5000 meters or 3.1 miles it shows it can be done. The flight operator said it required he fly the P4 back in Sport mode and not use RTH. He said the aircraft used 28% battery traveling 15mph on the way out, and in Sport mode Full throttle coming back only used 18% battery. Roughly around the 1/2 point of the video a text message appears in the vid mentioning he is Pushing Through the Weak Transmission Signal the aircraft displays as it is searching for a better Channel and/or bitrate setting. I believe what is trying to be conveyed here is to make your flights with the channel feature in auto mode, and not manual. So...I must point out to those of you that might be some what new to the scene, this flight takes place in an area where there is NO interference. Flying in the city or suburbs your aircraft will most likely not fly such distances. I also would like to point out to all who views this thread to take it for what it's worth. This is not my flight. I would have given more visual proof with anything I was making a claim to. The person that posted this video may have used other means to improve the flight? We don't know because we are not shown video of the operators side of the flight. *I found the video posted on dji.com website.