IAS Gyan

Daily News Analysis


18th January, 2024 Economy


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Picture Courtesy: www.pilotmall.com

Context: The Instrument Landing System (ILS) plays a crucial role in ensuring safe landings, especially during adverse weather conditions such as dense fog.


  • Instrument landing system (ILS) is a ground-based radio navigation system that provides horizontal and vertical guidance to an aircraft approaching a runway. It consists of two main components: a localizer and a glide slope.
  • An ILS is an essential tool for aviation safety and efficiency, especially in adverse weather conditions. It helps pilots land smoothly and accurately, reducing the risk of accidents and delays.


An ILS can have different categories depending on the accuracy and reliability of the system and the minimum visibility required for landing. The categories range from I to III, with III being the most precise and allowing for landing in zero visibility conditions. However, not all airports and aircraft are equipped or certified for all categories of ILS. Pilots must also undergo special training and follow strict procedures to use an ILS.

Key Points about ILS

  • ILS-equipped runways have ground-based transmitters positioned at the runway's end, emitting signals. Aircraft are equipped with onboard ILS receivers that pick up these signals.
  • As the aircraft approaches the runway, the pilot uses visual and audible cues provided by the ILS. Real-time adjustments are made based on these cues to keep the aircraft aligned with the desired glide path.
  • Category 3 (CAT III) is particularly significant, as it supports landing operations in low visibility conditions. CAT IIIB technology is utilized at airports like Delhi, Amritsar, Jaipur, Lucknow, and Kolkata in India.
  • ILS significantly enhances aviation safety and operational reliability by enabling precise landings even in challenging conditions. The technology aids pilots in executing precision landings when external visibility is severely compromised.


  • ILS operates as a crucial aid for pilots, providing both lateral and vertical guidance during the critical phases of approach and landing, ultimately ensuring safe landings even in conditions of low visibility caused by factors such as dense fog.


Q. Why is the Instrument Landing System (ILS) considered essential for aviation safety?

A) It controls the aircraft's speed

B) It enhances communication between air traffic control and pilots

C) It minimizes risks in low visibility conditions

D) It reduces fuel consumption during landings

Answer: C

Explanation: ILS significantly enhances aviation safety by providing precise guidance to pilots during critical phases of approach and landing, especially in conditions of reduced visibility like dense fog.