14 CFR § 151.63 - Grant payments: Semifinal and final.
(a) Whenever airport development on a project is delayed or suspended for an appreciable period of time for reasons beyond the sponsor's control and the allowability of the project costs of all airport development completed has been determined on the basis of an audit and review of all costs, a semifinal grant payment may be made in an amount large enough to bring the aggregate amount of all partial grant payments for the project to the United States share of all allowable project costs incurred, even if the amount is more than the 90 percent limitation prescribed in § 151.61(b). However, it may not be more than the maximum obligation of the United States as stated in the grant agreement.
(b) Whenever the project is completed in accordance with the grant agreement, the sponsor may apply for final payment. The final payment is made to the sponsor if—
(1) A final inspection of all work at the airport site has been made jointly by the Area Manager and representatives of the sponsor and the contractor, unless the Area Manager agrees to a different procedure for final inspection.
(2) A final audit of the project account has been completed by appropriate personnel of the FAA; and
(3) The sponsor has furnished final “as constructed” plans, unless otherwise agreed to by the Administrator.
(c) Based upon the final inspection, the final audit, the plans, and the documents and supporting information required by § 151.57(a), the Administrator determines the total amount of the allowable project costs and pays the sponsor the United States' share, less the total amount of all prior payments.