; and (2) whether a certificate of waiver, certificate of authorization, or airworthiness certification under section 44704 is required for the operation of unmanned aircraft systems identified under paragraph (1). (c) Requirements for Safe Operation If the Secretary determines under this section that certain unmanned aircraft systems may operate safely in the national airspace system, the Secretary shall establish requirements for the safe operation of such aircraft systems in the national airspace system. 45506. Certification of new air navigation facilities for unmanned aircraft and other aircraft (a) In general Not later than 18 months after the date of enactment of this section, and notwithstanding section 2208 of the FAA Extension, Safety, and Security Act of 2016 ( 49 U.S.C. 40101 note), the Administrator of the Federal Aviation Administration shall initiate a rulemaking to establish procedures for issuing air navigation facility certificates pursuant to section 44702 to operators of— (1) UTM for unmanned aircraft operations that occur primarily or exclusively in airspace 400 feet above ground level and below