Definition
A civil flight information publication that lists data for airports, seaplane bases, and heliports open to the public, along with communications frequencies, navigation aids, instrument landing systems, and related services within a defined region of the United States. Historically published by the FAA in seven regional booklets and updated every 56 days, the A/FD has since been renamed and incorporated into the Chart Supplement U.S., though the term A/FD is still widely used in legacy handbooks and pilot conversation.
Plain English
A reference book that tells pilots what they need to know about airports and the services around them — runway lengths, radio frequencies, fuel availability, lighting, and so on. It used to be called the A/FD; today the same publication is called the Chart Supplement.
Context Anchor
Seen during preflight planning, especially when checking airport details that may not fit on a chart.
Derivation
The name is descriptive: a directory (a listed reference) of airports and the facilities (services and equipment) at each one. Knowing this helps the reader expect a structured, entry-by-entry reference rather than a narrative document.
Why Pilots Care
It supplies the specific details needed to choose suitable airports, confirm available services, and avoid operational surprises.
Analogy
It is like a detailed operating guide for airports, not just a map. A chart shows where the airport is; the A/FD gives many of the details needed to use it correctly.
Intuition Check
Do not read “directory” as just a list of names and phone numbers. In aviation, the Airport/Facility Directory is an operational reference with details pilots may need before using an airport.
Example Sentence 1
Before her cross-country flight, she opened the A/FD to check the runway length and CTAF frequency at her destination.
Example Sentence 2
Updates in the A/FD alerted the crew to a new frequency for the local approach control.