Published by FAA to replace previous 1981 guidance, Advisory Circular (AC) 91-57A reflects current laws governing hobby or recreational use of unmanned aircraft. Update details FAA Modernization and Reform Act of 2012's description of "model aircraft operation" and stresses model aircraft operators must comply with all Temporary Flight Restrictions, that they may not fly in any type of restricted airspace without prior authorization, and that they should be aware of Notices to Airmen.