Drone Manufacturer: 3DR
Drone Model: Solo
Country: United States of America
Type: Incident
Date: 2017-07-27
Applies: Daytime
Pilot Qualifications: Unknown Status
Pilot Flight Experience: Unknown Hours
Link to External Information About This submission: https://www.safecom.gov/safecom/17-0681
File Uploaded: None
Description
Unstable flight, loss of GPS, flip during landing caused by having 3DR Solo App running while also having Tower and/or Mission Planner running during flight. This problem has been noticed on at least two 3DR Solos, using two different tablets. This problem has been seen with both Mission Planner running on a PC laptop, and possibly with Tower running on the same tablet as the Solo App. Unstable flight, loss of GPS, and potentially unpredictable handling sometimes leading to flipping over during landing results from running these combinations of software. There are two scenarios where this has been observed: 1. As part of the regular pre-flight checklist, the Solo App was launched on the tablet to check Solo performance and RTL settings. Mission Planner was then launched on the PC laptop, and connected to the Solo simultaneous to the Solo App. A pre-planned mission was uploaded to the Solo from Mission Planner. Tower was launched on the tablet, connected to the Solo and the mission was downloaded to verify. The Solo App was at this point running in the background on the tablet. Tower has focus on the tablet, and Mission Planner was running and connected on the PC. The remaining items in the pre-flight checklist were followed and the PIC launched the Solo. The Solo immediately appeared twitchy in flight, and the PIC started to land the aircraft manually. GPS signal was then lost, and the Solo switched into FLY:MANUAL. The PIC was able to land the aircraft at the launch point and disarm without incident. The Solo was then powered off, re-powered, connected to Solo App and to Mission Planner, and a similar sequence was followed EXCEPT that the Solo App was killed {swipe right on Android tablet}. With only Tower running on the tablet and Mission Planner running on the PC, the Solo was launched, appeared stable with solid GPS fix, and an autonomous mission was conducted without further incident. 2. As part of the regular pre-flight checklist, the Solo App was launched on the tablet to check Solo performance and RTL settings. Mission Planner was then launched on the PC laptop, and connected to the Solo simultaneous to the Solo App. A pre-planned mission was uploaded to the Solo from Mission Planner. Tower was launched on the tablet, connected to the Solo and the mission was downloaded to verify. Mission Planner was then disconnected, and the PC laptop was shut down. At this point, the Solo App is running in the background on the tablet, and Tower has main focus on tablet. Mission Planner is not connected. The Solo was launched and immediately appeared twitchy in flight. The PIC attempted to land the aircraft. GPS was lost, then immediately regained. The PIC maintained positive control and landed the aircraft, and held the throttle down to disarm. Instead of disarming, the aircraft flipped over and the motors shut off after several seconds. All four props were damaged. The Solo was then powered off, props were replaced, re-powered, connected to Solo App and to Mission Planner, and a similar sequence was followed EXCEPT that the Solo App was killed {swipe right on Android tablet}. With only Tower running on the tablet, the Solo was launched, found to be stable with solid GPS fix, and several autonomous missions were then conducted without further incident. I suspect there is an interaction happening between Solo App and the other software packages, which leads to unstable flight characteristics and intermittent loss of GPS.
Reported Cause
Software issue leading to unstable flight. In all cases, this problem was solved by killing the Solo App before flying using other GCS software. Although Solo App is necessary for verifying Solo performance and RTL settings, it must be shut down before using the other software packages.