(i) Begin to carry out the plan within 6 months of its approval; and

(ii) Except as provided in paragraph (2) of this subsection, fully carry out the plan within 18 months of its approval.

(2) The Executive Director may grant a delay of up to 2 years to carry out the plan fully if the Executive Director finds that, despite the good faith efforts of the operator, the operator cannot comply with the schedule required by this subsection.

(b) After notice and a public hearing, the Executive Director shall certify and publish, as a noise zone for purposes of Parts III and IV of this subtitle, any noise zone that results from an approved assessment or an approved plan.

(c) On application by the airport operator or an affected political subdivision, the Executive Director shall consider any adjustment to an approved plan or noise zone that is needed to reflect potential operational changes, changes in adjoining land uses, or other factors. Adjustments may be made only by recertification of the noise zone by the Executive Director, after notice and a public hearing.

(d) Before any hearing under this section, the Executive Director shall give the chief executive officer and zoning board of any affected political subdivision an opportunity to comment. After certification of a noise zone, the Administration shall notify them of the certified noise zone.

(e) The Executive Director may adopt rules and regulations for monitoring compliance with approved plans.