Over the weekend I flew a standard survey mission. About four or five minutes into the flight, I got a "no.4 motor failure" error and then a "vehicle will return to take off area". This did not happen. Instead, the drone literally dropped out of the sky. There is damage to both the drone and the E90. Interestingly, none pf the props were damaged which surprises me greatly. I had the altitude set at 100' as the area being surveyed is treed. I am having trouble contacting Yuneec as their phone number just gets a busy signal and I don't have an email to send to other than the submission form on their website. I purchased this drone directly from Yuneec US website. Any advice appreciated.