Hi viper, if you have addons 1 or 2 (starflight), pls install patch 1.9.7.11 http://www.aerofly.com/www/downloads.html

If you have addons 3 and 4, pls install patch 1.11.7.9. This patch introduces quite a few changes and requires at least OpenGL 2.0. Please only install this patch if you have a 3D-card with OpenGL 2.0 driver support. Do NOT use this patch on 3D-cards older than a NVIDIA GeForce 7000 series or on ATI cards older or slower than the X800 series. We also recommend a minimum of 128 MB of 3D graphics card memory.