; (2) may issue such regulations as are necessary to require the appropriate level and amount of simulator training for pilots based on science and proficiency for each defined task or training objective; and (3) if the Administrator does not issue regulations under paragraph (2), shall publish in the Federal Register an explanation of the reason that the Administrator did not issue such regulations. (d) Definitions In this section, the terms air carrier and aircraft have the meanings given such terms in section 40102 of title 49, United States Code.