Hi Youen - had a quick look at your mod with visual studio - it's not working in 1.0.5 because ModuleLiftingSurface.SetupCoefficients() no longer takes the air density as a parameter. If you change line 255 in Trajectories.StockAeroUtil FROM: wing.SetupCoefficients(v_wrld_vel, rho, out nVel, out liftVector, out liftdot, out absdot); TO : wing.SetupCoefficients(v_wrld_vel, out nVel, out liftVector, out liftdot, out absdot); It'll work. I tried building the mod and running it, and it worked for me! Hope that helps you