What are you talking about? The zoom feature works perfect, I've tried it on 3 different PCs now... It just locks up when you try to zoom the Deck Gun on the aircraft, but you shouldn't use Deck Gun on the aircraft, you have AA gun for that!
Oh well... You're the only one who seems to have that problem, I guess it's something with your PC, drivers, or there are some other MODs that prevent you from zooming...