procedures).

Stepdown fixes in nonprecision procedures are provided between the FAF and the airport for authorizing a lower minimum descent altitude (MDA) after passing an obstruction. Stepdown fixes can be identified by NAVAID, NAVAID fix, waypoint, radar, and are depicted by a vertical

dashed line.

Normally, there is only one stepdown fix between the FAF and the MAP, but there can be several. If the stepdown fix cannot be identified for any reason, the minimum altitude at the stepdown fix becomes the MDA for the approach. However, circling minimums apply if they are higher than the stepdown fix minimum altitude, and a circling approach is required.

The visual descent point (VDP) is a defined point on the final approach course of a nonprecision straight-in approach procedure. A normal descent from the MDA to the runway touchdown point may be commenced, provided visual reference is established. The VDP is identified on the profile view of the approach chart by the symbol “V.” [figure 8-11]

The missed approach point (MAP) varies depending upon the approach flown. For the ILS, the MAP is at the decision altitude/decision height (DA/DH). In nonprecision procedures, the pilot determines the MAP by timing from FAF when the approach aid is well away from the airport, by a fix or NAVAID when the navigation facility is located on the field, or by waypoints as defined by GPS or VOR/DME RNAV. The pilot may execute the MAP early, but pilots should, unless otherwise cleared by ATC, fly the IAP as specified on the approach plate to the MAP at or above the MDA or DA/DH before executing a turning maneuver.

Visual descent point (VDP): A defined point on the final approach course of a nonprecision straight-in approach procedure from which normal descent from the MDA to the runway touchdown point may be commenced, provided the runway environment is clearly visible to the pilot.

A complete description of the missed approach procedure appears in the profile view. [figure 8-11] When initiating a missed approach, the pilot will be directed to climb straight ahead (e.g., “Climb to 2,500”), or commence a turning climb to a specified altitude (e.g., “Climbing left turn to 2,500”). In some cases, the procedure will direct the pilot to climb straight ahead to an initial altitude, then turn or enter a climbing turn to the holding altitude (e.g., “Climb to 900, then climbing right turn to 2,500 direct ABC VOR and hold”).

When the missed approach procedure specifies holding at a facility or fix, the pilot proceeds according to the missed approach track and pattern depicted on the plan view. An alternate missed approach procedure may also be issued by ATC. The textual description will also specify the NAVAID(s) or radials that identify the holding fix.

The profile view also depicts minimum, maximum, recommended, and mandatory block altitudes used in approaches. The minimum altitude is depicted with the

On final approach, aircraft are

required to maintain an altitude at or above the depicted altitude until reaching the subsequent fix. The maximum

and aircraft must remain at or below the depicted altitude. Mandatory altitude will be depicted with the altitude both

and altitude is to be

maintained at the depicted value. Recommended altitudes are advisory altitudes and are neither over- nor underscored. When an over- or underscore spans two numbers, a mandatory block altitude is indicated, and aircraft are required to maintain altitude within the range of the two numbers. [Figures 8-10 and 8-11]

The minimums section sets forth the lowest altitude and visibility requirements for the approach, whether precision or nonprecision, straight-in or circling, or radar vectored. When a fix is incorporated in a nonprecision final segment,

Missed approach procedure: A Aircraft approach category: A maneuver performed by a pilot when performance grouping of aircraft an instrument approach cannot be based on a speed of 1.3 times their completed to a landing. stall speed in the landing

IAP chart that displays the lowest altitude and visibility requirements Decision altitude (DA): A specified for the approach. altitude in the precision approach,

missed approach must be initiated if

continue the approach has not been

CATEGORY	A	B	C	D
GLS PA DA	1382/24 200 (200-1⁄2)
LNAV/DA VNAV	318 (400-1⁄2)1500/24			1500/40318 (400-34⁄ )
LNAV MDA	1700/24 518 (600-1⁄2)		1700/50 518 (600-1)	1700/60 518 (600-114⁄ )
CIRCLING	1760-1 578 (600-1)		1760-11⁄2 578 (600-11⁄2)	1760-2 578 (600-2)

figure 8-13. Aircraft approach categories and circling limits.

figure 8-14. RVR conversion table.

Visibility figures are provided in statute miles or runway visual range (RVR), which is reported in hundreds of feet. RVR is measured by a transmissometer, which represents the horizontal distance measured at points along the runway. It is based on the sighting of either high intensity runway lights or on the visual contrast of other targets, whichever yields the greater visual range. RVR is horizontal visual range, not slant visual range, and is used in lieu of prevailing visibility in determining minimums for a particular runway. [figure 8-14]

Visibility figures are depicted after the DA/DH or MDA in the minimums section. If visibility in statute miles is indicated, an altitude number, hyphen, and a whole or fractional number appear; for example, 530-1, which indicates “530 feet MSL” and 1 statute mile visibility, this is the descent minimum for the approach. The RVR value is separated from the minimum altitude with a slash, such as

Runway visual range (RVR): The instrumentally-derived horizontal distance a pilot should be able to see down the runway from the approach end, based on either the sighting of high-intensity runway lights, or the visual contrast of other objects.

8–24

“1065/24,” which indicates 1,065 feet MSL and an RVR of 2,400 feet. If RVR were prescribed for the procedure, but not available, a conversion table would be used to provide the equivalent visibility — in this case, of 1/2 statute mile visibility. [figure 8-14] The conversion table is also available in the TPP.

