(a) If the amount of PFC revenue remitted to the public agency, plus interest, exceeds allowable costs of the project, excess funds shall be used for approved projects or retirement of outstanding PFC-financed bonds.

(b) For bond-financed projects, any excess PFC revenue collected under debt servicing requirements shall be retained by the public agency and used for approved projects or retirement of outstanding PFC-financed bonds.

(c) When the authority to impose a PFC has expired or has been terminated, accumulated PFC revenue shall be used for approved projects or retirement of outstanding PFC-financed bonds.

(d) Within 30 days after the authority to impose a PFC has expired or has been terminated, the public agency shall present a plan to the appropriate FAA Airports office to begin using accumulated PFC revenue. The plan shall include a timetable for the submission of any necessary application under §158.25(c) of this part. If the public agency fails to submit such a plan or if the plan is not acceptable to the Administrator, the Administrator offsets Federal airport grant program apportioned funds.