Hmmm. The Mi-28 has an external flight information MFD as does the Mi-24 which I added. I did use the AVCKPT_DISPLAY_LHS_MFD for the external MFD display for cockpits, but I just used it, I didn't set it up or close it down.
The Mi-28 and Mi-24 flight_texture_screen which uses that texture are both created and destroyed correctly when you select or shut down the helo normally. I wonder if Ctrl-X bypasses the deinitialize functions. I've never looked at that command's code before. Does anyone know where it's located in the code? I wonder if that command is somehow helicopter specific. It shouldn't be.
I never shut the program down that way myself, I always exit through the menus.