Instrument Approach Procedure Charts

The instrument approach procedure (IAP) chart provides the method to descend and land safely in low visibility conditions. The FAA establishes an IAP after thorough analyses of obstructions, terrain features, and navigational facilities. Maneuvers, including altitude changes, course corrections, and other limitations, are prescribed in the IAP. The approach charts reflect the criteria associated with the United States Standard for Terminal Instrument Approach Procedures (TERPs), which prescribes standardized methods for use in designing instrument flight procedures.

In addition to the AeroNav Products, other governmental and corporate entities produce approach procedures. The U.S. Military IAPs are established and published by the Department of Defense and are available to the public upon request. Special IAPs are approved by the FAA for individual operators and are not available to the general public. Foreign country standard IAPs are established and published according to the individual country’s publication procedures. The information presented in the following sections highlight features of the United States TPP.

The National Airspace System
Figure 1. Instrument approach chart

The instrument approach chart is divided into six main sections, which include the margin identification, pilot briefing (and notes), plan view, profile view, landing minimums, and airport diagram. [Figure 1] An examination of each section follows.

Margin Identification

The margin identification, at the top and bottom of the chart, depicts the airport location and procedure identification. The civil approach plates are organized by city, then airport name and state. For example, Orlando Executive in Orlando, Florida, is alphabetically listed under “O” for Orlando. Military approaches are organized by airport name first.

The chart’s amendment status appears below the city and state in the bottom margin. The amendment number is followed by the five-digit julian-date of the last chart change.“05300” is read, “the 300th day of 2005.” At the center of the top margin is the FAA chart reference number and the approving authority. At the bottom center, the airport’s latitude and longitude coordinates are provided. If a chart is original, the date of issuance can be used instead of the julian-date.

The procedure chart title (top and bottom margin area of Figure 1) 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 30º of the runway centerline. This type of approach allows a straight-in landing under the right conditions. The type of approach followed by a letter identifies approaches that do not have straight-in landing minimums. Examples include procedure titles at the same airport, which have only circling minimums. The first approach of this type created at the airport is labeled with the letter A, and the lettering continues in alphabetical order (e.g., “VOR-A or “LDA-B”). The letter designation signifies the expectation is for the procedure to culminate in a circling approach to land. As a general rule, circling-only approaches are designed for one of the two following reasons:
  • The final approach course alignment with the runway centerline exceeds 30º.
  • The descent gradient is greater than 400 FPNM from the final approach fix (FAF) to the threshold crossing height (TCH). When this maximum gradient is exceeded, the circling-only approach procedure may be designed to meet the gradient criteria limits.

Further information on this topic can be found in the Instrument Procedures Handbook, Chapter 4, under Approach Naming Chart Conventions.

To distinguish between the left, right, and center runways, an “L,” “R,” or “C” follows the runway number (e.g., “ILS RWY 16R”). In some cases, an airport might have more than one circling approach, shown as VOR-A, VOR/DME-B, etc.

More than one navigational system separated by a slash indicates more than one type of equipment is required to execute the final approach (e.g., VOR/DME RWY 31). More than one navigational system separated by “or” indicates either type of equipment may be used to execute the final approach (e.g., VOR or GPS RWY 15). Multiple approaches of the same type, to the same runway and using the same guidance, have an additional letter from the end of the alphabet, number, or term in the title (e.g., ILS Z RWY 28, SILVER ILS RWY 28, or ILS 2 RWY 28). VOR/DME RNAV approaches are identified as VOR/DME RNAV RWY (runway number). Helicopters have special IAPs designated with COPTER in the procedure identification (e.g., COPTER LOC/DME 25L). Other types of navigation systems may be required to execute other portions of the approach prior to intercepting the final approach segment or during the missed approach.

The Pilot Briefing

The pilot briefing is located at the top of the chart and provides the pilot with information required to complete the published approach procedure. Included in the pilot briefing are the NAVAID providing approach guidance, its frequency, the final approach course, and runway information. A notes section contains additional procedural information. For example, a procedural note might indicate restrictions for circling maneuvers. 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.

