14 C.F.R. § 39.3 Definition of airworthiness directives.
Title 14 - Aeronautics and Space
FAA's airworthiness directives are legally enforceable rules that apply to the following products: aircraft, aircraft engines, propellers, and appliances.
Title 14: Aeronautics and Space
PART 39—AIRWORTHINESS DIRECTIVES
§ 39.3 Definition of airworthiness directives.
