In response to my last safety article on 3-D vision and depth perception, Jim Rice, retiring District VIII vice president and Safety Committee Chairman, sent me some good information that I will pass on to you. Jim commented on the thoughts I had about keeping "blue sky" between you and other airplanes in your flying space. He pointed out that this same advice has just been added to an AMA document concerning RC airplanes and full-scale aircraft.  His message:
     "Ironic that you would describe a way to keep separation between aircraft in the same week that we added a paragraph to PDF 540-D that tells them the same thing ... only with different words. The FAA work group has been using the term ‘Blue Sky’ for about three years and the FAA seemed to like the concept."
   

      AMA document 540-D provides guidelines for RC operations in the NAS (National Airspace System). As Jim pointed out, there is a new advisory in that document that recommends using ‘"Blue Sky" between you and full-scale aircraft to avoid depth perception mistakes. Here’s an excerpt:
     "Blue Sky" is a term used to explain the method used to increase separation between a model and a manned aircraft in the same vicinity. The modeler should maneuver the aircraft in such a way as to increase the amount of blue sky perceived between the model and the manned aircraft. By increasing the blue sky separation, the question about depth perception is taken out of the equation and the modeler need not worry whether the model is closer to him than the manned aircraft or further away. Increasing the blue sky between the model and the manned aircraft automatically increases separation between them.

     Thanks Jim, for that great follow up to my last article. When I pulled up the document and read it in its entirety, I thought that the rest of the information should be brought to your attention as well. These guidelines are great safety rules to follow, not only for operations with full-scale aircraft in the vicinity, but for flying in general. You might want to bring the document along to your next meeting or post it on your website. Here’s a link: www.modelaircraft.org/files/540-D.pdf