Advisory Circular 91-57 Canceled and Updated with AC 91-57A.

Advisory Circular 91-57  was originally published June 9, 1981 and had been current for 34 years, 2 months, 24 days. Interestingly, it was accidentally canceled on August 10, 2014 by the FAA. On September 2, 2015, the FAA canceled it and published Advisory Circular 91-57A.

Let’s get into the analysis.

Compare Background Sections

1981 AC 91-57

2015 AC 91-57A

Modelers, generally, are concerned about safety and do exercise good judgement when flying model aircraft. However, model aircraft can at times pose a hazard to full-scale aircraft in flight and to persons and property on the surface. Compliance with the following standards will help reduce the potential for that hazard and create a good neighbor environment with affected communities and airspace users.Model Aircraft Hazards in the NAS. While aero-modelers generally are concerned about safety and exercise good judgment when flying model aircraft for the hobby and recreational purposes for which they are intended, they may share the airspace in which manned aircraft are operating. Unmanned aircraft, including model aircraft, may pose a hazard to manned aircraft in flight and to persons and property on the surface if not operated safely. Model aircraft operations that endanger the safety of the National Airspace System, particularly careless or reckless operations or those that interfere with or fail to give way to any manned aircraft may be subject to FAA enforcement action.



Compare and Contrast Operational Restrictions

1981 AC 91-572015 AC 91-57A
Do not fly model aircraft higher than 400 feet above the surface.


Model aircraft operators should follow best practices including limiting operations to 400 feet above ground level (AGL).
When flying aircraft within 3 miles of an airport, notify the airport operator, or when an air traffic facility is located at the airport, notify the control tower, or flight service station.When flown within 5 miles of an airport, the operator of the model aircraft provides the airport operator or the airport air traffic control tower (when an air traffic facility is located at the airport) with prior notice of the operation. Model aircraft operators flying from a permanent location within 5 miles of an airport should establish a mutually agreed upon operating procedure with the airport operator and the airport air traffic control tower (when an air traffic facility is located at the airport).
Give right of way to, and avoid flying in the proximity of, full-scale aircraft. Use observers to help if possible.The aircraft operates in a manner that does not interfere with, and gives way to, any manned aircraft.
Nothing SimilarThe aircraft is limited to not more than 55 pounds, unless otherwise certified through a design, construction, inspection, flight test, and operational safety program administered by a CBO
Select an operating site that is of sufficient distance from populated areas. The selected site should be away from noise sensitive areas such as parks, schools, hospitals, churches, etc.


The aircraft operates in accordance with a community-based set of safety guidelines and within the programming of a nationwide community-based organization (CBO)
Do not operate model aircraft in the presence of spectators until the aircraft is successfully flight tested and proven airworthy


Nothing Similar
Nothing SimilarThe aircraft is flown strictly for hobby or recreational use

Compare Voluntary Compliance

1981 AC 91-57

2015 AC 91-57A

This advisory circular outlines, and encourages voluntary compliance with, safety standards for model aircraft operators.Public Law 112-95 recognizes the authority of the Administrator to pursue enforcement action against persons operating model aircraft who endanger the safety of the National Airspace System. Accordingly, model aircraft operators must comply with any Temporary Flight Restrictions (TFR). TFRs are issued over specific locations due to disasters, or for reasons of national security; or when determined necessary for the management of air traffic in the vicinity of aerial demonstrations or major sporting events. Do not operate model aircraft in designated areas until the TFR is no longer in force. Model aircraft must not operate in Prohibited Areas, Special Flight Rule Areas or, the Washington National Capital Region Flight Restricted Zone, without specific authorization.


The two big take-aways are that the airport notification radius was increased to 5 miles and that the FAA believes model aircraft must, not voluntarily, comply.


This advisory circular falls short by not fully explaining how model aircraft flyers can operate near an airport.


  • It says 5 miles but it is unclear as to nautical or statute miles.
  • It also does not define airport. This is important because there are many private airports all over the place. How do model aircraft flyers get in touch with these airports? Do I have to pull the property records and mail the owner a letter so I can plan a flight in a couple weeks? The airport facility directory does not list all the airports with a phone number for me to call. Furthermore, the AFD’s have the airport manager phone numbers in them so I can call them and ask to get the tower’s number. What happens if I’m wanting to fly after getting off of work and all I have is the airport manager’s phone number who left at 5PM? I can’t fly because I can’t notify the tower via phone. My only other choice is to get an aviation handheld transceiver which only has limited range and could sound horrible at 5 miles.
  • It does not clarify as to what the model aircraft operator must do if the tower tells them to not fly within their airspace. 14 C.F.R. § 91.123 (b) says, “Except in an emergency, no person may operate an aircraft contrary to an ATC instruction in an area in which air traffic control is exercised.” To get even more technical, Class B airports require clearances, while Class C and D airports require only two way radio contact. See 14 C.F.R §§ 91.131(a)(1); 91.129(c); 91.130(c). Do I have to get a “clearance” to fly in Class B? The FAA charged David Zablidowsky with flying in Class B without a clearance and he was a recreational flyer.   Since I have two flight instructor certificates and a commercial certificate, I’m totally not flying in a Class B until I get the tower telling me that I’m cleared. If I’m flying in a Class C or D airport, does the simple phone call suffice for two way radio contact?  After all, this is just an ADVISORY circular while I just referenced hard regulations with the force of law behind them and the FAA used one of them in a prosecution!
  • It does NOT clearly advise non-pilots of what they are required to comply with to safely operate in the national airspace. The new AC says, “Nothing in this AC changes the requirement to comply with the statute or any applicable regulations.” The regulations I just listed above were NOT clarified and this AC gives model aircraft operators a false sense of security.
  • It does not echo what was said in the 2014 Model Aircraft Rule Interpretation. For Example here is a list of what is said in the 2014 2014 Model Aircraft Interpretation but NOT in the new AC:
    • “The aircraft must be visible at all times to the operator[.]”
    • Do not fly the aircraft beyond visual line-of-sight.
    • “[T]he operator must use his or her own natural vision (which includes vision corrected by standard eyeglasses or contact lenses) to observe the aircraft.” You cannot use “vision-enhancing devices, such as binoculars, night vision goggles, powered vision magnifying devices, and goggles designed to provide a ‘first-person view’ from the model.”
    • “[P]eople other than the operator may not be used in lieu of the operator for maintaining visual line of sight.”
  • It did not clarify how close model aircraft flyers can fly to people. The FAA mentioned in their Model Rule Interpretation § 91.119(c) which says do not operate the aircraft in a non-congested area “closer than 500 feet to any person, vessel, vehicle, or structure.” Model aircraft “may still pose a risk to persons and property on the ground warranting enforcement action when conducted unsafely.” However, in the Know Before You Fly campaign which the FAA partnered with, it says, “Do not intentionally fly over unprotected persons or moving vehicles, and remain at least 25 feet away from individuals and vulnerable property.” This distance requirement is unclear.

In the back of my book, I had to compile everything into a chart that  the FAA said regarding model aircraft because the FAA has said certain things and not echoed them elsewhere. If we are going chronologically, is this the most up-to-date interpretation and we should just ignore the 2014 Model Aircraft Interpretation? If it is both/and, then how in the world is this even advisory?


Put it all down in one place.


Jonathan Rupprecht

Mr. Rupprecht is an aviation attorney who focuses on drones. Read more about his background as a commercial pilot, flight instructor, Embry-Riddle Aeronautical University grad, and legal author. He has had media appearances on Forbes, Newsweek, Politico, NPR, Marketwatch, The Independent, Motherboard, and other sources. Feel free to send Jonathan a message here.