49 CFR § 1503.639 - Burden of proof.

---
identifier: "/us/cfr/t49/s1503.639"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 1503.639 - Burden of proof."
title_number: 49
title_name: "Transportation"
section_number: "1503.639"
section_name: "Burden of proof."
chapter_name: "TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "A"
subchapter_name: "ADMINISTRATIVE AND PROCEDURAL RULES"
part_number: "1503"
part_name: "INVESTIGATIVE AND ENFORCEMENT PROCEDURES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: ": 6 U.S.C. 1142; 18 U.S.C. 6002; 28 U.S.C. 2461 (note); 49 U.S.C. 114, 20109, 31105, 40113-40114, 40119, 44901-44907, 44939, 46101-46107, 46109-46110, 46301, 46305, 46311, 46313-46314; Pub. L. 110-53 (121 Stat. 266, Aug. 3, 2007) secs. 1408 (6 U.S.C. 1137), 1501 (6 U.S.C. 1151), 1517 (6 U.S.C. 1167), and 1534 (6 U.S.C. 1184)."
regulatory_source: "74 FR 36039, July 21, 2009, unless otherwise noted."
cfr_part: "1503"
---


# 1503.639 Burden of proof.

(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.