ultrasound

Could not find this when searching. I am getting a message stating "Ultrasound Failure; land as soon as possible" just after take off at about 10 to 15 feet. With this message, all bottom lights turn red. It responds normally, and when I bring it back to me at about 6 feet, the red lights turn...

Hi! I am planning to get me a phantom 4. Have had 5+hours on a phatom 3 and am really convinced. My main object for filming would be at work with huskies. I have been trying to search if its possible to turn off any ultrasound from the machine and I have got the idea that its related to the...