The Ladder at the Kavala hostpital (the one with the helipad) has a few issues that I noticed when testing the bouncy wheel bug for the Ghosthawk.
While at the top of the ladder, the menu gives the option for going up the ladder.
While at the bottom of the ladder, the menu gives the option for going down the ladder.
While on the ladder, the w/s keys are reversed. Pressing w will bring you down the ladder, and pressing s will bring you up the ladder.
It seems as though the ladder is upside-down according to the game engine or something or other.