LOC vs ILS

The main difference between a localizer (LOC) and an instrument landing system (ILS) is that the LOC provides lateral guidance, while the ILS provides both lateral and vertical guidance:

LOC

A system that provides azimuth guidance to aircraft along the runway axis. LOCs transmit VHF signals between 108.1 MHz and 111.95 MHz. LOCs can be sensitive to obstructions in the signal broadcast area, such as large buildings or hangars.

ILS

A precision runway approach aid that uses two radio beams to provide pilots with both vertical and horizontal guidance. The ILS consists of a localizer and a glideslope, which provide lateral and vertical guidance, respectively. ILS approaches can allow pilots to land in poor visibility conditions, such as low cloud ceilings and short visibility.

The choice of approach depends on the specific conditions and requirements of the flight. Pilots should always be aware of the minimums for each approach, which can be found on the approach plates.