Definition
An FAA publication that provides detailed information about airports, heliports, and seaplane bases in the United States, including runway data, communication frequencies, services available, airport remarks, and special procedures not shown on aeronautical charts.
Plain English
A book of detailed information about every public airport in a region — things like runway lengths, who to call on the radio, what fuel and services are available, and any local quirks pilots need to know.
Context Anchor
Used during preflight planning and in flight when checking airport details, frequencies, services, or notes that are too detailed to fit on the chart itself.
Derivation
Formerly called the Airport/Facility Directory (A/FD), it was renamed Chart Supplement because it supplements the information shown on aeronautical charts. The charts show the airport symbol and basic data; the supplement provides the full details that won't fit on a chart.
Why Pilots Care
It supplies runway lengths, fuel availability, lighting, frequencies, and other operational details required for safe airport selection and use.
Intuition Check
Do not think of a Chart Supplement as an optional extra chart. It is an official reference publication that supports the chart by giving details the chart cannot show clearly.
Example Sentence 1
Before the cross-country, she pulled up the Chart Supplement to check the runway length and fuel availability at her destination.
Example Sentence 2
During flight planning the student checked the Chart Supplement for runway lengths and services before filing the cross-country route.