An instrument approach system used in aviation. Short for Localiser and can also be used for the LNAV. Some planes may have APP which is a combination of the LOC function and the G/S (Glide Slope). APP is short for Approach. The LOC or ILS arms the G/S to the runway. Each runway at an airport typically has different ILS numbers (Set in your NAV 1 or 2 radio frequency), but some major airports have it in both directions such as KLAX. For missed approaches, use your BC (Back Course).
The LOC for KCLE Runway 24L is 111.55
by 737 California Air May 29, 2011