; and (2) by inserting after subsection (g) (as added by section 725), the following: (h) Milestones for design approval of remote towers (1) In general Not later than 180 days after the date of enactment of this subsection, the Administrator of the Federal Aviation Administration shall create a structured program and publish milestones to achieve system design approval for a remote tower system. (2) Requirements In carrying out subparagraph (A), the Administrator shall— (A) rely on support from the Airports Office of the Federal Aviation Administration and the Air Traffic Organization of the Federal Aviation Administration, including the Air Traffic Services Service Unit and the Technical Operations Service Unit; and (B) not later than September 30, 2024, expand validation and certification of system design approval for a digital or remote tower system to three locations outside of the William J. Hughes Technical Center, as specified in section 161 of the FAA Reauthorization Act of 2018 ( 49 U.S.C. 47104 note). . (b) Conforming amendments Section 47124(b) of title 49, United States Code, is amended— (1) in paragraph (3)(B)(ii), by inserting or a remote airport traffic control tower that has received System Design Approval (SDA) from the Federal Aviation Administration after an operating air traffic control tower ; and (2) in each of clauses (i)(III) and (ii)(III) of paragraph (4)(A), by inserting or remote air traffic control tower equipment that has received System Design Approval (SDA) from the Federal Aviation Administration after certified by the Federal Aviation Administration . 620. Grant assurances Section 47107(a) of title 49, United States Code, is amended— (1) in paragraph (7), by striking the semicolon and inserting , such that there are no unsafe practices or conditions as determined by the Secretary; ; (2) in paragraph (20), by striking and after the semicolon; (3) in paragraph (21), by striking the period at the end and inserting a semicolon