FSX Acceleration F-16 Viper Update. An update for FSX with Acceleration expansion pack of the F-16 Viper by Kirk Olsson (USVIPER.ZIP). The author has updated the flight dynamics so it will reach mach 2 at 40,000 feet. There is a problem with the panel side views that can be partially fixed by deleting the inglass.bmp file from the texture folder The view angle and the autopilot toggle of the panel have been changed as well. By Bob Chicilo.