The most significant risks that could jeopardize the success of the project is getting the PID controller working. We recently had a major breakthrough in the calibration process and we have two axes currently working with our setup. We hope to have a hovering drone soon. Although this is behind schedule, we have the path planning code and the tracking code ready to use as soon as the hovering drone part is working. We are managing the risks by having absolutely everything else ready.
No major changes were made to the design of the system.