Lost my V+ in a reservoir today. I'm trying to understand what went wrong. Firstly, I am an experienced pilot, hundreds of flights with no issues. The Phantom (this one was my third) is a P2V+ from last June, with the original motors and ESCs, no upgrades done. The only addition was a new Tx with the shoulder wheel which I got months ago and have been using with no issues. The phantom has never been crashed, is always hand caught so has never had a hard landing. I used it last Friday and it flew perfectly normally. This morning I drove up to a local reservoir to make a clip of it. I fired up in the usual order, TX, repeater, phantom, linked in the pc (to use reflector for screen recording) almost immediately I got 8 sats, so I took off. The normal procedure that I use is to hover about 10' up, check everything is ok and then go about filming. So I did this, but the aircraft started drifting around, and would not respond to the controls at all. I was using maximum sticks to keep it airborne. It flew off at about a 45 degree angle towards the ground but I managed to get it going up and it crossed a road and crash landed in a field. Thankfully, this being good old Ireland, it was a bog, and it got a soft landing. When it all started going wrong, I wasn't looking at the phone screen, using direct line of sight. When the phantom came down, I noticed that the screen said 'battery communication error' and so I believed that a dodgy battery might have been the cause. However, upon reviewing the reflector recording, I can see that this message only popped up on the screen upon impact, and the battery was partially ejected. Thinking about this a bit more logically here at home, the battery message wouldn't really have much relevance to lack of control, but in the field... So I changed battery (both are the larger, square pin type) and thought I'd have a second go, believing incorrectly that the battery error message was the issue. I got a gimbal warning message on screen, but this cleared and I took off again. Exactly the same thing happened again, the phantom took off at all sorts of angles, but this time it crash landed in the reservoir and is now lost for good. Why would this have happened? There can't be any interference coming from anywhere, it's in a mountain range in the middle of nowhere, there are no electricity pylons or anything else close by. I'm at a loss to understand what happened. Here are the two screen recordings; you can see I had loads of sats. Anyone able to help?