If you're an AMA member, it is no longer a rule, guideline or even a nice suggestion. Email excerpt from AMA today: In this letter, dated July 7, 2016, the FAA states: "...model aircraft may be flow consistently with Section 336 and agency guidelines at altitudes above 400 feet when following a community-based organization's safety guidelines." "Community-based organizations, such as the Academy of Model Aeronautics, may establish altitude limitations in their safety guidelines that exceed the FAA's 400 AGL altitude recommendation." Essentially, this letter confirms that sailplanes, large model aircraft, turbines, and other disciplines can responsibly operate above 400 feet if the AMA member is operating within our safety programming. Equally important, the FAA again acknowledges AMA as a community-based organization.