You're a victim of what I like to call "Collision Detection Failure", which doesn't seem to exist in multiplayer like it does in single player. This is one of the reasons that I still haven't beaten Chinese Mission #2! I can't afford to stay and stare at the Hangar while repairing it! I've got stuff to do!

This seriously ticks me off, and I've practically given up on beating the Chinese Campaign because of this bug. It's too much to be forced to stare at stuff during upgrade/repair/reload in a hectic/difficult mission.