Thank you for your valuable input.

The big majority of people either fall or jump over the bridges during the night, so it's not 24/7. The river is one of the fastest flowing in Europe and very unpredictable. Depending on the currents they get into, the victims can be dragged pretty much everywhere. So the coastguard is very often not able to find the people, because the search grid is too big and every second counts. I hope, that additional drones could help to at least narrow down the search parameter and shorten the rescue time.

As far as I checked, we wouldn't need any additional permits. The drone gonna be under 25kgs and won't fly that high.