Definition
The digital Chart Supplement (d-CS) is the FAA's electronic version of the Chart Supplement, a publication containing detailed information on airports, heliports, seaplane bases, navigation aids, communication frequencies, special notices, and operational procedures for a specific U.S. region. The d-CS is distributed as a downloadable PDF and updated on the same 56-day cycle as the printed booklet, providing the same official content in a searchable, screen-friendly format.
Plain English
It's the FAA's airport and airspace reference book, in digital form. Pilots use it to look up runway details, frequencies, services, and local procedures for any airport in their region.
Context Anchor
Seen when using FAA digital publications for preflight planning, airport information, and instrument procedure preparation.
Derivation
‘Chart Supplement' means a publication that supplements (adds to) the information already shown on aeronautical charts. The ‘d-' prefix simply marks it as the digital edition. The publication was previously called the Airport/Facility Directory (A/FD), which is why some older pilots still refer to it by that name.
Why Pilots Care
It supplies the most current textual airport and procedure data needed for safe flight planning and in-flight reference without requiring physical paper copies.
Intuition Check
Do not read “supplement” as something unimportant or optional. In this term, Chart Supplement is the name of an FAA publication that adds necessary details to the chart.
Example Sentence 1
Before the cross-country, she downloaded the latest d-CS for the South Central region and checked the airport diagram and CTAF frequency for her destination.
Example Sentence 2
The d-CS update added new taxiway markings at the destination airport.