; and (D) any other representatives the Administrator determines appropriate. (4) Submission of plan Not later than 15 months after the date of enactment of this Act, the Administrator shall submit to the appropriate committees of Congress the plan required under this subsection. (5) Implementation Not later than 18 months after the date of enactment of this Act, the Administrator shall initiate such actions necessary to implement the plan developed under paragraph (1), including initiating any required rulemaking. (6) Definition In this subsection, the term certain NextGen avionics means those avionics and baseline capabilities as recommended in the report of the NextGen Advisory Committee titled Minimum Capabilities List (MCL) Ad Hoc Team NAC Task 19–1 Report , issued on November 17, 2020. (h) Effect of failure to meet deadline (1) Notification of Congress For each deadline established under subsections (a) through (g), if the Administrator determines that the Administrator has not met or will not meet each such deadline, the Administrator shall, not later than 30 days after such determination, notify the appropriate committees of Congress about the failure to meet each deadline. (2) Contents of notification Each notification under paragraph (1) shall be accompanied by the following: (A) An explanation as to why the Administrator will not or did not meet the deadline described in such paragraph. (B) A description of the actions the Administrator plans to take to meet the deadline described in such paragraph. (C) Actions Congress can take to assist the Administrator in meeting the deadline described in such paragraph. (3) Briefing If the Administrator is required to provide notice under paragraph (1), the Administrator shall provide the appropriate committees of Congress quarterly briefings as to the progress made by the Administrator regarding implementation under the respective subsection for which the deadline will not be or was not met until such time as the Administrator has completed the required work