14 CFR 39.7 : Aeronautics And Space (§ 1.1 To Parts 1311-1399) — (§ 1.1 To Parts 50-59) — Federal Aviation Administration, Department Of Transportation (§ 1.1 To Parts 50-59) — Aircraft (§ 21.1 To Parts 50-59) — Airworthiness Directives (§ 39.1 To § 39.27) — What is the legal effect of failing to comply with an airworthiness directive?