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Deciphering Key Elements in the Chart Supplement

News > Deciphering Key Elements in the Chart Supplement

Chart Supplements are an incredibly useful source of information, providing extensive data regarding the airport environment. They are designed to be used in conjunction with Sectional Charts, High Enroute Charts, Low Enroute Charts, or other visual charts published by the FAA. Chart Supplements contain an Airport/Facility Directory (A/FD), notices, associated data, and airport diagrams.

An airport’s A/FD listing should always be analyzed prior to flight into an unfamiliar airport to better understand the airport environment. The information is often codified, and although you are not expected to know every detail within an A/FD listing, at minimum you should know where to find its description within the legend. In this article, we will point out five key pieces of information within an airport’s A/FD listing that you may have overlooked in the past and that will be useful in planning future flights.


At the top of the Airport/Facility Directory listing for each airport, you will find basic information about the airport. One piece of information students are often unsure of here is elevation. The airport elevation is simply a number in the top section. More often than not, this is a positive number. However, if the elevation is at mean sea-level, it will be coded as “00.” If it is below mean sea-level, it will be a negative number, as in the example for Furnace Creek Airport (L06) in Death Valley, California.

Chart Information

Have you ever wondered which specific Sectional, High Enroute, or Low Enroute Chart you should analyze for your selected airport? The airport’s A/FD listing has the answer. At the top-right corner of the listing is a list of all the associated charts you may utilize with the supplement. In our example, we have the Miami International Airport A/FD. You may refer to the Miami Sectional Chart, the “H-8I” High-Altitude Chart, or the “L-23C” Low-Altitude Chart. Other charts that may be listed in this corner are “P” for Pacific Enroute, “A” for Area Enroute, “COPTER” for Helicopter Chart, “GOMW” for IFR Gulf of Mexico West, and “GOMC” for IFR Gulf of Mexico Central.

The A/FD listing may also include the codes IAP, DIAP, and AD in this corner if a prescribed FAA Instrument Approach Procedure, DoD Instrument Approach Procedure, or airport diagram has been published.

Weather Data Sources

The weather frequencies for an airport can be found in the Weather Data Sources section. However, this section often includes a phone number you may call to listen to the latest weather report for the airport. This can be a useful tool to obtain a quick weather update, particularly in areas with poor internet connectivity. There are a variety of weather stations that can be coded here such as AWOS for Automated Weather Observing System and TDWR for Terminal Doppler Weather Radar. The different types of weather stations and their descriptions can be found in the Chart Supplement legend.


Under the Services section of an airport’s A/FD listing, you can find information for maintenance, fuel, and oxygen refills available at the airport. Each of these services have different degrees to them and are coded accordingly in the listing. For example, at Miami International Airport, services are available to provide “S4” maintenance, which includes major airframe and powerplant repairs. Additionally, Avgas 100 and Jet A fuel can be purchased. Finally, oxygen refills are available.

Such information can be helpful when you are attempting to locate an airport that can provide the type of maintenance you require, the correct fuel for your airplane, or the type of oxygen refill you need. The last thing you want to do is to be low on fuel and land at an airport without the fuel you need. Refer to the Chart Supplement legend for the different services codes. Don’t forget to check NOTAMS, which may advise if fuel service is temporarily unavailable.

Runway Data

Finally, we have the Runway Data section. Information such as runway dimensions, material, grooved or non-grooved, the weight bearing capacity, the pavement classification number (PCN), and lighting is available. In our example, the PCN number is 80, which means an aircraft with an ACN equal or less than the reported PCN can operate on the pavement subject to any limitation on the tire pressure. Separate information specific to each end of the runway includes lighting, slope and threshold crossing height (TCH), and runway end data. The end data may also contain information such as additional lights, right traffic pattern, obstructions, and displaced threshold. This section of the listing can be particularly useful at night when we verify runways according to the different lighting systems. Refer to the Chart Supplement legend for the different runway data codes.

There is plenty of other key information available in the Airport/Facility Directory listing. You may be surprised by the information you could find by inspecting the listing of your home airport. Your home airport may even have some special interest remarks, such as a woodchuck in Punxsutawney, PA (think Groundhog Day). Becoming familiar with the different sections and codes in the A/FD listing is crucial to improving your situational awareness, as you will be more informed of the airport environment and services available.

All pilots should have the ability to decipher complex charts, codes, and acronyms. Fortunately, all the different forms of charts provided by the FAA include a legend that explains each number, symbol, or even color you may see on a chart. Developing this analytical skill will also help pilots decipher unfamiliar charts and legends. When you analyze a chart, whether in the POH or an FAA publication, remember that every line of text is essential. When you take an FAA knowledge test, you may see questions relating to chart symbols. The computer testing supplement which contains all the images for your test also contains legends that may hold the key to answering many test questions. To help you prepare for the knowledge test and gain familiarity with the relevant charts and legends, pick up a copy of the Gleim Knowledge Test Prep Book for your certificate or rating.

Written by: Ryan Jeff, Aviation Research Assistant

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