Chapter 11: Airport Operations  • Chart Supplement U.S. (formerly Airport/Facility Directory) • Notices to Airmen (NOTAMs) • Automated Terminal Information Service (ATIS) The Chart Supplement U.S. (formerly Airport/Facility Directory) provides the most comprehensive  information on a given airport. It contains information on airports, heliports, and seaplane bases  that are open to the public. The Chart Supplement U.S. is published in seven books, which are  organized by regions and are revised every 56 days. The Chart Supplement U.S. is also available  digitally at  www.faa.gov/air_traffic/flight_info/aeronav.  Figure 11-1  contains an excerpt from a  directory. For a complete listing of information provided in a Chart Supplement U.S. and how the  information may be decoded, refer to the “Legend Sample” located in the front of each Chart  Supplement U.S.  Time-critical aeronautical information, which is of a temporary nature or not sufficiently known in  advance to permit publication, on aeronautical charts or in other operational publications, that  receives immediate dissemination by the NOTAM system. The NOTAM information could affect your  Figure 11-1.  Chart Supplement U.S. (formerly Airport/Facility Directory excerpt. Chart Supplement U.S. (formerly Airport/Facility Directory) Notices to Airmen (NOTAM) Remote Pilot – Small Unmanned Aircraft Systems Study Guide  66