Quick back story. I had owned the P3A for about 2 weeks prior to taking it with me on vacation to the White Mountains in NH. I had flown my P3S on several Litchi missions before this and purchased the A as an upgrade for the trip. I upgraded the firmware on the AC, Controller as well as all 3 batteries. I am running the latest IOS software as well as the latest Litchi. I flew several manual missions out to about 1500' and 2-300 feet altitude with no issues. The day before I flew the mission I noticed I had one episode where it kept saying disconnected randomly even though the controller was next to the P3A on the ground. I powered everything down. Powered it back up, did an IMU cal on a perfectly level surface and a compass cal and everything seemed fine after that. I built a Litchi mission that was approx 2 miles in total length with the AC being 2300' away at its farthest point and 300' AGL. I loaded the mission with no issues. Initiated a takeoff, started the mission and all was going well till the AC was about 2100' out. At this point I instantly lost both video feed as well as it saying AC disconnected, even though it showed the radio at 47% signal strength. Video feed was zero. I lost all data from the AC. Although the AC was OOS just beyond the pines I quicklly flipped the controller on and off hoping to connect again. Nothing. It was a 10 minute mission so I waited, hoping it would return in about the 6 minutes it had left. After 30 minutes of waiting and my wife cursing at me I gave up hope. I spent the next 9 hours driving and hiking hoping for any sign of it. I hoped it had gone down where someone might find it and call me as it has a sticker with my FAA Number as well as my cell number. So far nothing. I am devastated. ANY idea what may have caused this? Any way to find out or retrieve the logs? After I returned home this past saturday I have been consumed with reading to see if I could figure out what happened. Being honest I am concerned about ordering another as the fly away issue seems fairly prevalent with the DJi's. Perhaps I should make the move to an Autel and sell off the extra Phantom equipment I have.