When a triangle containing a “T” (see Image - a) appears in the notes section, it signifies the airport has nonstandard IFR takeoff minimums. Pilots should refer to the DPs section of the TPP to determine takeoff minimums.

Instrument Approach Procedure Charts
Image - a

When a triangle containing an “A” (see Image - b) appears in the notes section, it signifies the airport has nonstandard IFR alternate minimums. Civil pilots should refer to the Alternate Minimums Section of the TPP to determine alternate minimums. Military pilots should refer to appropriate regulations.

Instrument Approach Procedure Charts
Image - b

When a triangle containing an “A” NA (see Image - c) appears in the notes area, it signifies that Alternate Minimums are Not Authorized due to unmonitored facility or the absence of weather reporting service.

Instrument Approach Procedure Charts
Image - c

Communication frequencies are listed in the order in which they would be used during the approach. Frequencies for weather and related facilities are included, where applicable, such as ATIS, ASOS, AWOS, and AFSSs.

The Plan View

The plan view provides a graphical overhead view of the procedure and depicts the routes that guide the pilot from the en route segments to the initial approach fix (IAF). [Figure 1] During the initial approach, the aircraft has departed the en route phase of flight and is maneuvering to enter an intermediate or final segment of the instrument approach. An initial approach can be made along prescribed routes within the terminal area, which may be along an arc, radial, course, heading, radar vector, or a combination thereof. Procedure turns and high-altitude teardrop penetrations are initial approach segments. Features of the plan view, including the procedure turn, obstacle elevation, minimum safe altitude (MSA), and procedure track are depicted in Figure 2. Terrain is depicted in the plan view portion of all IAPs if the terrain within the plan view exceeds 4,000 feet above the airport elevation, or if within a 6 NM radius of the airport reference point the terrain rises at least 2,000 feet above the airport elevation.

Airplane Instrument Approach Procedure Charts
Figure 2. IAP plan view and symbol legends

Some AeroNav Products charts contain a reference or distance circle with a specified radius (10 NM is most common). Normally, approach features within the plan view are shown to scale; however, only the data within the reference circle is always drawn to scale.

Concentric 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 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 normally depicted in the AeroNav Products plan view.

Known spot elevations are indicated on the plan view with a dot in MSL altitude. The largest dot and number combination indicates the highest elevation. An inverted “V” with a dot in the center depicts an obstacle (see Image - d). The highest obstacle is indicated with a bolder, larger version of the same symbol. [Figure 2]

Instrument Approach Procedure Charts
Image - d

The MSA circle appears in the plan view, except in approaches for which the Terminal Arrival Area (TAA) format is used or 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 bearings in the circle. For conventional navigation systems, the MSA is normally based on the primary omnidirectional facility (NAVAID) 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 header is 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 header refers to the letter identifier of the NAVAID or waypoint that describes the center of the circle (see Image - e).

Instrument Approach Procedure Charts
Image - e

NAVAIDs necessary for the completion of the instrument procedure include the facility name, letter identifier, and Morse code sequence. They may also furnish the frequency, Morse code, and channel. A heavy-lined NAVAID box depicts the primary NAVAID used for the approach. An “I” in front of the NAVAID identifier (in Figure 2, “I-AVL”) listed in the NAVAID box indicates a localizer. 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 (see Image - f). A DME arc, which is part of the main procedure course, is also represented as a thick, solid line (see Image - f). A feeder route is depicted with a medium line (see Image - f) 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 (see Image - f). The missed approach track is drawn using a thin, hash marked line with a directional arrow (see Image - g). A visual flightpath segment appears as a thick dashed line with a directional arrow (see Image - h). IAFs are charted IAF when associated with a NAVAID or when freestanding.

Instrument Approach Procedure Charts
Image - f

Instrument Approach Procedure Charts
Image - g

Instrument Approach Procedure Charts
Image - h

The missed approach holding pattern track is represented with a thin, dashed line. When collocated, 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.

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