49 CFR §1016.301

1. (a)An application may be filed whenever the applicant has prevailed in the proceeding or in a significant and discrete substantive portion of the proceeding, but in no case later than 30 days after an administratively final disposition of the proceeding.
2. (b)If review or reconsideration is sought or taken of a decision as to which an applicant believes it has prevailed, proceedings for the award of fees shall be stayed pending final disposition of the underlying controversy.
3. (c)For purposes of this rule, see the Board's rules governing appellate procedures at §§ 1115.2 and 1115.3 to determine when a decision becomes administratively final.