14 C.F.R. § 14.29
If an applicant is dissatisfied with the determination of fees and other expenses made under this subsection, pursuant 5 U.S.C. 504(c)(2) , that applicant may, within thirty (30) days after the determination is made, appeal the determination to the court of the United States having jurisdiction to review the merits of the underlying decision of the FAA adversary adjudication. The court's determination on any appeal heard under this paragraph shall be based solely on the factual record made before the FAA. The court may modify the determination of fees and other expenses only if the court finds that the failure to make an award of fees and other expenses, or the calculation of the amount of the award, was unsupported by substantial evidence.
14 C.F.R. § 14.29