Originally Posted by
NorfolkSouthern
Can you be 100% sure that none of them could have been AMA members? As one other operator on this thread stated, he can see his glider when it's at a 3,000 foot altitude, and some of these pilots were complaining about drones being seen up to a mile away. They must be pretty big drones.
I was curious too, so I did a little math. 20/20 visual acuity means that an individual can resolve down to 1/60 of a degree of arc. That converts to 0.0002908882 radians. Since the angular distance between two points at a distance is equal to the distance away times the angle (in radians), this means that at one nautical mile, someone with 20/20 vision can resolve down to 1.77 feet. At two and three nautical miles, the resolution is 3.53 and 5.30 feet respectively. So it's entirely possible that an airline pilot could easily spot all but the smallest RC aircraft at considerable distances.