Flight Training Facts - Instrument Landing System

Do you ever wonder how a commercial jet makes a safe landing in the middle of a blinding rainstorm or in dense fog with zero or limited visibility? It is accomplished with an instrument landing system. Here is brief summary that was provided by Wikipedia.

It is important reading for any flight training student or flying enthusiast.

Instrument Landing System

An instrument landing system (ILS) is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument meteorological conditions (IMC), such as low ceilings or reduced visibility due to fog, rain, or blowing snow.

Marker Beacons

A marker beacon is a type of low frequency radio beacon used in conjunction with an instrument landing system that gives pilots a means to determine position along the runway. They are now gradually being phased out of service, especially in more developed parts of the world, as GPS and other technologies have made marker beacons increasingly obsolete.

Outer Marker

The purpose of this beacon is to provide height, distance and equipment functioning checks to aircraft on intermediate and final approach.

Middle Marker

The middle marker should be located so as to indicate, in low visibility conditions, the missed approach point, and the point that visual contact with the runway is imminent. Middle markers are no longer required in the United States so many of them are being discontinued.

Inner Marker

The inner marker, when installed, shall be located so as to indicate in low visibility conditions the imminence of arrival at the runway threshold.

History

Tests of the ILS system began in 1929, and the Civil Aeronautics Administration (CAA) authorized installation of the system in 1941 at six locations. The first landing of a scheduled U.S. passenger airliner using ILS was in 1938, when a plane flew from Washington, D.C. to Pittsburgh and landed in a snowstorm using only the instrument landing system. The first fully automatic landing using ILS was at Bedford Airport UK in March 1964.

There is much more information about this important subject. We will pass it along to flight training students in an upcoming article soon.