A lot of Luis Castro's textures have a missing alpha channel in the TDS727_JT8D-9_T.bmp file, but TDS727_JT8D-217_T.bmp does have an alpha channel. Put model=217 in aircraft.cfg to use the 217 texture. If you've got a graphics editor that can handle alpha, the 9 texture can be fixed by copying the alpha from the 217 texture.
The G limits were set to 0 in aircraft.cfg. This caused an Aircraft Overstressed to be triggered after loading when Crash Detection was turned on. To fix this, I made the G limits to be the same as the limits in polikarpov_u-2_ski.zip: positive_g_limit_flaps_up=5 positive_g_limit_flaps_down=4 negative_g_limit_flaps_up=4 negative_g_limit_flaps_down=3 load_safety_factor=1.5 A nicely modeled aircraft with attention to small details.