; and (2) ensure that complying with the advisory circular will not require an air carrier or foreign air carrier to incur significant expense, such as through the addition of an extra crewmember in response to providing a break, removal or retrofitting of seats on the aircraft, or modification or retrofitting of an aircraft. (b) Definitions In this section: (1) Crewmember The term crewmember has the meaning given such term in section 1.1 of title 14, Code of Federal Regulations. (2) Critical phases of flight The term critical phases of flight has the meaning given such term in section 121.542 of title 14, Code of Federal Regulations. (3) Part 121 The term Part 121 means part 121 of title 14, Code of Federal Regulations. (c) Aviation safety Nothing in this section shall limit the Administrator’s authority over aviation safety under subtitle VII of title 49, United States Code. 343. Reauthorization of certain provisions of the Aircraft Certification, Safety, and Accountability Act (a) Oversight of organization designation authorization unit members Section 44741 of title 49, United States Code, is amended— (1) in subsection (f)(2), in the matter preceding subparagraph (A), by striking September 30, 2023 and inserting September 30, 2028