The MLS, or Microwave Landing System, was designed to eventually replace the ILS (Instrument Landing System) at large airports across the world. What it does is provide precision guidance (both lateral and verticle) to aircraft approaching a runway. It is VERY similar to the ILS which has widespread use across the world. Infact, one would not be incorrect to think of MLS as an upgraded, or expanded ILS. The key "selling points" for the MLS is the fact that it is much more accurate and precise than the original ILS. It has an operational frequency range from 5031 to 5091 MHz; 200 channels - more than enough for worldwide implementation. Its range is signifigantly greater than ILS, capable of lateral reception of +/- 60 degrees within 14 miles, and +/- 40 degrees outward towards 20 miles. Vertically, it is capable of reception at a 30 degree angle, all the way up to 20,000 feet, while still maintain a 3 degree glide path. All MLS would contain DME (Distance Measuring Equipment) to provide pilots with exact information as to how far out from the runway they really are. The Final high point of the MLS is what is called "Data Content" and "Auxiliary Data Content". When tuned to an operating MLS, pilots would be provided with the following information: Station ID, Ground Equipment and performance level, DME channel and status, 3-D location of MLS equipment, waypoint coordinates, runway conditions, and weather (RVR/Runway Visual Range, Cloud Ceiling, Altimeter setting, Wind, wake turbulence, wind shear). The MLS also has more sophisticated capabilities, such as curved and segmented approaches, selectable glidepath angles, and accurate 3-D positioning of aircraft in space. These will be implemented as aircraft begin to be better equipped with more advanced MLS instrumentation.