This Advisory Circular (AC) describes the Federal Aviation Administration (FAA) Air Traffic Organization (ATO) requirements and process for the assignment and authorization for use of aircraft call signs, specifically, International Civil Aviation Organization (ICAO) three-letter designators (3LD), U.S. special designators, local designators, and their associated telephonies.

This Advisory Circular (AC) provides the general public with a common use document thatdescribes the Plan for Emergency Security Control of Air Traffic (ESCAT), and its purposefor use by civil aviation.

This Advisory Circular (AC) provides information to aircrews, operating within the National Airspace System (NAS), and the broader aviation community on measures taken by the Federal Aviation Administration (FAA) to address incidents of unauthorized illumination of aircraft by lasers.