3DR Solo – Accident – 2018-06-19

Drone Manufacturer: 3DR
Drone Model: Solo
Country: United States of America
Type: Accident
Date: 2018-06-19
Applies: Daytime
Pilot Qualifications: Unknown Status
Pilot Flight Experience: Unknown Hours
Link to External Information About This submission: https://www.safecom.gov/safecom/18-0682
File Uploaded: None


We were flying an automated survey with a Solo mounted with a Ricoh camera, operating with Tower. Shortly after takeoff, lost GPS. Switched to fly manual. Attempted to return Solo to launch area and land manually, but was unable to regain full control of the aircraft. Attempted to land aircraft immediately at its current location by pulling back on left stick but Solo was not responsive. Aircraft flew off and crashed horizontally into grove of trees, damaging Solo. Had completed Solo level and compass calibrations on site less than an hour before. Flew another Solo on site that morning without problem. Study area was relatively flat, mostly forested with small lakes and wetlands. Launch area was grassy area over buried oil pipelines with clear view of sky. This was the second flight with this Solo at that location that day. Weather was hot {81F} and cloudy, with little to no wind {{5mph}. DOI launch checklists had been followed. Notified MISHAP line and USGS National UAS Project Office. Provided USGS NUPO with aircraft, controller, and tablet logs for review. Joe Adams analyzed Solo dataflash logs and determined there was an EKF failure causing the loss of control. See attached Mission Planner tlog playback screen. Not sure exact cause of EKF failure but tlog playback also shows “PreArm: Check mag field?” which usually means compass confusion.

Reported Cause

Loss of control and compass error.