The vBulletin search function could return a myriad of confusing hits if you use more than one search word. So use single words but browse around for possibly related search words. In advanced search, it is fairly useful if you have an approximate idea of at least one member who posted in a thread or if you want returns sorted either as threads or posts. I still use it for 2/3d's of my searches.
The google searches on this site can give general results but at least you can search multiple words or (by surrounding in quotes) "an exact phrase." See http://www.airforums.com/forums/show...9&postcount=20
It never hurts to ask, "Does anybody know where...?" Especially if the search king, 2airishuman, is online.