Definition
Non-regulatory documents issued by the FAA to provide guidance, recommended practices, methods, and information to pilots, instructors, mechanics, and operators on a wide range of aviation subjects. Advisory circulars explain how to comply with regulations, share accepted procedures, and offer educational material, but they generally do not carry the force of law unless specifically incorporated by reference into a regulation.
Plain English
Official FAA guidance papers that explain how to do things the right way. They give advice and accepted methods, but most of them are not rules you must follow.
Context Anchor
Flight instructors encounter ACs when looking up FAA guidance on teaching, training endorsements, aircraft operation, maintenance practices, and safety recommendations.
Derivation
‘Advisory’ comes from Latin advisare, meaning ‘to give counsel or advice.’ ‘Circular’ refers to a document circulated, or distributed widely, to a group. Together the term means ‘a widely distributed advice document’ — which is exactly what these are.
Why Pilots Care
They give practical explanations that help instructors teach regulations clearly without forcing students to interpret legal text.
Intuition Check
Do not assume advisory means unimportant. An AC is usually guidance, not a rule by itself, but it is still official FAA guidance and may become required if another official document says so.
Example Sentence 1
The instructor pointed the student to the relevant advisory circular for guidance on weight and balance calculations.
Example Sentence 2
New pilots often read advisory circulars to understand how regulations apply during flight training.