Definition
Non-regulatory documents issued by the FAA that provide guidance, recommended practices, and explanatory information on subjects related to aviation safety, training, certification, and operations. Advisory circulars (ACs) are numbered to correspond with the subject areas of the Federal Aviation Regulations and, while generally not binding, often represent the FAA's accepted methods of compliance.
Plain English
Official FAA guidance papers that explain how to do things the FAA's way. They are not rules themselves, but they tell you what the FAA considers acceptable practice.
Context Anchor
Seen in FAA handbooks, instructor training, maintenance guidance, and lesson or test planning when a person needs an official FAA explanation beyond the regulation itself.
Derivation
‘Advisory’ comes from Latin advisare, meaning ‘to give counsel or advice.’ ‘Circular’ comes from Latin circularis, meaning a written notice meant to be circulated widely. Together: a widely distributed document offering guidance rather than commands.
Why Pilots Care
Although ACs are not regulations, they describe the FAA's preferred way of meeting a regulation. Following the guidance in an AC is usually the easiest way to demonstrate compliance and show good faith during checkrides, inspections, or investigations.
Intuition Check
Advisory does not mean casual or unofficial here. It means FAA-issued guidance that may be highly important, even when it is not a regulation by itself.
Example Sentence 1
The instructor pointed students to the relevant advisory circular for additional detail on stall awareness training.
Example Sentence 2
Student pilots benefit from reviewing the Advisory Circular on flight training when planning their own study sequence.