49 CFR § 190.227 - Payment of penalty.
(a) Except for payments exceeding $10,000, payment of a civil penalty proposed or assessed under this subpart may be made by certified check or money order (containing the CPF Number for the case), payable to “U.S. Department of Transportation,” to the Federal Aviation Administration, Mike Monroney Aeronautical Center, Financial Operations Division (AMZ–341), P.O. Box 25770, Oklahoma City, OK 73125, or by wire transfer through the Federal Reserve Communications System (Fedwire) to the account of the U.S. Treasury, or via https://www.pay.gov. Payments exceeding $10,000 must be made by wire transfer.
(b) Payment of a civil penalty assessed in a final order issued under § 190.213 or affirmed in a decision on a petition for reconsideration must be made within 20 days after receipt of the final order or decision. Failure to do so will result in the initiation of collection action, including the accrual of interest and penalties, in accordance with 31 U.S.C. 3717 and 49 CFR part 89.