I learned the hard way tonight! Make sure you check every preflight that your phantom is in feet and not meters or vice versa if you use metric. I have no idea how mine changed but I flew this evening and thought I was at 400 feet I was at 400meters! AMOST 1400 FEET!!! It was evening so by lights you can't tell its that high and I was in full visual contact the whole time. I have no idea how the app changed or how I did it but there needs to be a double confirmation screen or something to do that. the only thing i did was turn my led off for a shot. I was dangerously high and feel terrible I always keep an eye out for aircraft and was in a safe flight zone none the less 1300 feet is way too high as a full size pilot as well it really hit home with me!! On a side note am I going to get a knock my door from the FAA ha ha, no seriously though? I did contact DJI support that they need to address this and I will always check before flights now!