Flying the ILS can be a mysterious and complex maneuver; however, it is the most used landing tool in the airliners arsenal. Particularly where lowVis approaches are flown, it is the ILS that makes the whole Air Traffic Control system operate. Without the ILS, the ATC system would grind to an halt; and yet few pilots know of the complexity and difficulty in operating in the CAT III approach environment. It is all revealed here in this article.