Quick flight in the A400M from/to KLAX and buzzing downtown LA showed the same performance as the SU2 beta .14 & .18 builds (as expected).
On my PC, with my “standard” custom settings, I get around 50 FPS + / - (par for the course at airports like KLAX with AI traffic) and no stutters. Pics with the Dev-mode FPS widget enabled that show the FPS at different segments of the flight is here: