Originally Posted by phlpsfrnk

Eddie,
I believe that is a reference to FAA AC 91-57 dated June 9, 1981 which states in part;

c. Do not fly model aircraft higher than 400 feet above the surface. When flying aircraft within 3 miles of an airport, notify the airport operator or..."

http://www.modelaircraft.org/files/540-c.pdf

Please note the difference in punctuation which changes the meaning of the statements between the FAA document and the AMA safety code. Whenever there is an issue with models, FPV or otherwise the FAA points to AC 91-57 not the AMA safety code. The AC 91-57 is clearly mentioned in the Background discusion of the interpretation and was the basis for the wording in the interpretation of the special rule for model aircraft in section 336 of the FAA Modernization and Reform Act of 2012.

Frank