14 C.F.R. § 13.224 Burden of proof.
Title 14 - Aeronautics and Space
(a) Except in the case of an affirmative defense, the burden of proof is on the agency. (b) Except as otherwise provided by statute or rule, the proponent of a motion, request, or order has the burden of proof. (c) A party who has asserted an affirmative defense has the burden of proving the affirmative defense.
Title 14: Aeronautics and Space
PART 13—INVESTIGATIVE AND ENFORCEMENT PROCEDURES
Subpart G—Rules of Practice in FAA Civil Penalty Actions
§ 13.224 Burden of proof.