This happened last Sunday while filming the below video. I was not going to write about it but figured someone might learn from my mistakes. I programmed my flight mission with the Litchi App ahead of time. The weather on Sunday was dam near perfect so I head out on a 45 minute drive to Boathouse row in Philadelphia. I was positioned to the right of the lighthouse in a small clearing. I took off and flew one battery did get a good sense of how my run was going to be, I had time left so I did a 360 Pano and then landed. I put my second battery in, launched the Litchi App and flew to the starting position about a 1000ft a away. I started the mission and sat back and watched. Everything was going great, the phantom flew by me and everything looked great, then a guy came up to me and starting talking.........thats were the problem began I'm always very careful to have full control and know exactly where my drone is all the time. Back to my new friend, this guy was asking another question every 10 seconds, I have had this happened in the past and have always said I'll talk to you after I land. Not this time, my big mistake. Somewhere, sometime I lost orintation with my phantom, it could have been 30 seconds or two minutes. Then I saw it was directly across the river from me right over the expressway. Holy Sh%##$, how did it end up there, not only that buts it going down. In a panic I gave it full power, nothing happened......it would not respond to anything. I glanced down and I saw I still have a great signal and full GPS. How the hell can this be happening I thought? Left, right, up, down, forward and backwards.......nothing. I toggled back and forth, restarted the App but got nothing. Oh my god its getting lower and its going to land on the expressway (from my vantage point). I could see the headlines on the local news now. Dumb *** lands drone on Schuylkill expressway causing a pile up. I nearly broke the left stick pushing up to gain altitude but it did not respond..........then I heard those magic words. Maximum altitude reached!!!! How can that be I was thinking? Its 50 ft in the air not 400ft. Thats when I realized the drone I was trying to fly was NOT mine. In my loss of concentration from talking to my new friend I panicked . If only I had taken more than a split second to look at my screen I would have seen my drone was flying its correct path. Its no excuse but by then I could hardly see my screen because the sun glare was so bad, I quickly ran to the shade and saw the mission was over and my bird was at 400ft. I couldn't believe what I had done, how can anyone be so stupid. After landing my drone I began packing up, my hands were shaking......it gave me a really good scare. As I look back I know what mistakes I made and I'll never make them again. With over 500 flights with Phantom (the original) P2 and my P3P I have never seen another drone flying the same time and location I was flying. I'm not even sure what happened to the one I thought I was trying to fly.