; and (E) shall require that any technology, system, or equipment procured pursuant to this subsection be procured using non-Federal funds, except as made available under a grant issued pursuant to 47124(b)(4). (g) Liability insurance (1) In general Not later than 18 months after the date of enactment of this subsection, the Secretary shall consult with aviation industry experts, including air traffic control contractors and aviation insurance professionals, to determine adequate limits of liability for the Contract Tower Program. (2) Interim steps Not later than 6 months after the date of enactment of this subsection and until the Secretary makes a determination on liability limits under paragraph (1), the Secretary shall require air traffic control contractors to have excess liability insurance (as determined by the Secretary) to ensure continuity of such coverage should a major accident occur. (3) Briefing Not later than 24 months after the date of enactment of this subsection, the Secretary shall brief the Committee on Transportation and Infrastructure of the House of Representatives and the Commerce, Science, and Transportation of the Senate on the findings, conclusions, and actions taken and planned to be taken to carry out this subsection. . 621. Remote towers (a) In general Section 47124 of title 49, United States Code, is further amended— (1) by adding at the end 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 program and publish milestones to achieve system design and operational approval for a remote tower system. (2) Requirements In carrying out paragraph (1), the Administrator shall— (A) rely on support from the Office of Airports 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