3DR Solo – Accident – 2017-09-21

Drone Manufacturer: 3DR
Drone Model: Solo
Country: United States of America
Type: Accident
Date: 2017-09-21
Applies: Daytime
Pilot Qualifications: Unknown Status
Pilot Flight Experience: Unknown Hours
Link to External Information About This submission: https://www.safecom.gov/safecom/17-0978
File Uploaded: None


On September 21st UA475 was being used to inspect a reclamation site where alternative access had been limited. At take-off I reported to the visual observer that the UAS battery was at 93{{%}}. This was a little low, but seemed reasonable since the UAS had sat powered on while going through the pre-flight checklist. From take-off I moved the UAS 1400 feet out from my location and immediately received a vibration from the controller that the UAS battery was at 25{{%}} life. I started to bring UA475 back to the launch site and was notified that connection between the controller and UA475 had been lost. At that same time UA475 attempted to land autonomously because of its critical level of battery life. After a short search, UA475 was recovered at the bottom of a shallow draw upside down. The unit had sustained broken props and some scratches to the exterior. After replacing the props I initiated a test flight and during the boot up process it indicated that a level sensor needed re-calibrated. Re-calibration was attempted several times unsuccessfully. I researched the issue online and found a posting suggesting that the sensor was stuck and that a firm smack to the bottom of the unit could be a fix. I tried the suggestion and it worked. I performed another test flight and UA475 was back to full functionality. I tested the suspect battery at a low hover and experienced the same rapid depletion of batter life. The battery had 15-20 charge and discharge cycles to date.

Reported Cause

Loss of power.