Instrument Landing System(ILS)By: Steven StenstromGeorge Mason University
Instrument Landing System • History of IFR landing procedures before development if ILS • What’s it used for? • How it works • Why it’s so important • Future plans for ILS system
History of IFR Landing Procedures • Until the mid-1950’s, only visual landing procedures were possible • 1958-First IFR landing system developed • 1966-First ILS system developed and tested at Edwards AFB in Mojave, CA • 1968-First ILS applications installed at major airports • 1974-ILS systems mandated by FAA for at least two major runways at all Regional, and International Airports.
What It’s Used For • Aid aircraft to a runway touchdown point in IFR conditions • Aid larger aircraft (ex. Boeing 747,777) to land on a designated runway touchdown point(VFR, IFR) • Allow for use of new Autoland systems! MD-80 aircraft taking off over Glide-Slope equipment
How does it work? • VHF Frequency transmits radar signal and intensity data to ILS Signal Deciphering and Display Computer • Localizer signal transmitted in direction opposite of runway to horizontally guide aircraft to touchdown point • Glide-Slope signal transmitted at an angle of 7.5-10 degrees into sky to define vertical descent path to runway touchdown point • On-board antenna system located in aircraft radome receives radar and VHF signals and sends it to on-board ILS computer • Signal data is then displayed on instrument panel gauge which maps the directional, and descent path to the runway On-board ILS gauge from a Boeing 747-400 aircraft