"Mods/aircraft/Flaming Cliffs/entry.lua" change line 128:
make_flyable('Su-27' , current_mod_path..'/Cockpit/KneeboardLeft/', {self_ID,'Su27',old = true}, current_mod_path..'/Comm/Su-27.lua')
Change "old = true" to "old = 6". Not sure if that will work 100% but that should give it the cockpit.