FAA Advisory Circular

Flight instructor and student inside small Piper aircraft
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If you've ever had trouble interpreting a federal aviation regulation, then you may have found some clarification in an advisory circular. FARs can be so complex — they're written in legal language that many aviation experts cannot decipher clearly, not to mention they're entirely too lengthy and always seem to include a list of exceptions that reference about eight additional FARs. Those FARs then lead you to even more FARs that you can't explain. For most of us, advisory circulars are big messes that we never fully understand. Many pilots simply hope that there is no legal trouble and know that if there is, they must succumb to the fact that the legal interpretation of the rules is ultimately up to our government.

Interpreting Rules

Take, for example, the determination of a pilot's ability to log time for currency and training in a simulator or flight training device. Over time, questions arose about what makes a simulator a simulator, and whether or not a simulator or flight training device could, or should, be used for landing proficiency. Should a student be able to log instrument time in a simulator without an instructor present? What if a component of the simulator is inoperative? Can you still log time? How exactly do you log simulator time? Eventually, these questions came to be answered in Advisory Circular 61-13, which clarifies most questions surrounding the use of basic and advanced training devices and flight simulators. 

It's never fun to be in the gray area when regulations are at stake. Advisory circulars help bring us back to a black and white area sometimes. 

Advisory Circulars are informational documents produced by the Federal Aviation Administration to inform and guide institutions and individuals within the aviation industry, as well as the general public. Advisory Circulars are intended to be informative in nature and not regulatory; however, many times they describe actions or advice that the FAA expects to be implemented or followed.

ACs can be distributed by the FAA to an audience of pilots, mechanics, operators, airport managers, manufacturers, and the general public. The subject of advisory circulars typically involves aircraft, airports, flight schools, pilots, operations, or maintainers. Advisory circulars can be directional, informational or descriptive. They often describe how the FAA wants things should be done, best practices for operations, or clarification of a new regulation.

The FAA issues advisory circulars for many reasons. Standardization is one common reason. As there are often many ways to interpret regulations and many ways to implement a specific operation, an advisory circular can offer specific guidelines for the aviation industry when the regulations or requirements are otherwise vague.

Advisory Circulars can also be distributed as a safety precaution, such as to notify pilots of an equipment malfunction or a rule change, like the pilot fatigue and duty requirement regulations that were recently changed.


There are advisory circulars for everyone and everything involved in aviation: pilots and airman, aircraft and airworthiness, airspace, general operating rules, air carriers, flight schools, and airports. It may sound familiar, as this format follows the same format to the actual FARs. 

A well-known example of an advisory circular is AC-No 120-76A, which involves guidelines for the use of electronic flight bags (EFBs) and other electronic onboard equipment. The introduction of the iPad and other tablet devices made this advisory circular necessary for standardizing the use of EFBs during different types of flying environments.