The nice sim framework Gazebo from here http://gazebosim.org/ can now be use from withing Paparazzi. Are you doing work on drones with Vision, Deeplearning thant check it out. I might make testing your new work so much simpler.
Installation and use take alook here http://docs.paparazziuav.org/v5.12/module__fdm_gazebo.html
Never forget... A sim is not reality... validate via testflights in the real world after you think everything you created works perfectly.