This "flying away from the needle" is also required when flying outbound on the localizer's front course. Unless the aircraft's Instrument Landing System (ILS) equipment includes reverse sensing capability, when flying inbound on the back course, it is necessary to steer the aircraft in the direction opposite the needle deflection when making corrections off-course to on-course. Some localizers may transmit the course line along the extended centerline of a runway, in the opposite direction to the front course, which is called the back course.The localizer's approach course, used with other functional parts (glide-slope, marker beacons, etc.), is called the front course.Instrumentation operates between 108 - 111.95 MHz on one of 40 channels that transmits from a ground node.The localizer (LOC) provides lateral course guidance during an approach to landing.Instrument Flying Handbook, Instrument Landing System.Guidance is provided through a ground based system that consists of several components.With a background in system function, pilots then perform an instrument landing procedure as published or via radar vectors.The system is not foolproof, however, and so pilots must be aware of the factors which can cause course distortion to ensure they are receiving reliable signals.These approaches all come with their unique set of minimums to provide a margin for error and safety buffer to compensate for potential limitations and malfunctions.Other approaches use the same equipment but are similar to localizers, such as Localizer Type Directional Aid Approaches and Simplified Directional Facility Approaches.Finally, to aid the transition, visual information is provided through the use of airport lighting.Distance Measuring Equipment, which is simplified via frequency pairing.
Localizer approach specific weather minimums are found on approach plates. Horizontal accuracy increases as distance between the aircraft and localizer decreases. At an angle of 35 degrees either side of runway centerline, the useful volume extends up to 10 NM.
Useable volume extends to 18 NM for a path up to 10 degrees either side of runway centerline.
The localizer system is placed about 1,000 feet from the far end of the approached runway. Localizers also exist in stand-alone instrument approach installations and are not always part of an ILS. It is then referred to as a Localizer Type Directional Aid. In some cases, a course projected by localizer is at an angle to the runway. It is not to be confused with a locator, although both are parts of aviation navigation systems. In aviation, a localizer is the component of an Instrument Landing System that provides runway centerline guidance to aircraft, but not the glideslope information. Freebase (0.00 / 0 votes) Rate this definition: