AC 91-57
FAA advisory circular for recreational unmanned aircraft operations.
AC 91-57 is an FAA Advisory Circular that provides interim safety guidance to individuals operating unmanned aircraft, including flying model aircraft, for recreational purposes in the National Airspace System of the United States. It is notable as the FAA's early formal recognition of safety issues raised by recreational RC model aircraft operations, originally published in 1981 under the title Model Aircraft Operating Standards.
Quick Facts
- Title
- Exception for Limited Recreational Operations of Unmanned Aircraft
- Year Started
- 1981
- Version
- C
- Versiondate
- 2022 October 20
- Organization
- Federal Aviation Administration AFS-800
- Abbreviation
- AC 91-57
- Domain
- Aviation safety, / Regulation of UAVs in the United States
Facts from the source article.
Lore & Background
In 1981, the FAA published AC 91-57, then entitled Model Aircraft Operating Standards, to address safety concerns arising from the recreational operation of RC model aircraft. The circular conveys the FAA's expectation that operators exercise good judgment so that persons on the ground or other aircraft in flight are not endangered. It includes guidance on site selection, advising users to avoid noise-sensitive areas such as parks, schools, hospitals, and churches. Hobbyists are also advised not to fly in the vicinity of spectators until the model aircraft has been flight tested and proven airworthy. The circular specifies that model aircraft should be flown below 400 feet above the surface to avoid other aircraft in flight, and the FAA expects operators to maintain visual line-of-sight at all times.
Reader's Guide
AC 91-57 holds significance as the FAA's foundational guidance for recreational unmanned aircraft operations, establishing key safety parameters that have influenced later regulations. Its legacy includes the altitude limit of 400 feet and the visual line-of-sight requirement, which remain central to recreational drone operation. The circular also introduced the concept of avoiding noise-sensitive locations, reflecting early awareness of community impact. Notably, the FAA has clarified that AC 91-57 applies exclusively to modelers and specifically excludes its use by persons or companies for business purposes, despite some commercial operators having mistakenly used it as a basis for commercial flight operations. This distinction underscores the circular's role as a recreational-only framework within the broader regulatory landscape. The circular continues to be referenced in later FAA policy, including its updated version AC 91-57C issued in October 2022, which carries the title Exception for Limited Recreational Operations of Unmanned Aircraft.
Frequently Asked Questions
What is FAA Advisory Circular AC 91-57?
AC 91-57 is the FAA's interim safety guidance document covering recreational unmanned aircraft and model aircraft operations within the United States National Airspace System. It was originally issued in 1981 under the title "Model Aircraft Operating Standards" and remains a key reference for hobbyist pilots.
What altitude limit does AC 91-57 set for recreational model aircraft?
The circular requires that recreational model aircraft be operated below 400 feet above the surface. This ceiling is one of the core operational boundaries the FAA established for hobbyist flights.
Who does AC 91-57 apply to?
It is written specifically for individuals flying model aircraft for recreational purposes, not for commercial or part 107 remote pilots. The guidance targets the hobby community operating within the NAS.
Does AC 91-57 require the pilot to keep visual line-of-sight with the aircraft?
Yes, the circular mandates that the operator maintain unaided visual line-of-sight throughout the entire flight. This VLOS rule is a central safety condition in the document's operating standards.
Why is AC 91-57 considered important in RC model aviation history?
It marked the FAA's first formal acknowledgment that recreational RC model aircraft posed distinct safety considerations within shared airspace. Published in 1981, it gave the hobby community an official regulatory touchstone for safe operations long before modern drone rules were written.
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