ILS system which is defined as Instrumental Landing System is a system that allows the aircraft to be landed safely by the aid of electronic devices horizontally and vertically. This system allows aircraft to be landed safely in the conditions that low visibility such as low cloud ceiling, vision is restricted, foggy, rainy, snowy and in cases where visibility is high in addition to being safe also allovvs to be landed safely.

The main function of the ILS system is, ensuring the pilot to see the runway by landing the aircraft to the ground safely in the poor weather conditions. ILS helps the pilot to be able to see the runway more clearly by getting closer to the ground compare with the other navigation systems (VOR, NDB) and pilot can perform the landing by the aid of other electronic systems of the aircraft and visual aids on the runway (approaching lights ete).