49 CFR 1542.203 - Security of the air operations area (AOA).
(b) Each airport operator required to establish an AOA must prevent and detect the unauthorized entry, presence, and movement of individuals and ground vehicles into or within the AOA by doing the following:
(2) Provide for detection of, and response to, each unauthorized presence or movement in, or attempted entry to, the AOA by an individual whose access is not authorized in accordance with its security program.
(4) Post signs on AOA access points and perimeters that provide warning of the prohibition against unauthorized entry to the AOA. Signs must be posted by each airport operator in accordance with its security program not later than November 14, 2003.
(5) If approved by TSA, the airport operator may designate all or portions of its AOA as a SIDA, or may use another personnel identification system, as part of its means of meeting the requirements of this section. If it uses another personnel identification system, the media must be clearly distinguishable from those used in the secured area and SIDA.