Prior to a recent vacation, I was hovering my Phantom 2 Vision + in the front yard to discharge the batteries. I had no intention of flying, so I did not put prop guards on the Phantom. As is usually the case, my poor judgement got the better of me. I put the bird into atti mode and took off toward the neighbors driveway, 2-3 blocks down. Bird lost altitude when I gave it the forward. I caught the neighbors trash can and the bird crashed and flipped over onto the pavement. I put the bird away, as it was late and I figured I would see how it went when the trip was over. Props were dinged up pretty good, nicked and such. I knew they were garbage. Came back to the States on 03/03/15. Been raining and windy and cold here for most of the last 3 weeks. I just had time to take her out Wednesday 03/18/15. I had to calibrate the compass multiple times. The app told me calibration was needed. I have never seen this before. Took a couple of times to calibrate. Other than that, it seemed to power up fine. I had the prop guards on this time. Good thing. As soon as I got about 3 feet off the ground, as I was giving it good throttle, the bird just flipped over and crashed. There was no wind, and had 10 GPS satellites upon takeoff. I checked everything external, and everything seemed ok. I chalked it up to a fluke and tried again. I got her into the air this time, but engines making noise, like they are fighting to maintain position in a good wind, but there was no wind. Very calm. GPS positioning was all over the place. I guesstimate a 20' circle was as good a hover as the bird could do, with no control input from myself. Bird won't fly in a straight line either. Pulls hard to the right (I think) Everything appears to be level, but without a micrometer, I suppose one of the motors might be out of align. ETA The Phantom also will not accept inputs from both sticks simultaneously. If I input forward and ascent at the same time, then it will only go forward. It will not ascend until I let off the forward input. It also seems to be stuck in atti mode. If I input forward, it will lose altitude as it goes forward. I have not opened the bird to check yet. Is there anyplace I should start troubleshooting first, or is this something that I should leave to the pros? Just to let you know my skill set....I am a former network engineer. I was a civilian contractor with the Air Force, and installed ATM and GigEthernet on bases. I went through the Electronics Technology program at my local JR College 20+ years ago, and can solder and troubleshoot down to the component level (on 20 year old stuff anyway lol) Thanks Patrick ETA 03-21-15 Advanced IMU calibration is done. Also upgraded all the firmware to the latest versions. Of course there is about 9 inches of rain coming to this little portion of Texas, so it's going to take a while to determine if this will help or not. ETA 03-23-15 After upgrading to latest firmware, and advanced IMU calibration, I thought my issues were solved. Took off well, flew ok. Very light wind. flew for about 10 minutes, before the drizzling rain started back up. I go to land and that's when the problem re-appeared. I always hand catch when landing. I was reaching forward to catch the craft, and it was like I hit both sticks on the controller in opposite directions. It was hovering about shoulder high. I was careful to not have my hands anywhere near the control sticks. All of a sudden, it almost took my fingers off. It jumped forward like I had given full forward input, and at the same time, it dove into the ground. Also, i noticed that the prop guards were always in the FPV display. I have it in NAZA mode, but both switches are in the up position. GPS and IOC OFF respectively. But the angles when given throttle are like ATTI mode. And altitude isn't really controlled anymore. Hovering 40 feet in the air, I noticed it would fall 5-10 feet with no input from me. Just hovering. This was with 8 GPS sats locked. I also noticed a strange thrumming noise when bird is flying. I can't really describe it, but it sounds different than before. I know that's not much help. Also, unfortunately, I did not have video running.