When an alternate airport is required, standard IFR alternate minimums apply. Precision approach procedures require a 600-foot ceiling and 2 statute miles visibility; nonprecision approaches require an 800-foot ceiling and 2 statute miles visibility. When a black triangle with a white “A” appears in the Notes section of the approach chart, it indicates nonstandard IFR alternate minimums exist for the airport. If an

alternate minimums are not authorized. This information is found in the beginning of the TPP.

Procedural notes are included in a box located below the altitude and visibility minimums. For example, a procedural note might indicate, “Circling NA E of RWY 1-19.” Some other notes might concern a local altimeter setting and the resulting change in the minimums. The use of RADAR may also be noted in this section. Additional notes may be found in the plan view.

appears in the notes area, it signifies the airport has nonstandard IFR takeoff minimums. The appropriate section in the front of the TPP would be consulted in this case.

In addition to the COPTER approaches, instrument-equipped helicopters may fly standard approach procedures. The required visibility minimum may be reduced to one-half the published visibility minimum for category A aircraft, but in no case may it be reduced to less than 1/4 mile or 1,200 feet RVR.

Alternate airport: Designated in an Point in space approach: A type of IFR flight plan, provides a suitable helicopter instrument approach destination if a landing at the intended procedure to a missed approach point airport becomes inadvisable. more than 2,600 feet from an

associated helicopter landing area.

HAL is a height above a designated Airport diagram: The section of an helicopter landing area used for IAP chart that shows a detailed helicopter instrument approach diagram of the airport including procedures. surface features and airport

Inoperative Components

Certain procedures can be flown with inoperative components. According to the Inoperative Components Table, for example, an ILS approach with a malfunctioning Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights (MALSR = MALS with RAIL) can be flown if the minimum visibility is increased by 1/4 mile. [figure 8-17] A note in this section might read, “Inoperative Table does not apply to ALS or HIRL Runway 13L.”

RNAV Instrument Approach Charts

Instrument approach charts are being converted to a charting format similar to the format developed for RNAV IAP. [figure 8-18] This format avoids unnecessary duplication and proliferation of instrument approach charts. The approach minimums for unaugmented GPS, Wide Area Augmentation System (WAAS), Local Area Augmentation System (LAAS), will be published on the same approach chart as lateral navigation/vertical navigation (LNAV/VNAV). Other types of equipment may be authorized to conduct the approach based on the minima notes in the front of the TPP approach chart books. Approach charts titled “RNAV RWY XX” may be used by aircraft with navigation systems that meet the required navigational performance (RNP) values for each segment of the approach.

The chart may contain as many as four lines of approach minimums: Global landing system (GLS); WAAS and LAAS; LNAV/VNAV; LNAV; and circling. LNAV/VNAV is an instrument approach with lateral and vertical guidance with integrity limits similar to barometric vertical navigation (BARO VNAV).

RNAV procedures that incorporate a final approach stepdown fix may be published without vertical navigation, on a separate chart, also titled RNAV. During a transition period when GPS procedures are undergoing revision to a new title, both RNAV and GPS approach charts and formats will be published. ATC clearance for the RNAV procedure will authorize a properly-certificated pilot to utilize any landing minimums for which the aircraft is certified.

The RNAV chart will include formatted information required for quick pilot or flightcrew reference located at the top of the chart. This portion of the chart was developed based on a

Inoperative components: Higher Required navigational minimums are prescribed when the performance (RNP): Navigational specified visual aids are not performance necessary to operate in functioning; this information is listed a given airspace or perform a in the Inoperative Components Table particular procedure. found in the Terminal Procedures Publications.

study by the Department of Transportation (DOT), Volpe National Transportation Systems Center.

Chart terminology will change slightly to support the new procedure types:

1. DA replaces the term DH. DA conforms to the international convention where altitudes relate to MSL and heights relate to AGL. DA will eventually be published for other types of IAPs with vertical guidance, as well. DA indicates to the pilot that the published descent profile is flown to the DA (MSL), where a missed approach will be initiated if visual references for landing are not established. Obstacle clearance is provided to allow a momentary descent below DA while transitioning from the final approach to the missed approach. The aircraft is expected to follow the missed approach instructions while continuing along the published final approach course to at least the published runway threshold waypoint or MAP (if not at the threshold) before executing any turns.
2. MDA will continue to be used for the LNAV-only and circling procedures.
3. Threshold crossing height (TCH) has been traditionally used in precision approaches as the height of the glide slope above threshold. With publication of LNAV/VNAV minimums and RNAV descent angles, including graphically depicted descent profiles, TCH also applies to the height of the “descent angle,” or glidepath, at the threshold. Unless otherwise required for larger type aircraft which may be using the IAP, the typical TCH will be 30 to 50 feet.

The minima format changes slightly:

1. Each line of minima on the RNAV IAP will be titled to reflect the RNAV system applicable (e.g., GLS, LNAV/ VNAV, and LNAV.) Circling minima will also be provided.
2. The minima title box will also indicate the nature of the minimum altitude for the IAP. For example: DA will be published next to the minima line title for minimums supporting vertical guidance, and MDA will be published where the minima line supports only lateral guidance. During an approach where an MDA is used, descent below MDA is not authorized.

Global Landing System (GLS): Barometric vertical navigation Global Navigation Satellite System (BARO VNAV): A navigational (GNSS) that includes WAAS and/or system which presents computed LAAS. vertical guidance to the pilot

3. Where two or more systems share the same minima, each For more information concerning government charts, the line of minima will be displayed separately. NACO can be contacted by telephone, or via their internet address at:

The following chart symbology will change slightly: [Figure

8-18] National Aeronautical Charting Office