The Charity
Aviation
Maritime
From AAIB report No AAIB-29203. A swarm of 638 UAs took off as part of a planned test of a light display. The preprogramed launch and animation flight were completed without incident. As the UAs switched to ‘return to home’ mode they returned to their grid positions. Several UAs then flew out of formation, before the pilot sent an emergency hold command to which the fleet responded, and all UAs held their position. A manual ‘return to home’ command was sent and the UAs returned to their grid formation. When the swarm began to descend the same UAs again flew out of formation. The swarm was then landed in altitude order, due to concerns about battery endurance. All UAs stayed within the planned geofence. Three UAs sustained broken arms and there were several chipped propellers. An investigation by the operator determined that deviations from the planned flight route were caused by flat batteries in the controller unit, which had been left switched on when stored.
Lessons learned: The Operator has introduced a new procedure to remove all batteries when not in use.
We agree with the initiative to remove all batteries when they are not in use. We would also suggest that if it isn’t already there, it would be a good idea to add a controller battery check as part of the pre-flight checks. Whilst we do not have a significant amount of experience with swarms, we have set out below a few basic recommendations that readers may wish to consider when operating a swarm:
With swarm light shows becoming more frequent, these provisions are designed to manage some of the potential pitfalls of flying swarms.
Finally, it is worth highlighting that this occurrence is in some respects a good news story. In dealing with the issues that occurred, everything that was supposed to happen did and the UA stayed within the geofence.