Transcript Instrument Landing Systems

Instrument Landing Systems
Instruments and Avionics
Blake Crosby
What Is An Instrument Landing System?
The ILS is designed to provide an aircraft with a precision final
approach with horizontal and vertical guidance to the runway. The
ground equipment consists of a localizer, a glide path transmitter
and an NDB along the approach path. A DME fix may replace the
NDB.
7/17/2015
Instrument Landing Systems
2
Why?
 Scheduled service would be impossible
without a way to land in poor weather.
 Provide a standard way to land and take
off from any airport in the world.
 Additional safety and situational
awareness.
7/17/2015
Instrument Landing Systems
3
History

Tests of the first ILS began in 1929

The first scheduled passenger airliner to land using ILS was in
1938. A Pennsylvania-Central Airlines Boeing 247-D from
Washington to Pittsburgh.

In 1949, ICAO adapted an ILS standard developed by the US
Army as a standard system for all of its member countries.
7/17/2015
Instrument Landing Systems
4
7/17/2015
Instrument Landing Systems
5
7/17/2015
Instrument Landing Systems
6
7/17/2015
Instrument Landing Systems
7
How It Works
 Glideslope
 Provides vertical navigation
 Localizer
 Provides horizontal navigation
 NDB/ADF or DME
 Provides distance from runway
7/17/2015
Instrument Landing Systems
8
How It Works
Localizer
Antenna is located on the
opposite end of the
runway.
Glideslope
Antenna is located on one
side of the runway at
approx. touch down point.
7/17/2015
Instrument Landing Systems
9
Glideslope Antenna Array
7/17/2015
Instrument Landing Systems
10
Localizer Antenna Array
7/17/2015
Instrument Landing Systems
11
NDB Antenna
7/17/2015
Instrument Landing Systems
12
Course Deviation Indicator
Signal Integrity Flag
Indicates if instrument is
unreliable
Glideslope
Deviation from
optimal glide path
7/17/2015
Localizer
Deviation from
runway centre line
“Dots”
Each “dot” on the
instrument represents 2°
of deviation
Instrument Landing Systems
13
Limitations of current ILS
 Localizer is sensitive to obstructions
like buildings and terrain.
 Glideslope errors can occur if terrain
is sloping or is uneven infront of the
antenna.
 Since antennas point in a single
direction, only “straight” approaches
are available.
 Can be costly.
7/17/2015
Instrument Landing Systems
14
Other types of ILS
 Microwave Landing System
 Curved approaches are possible
 Less interference and more accurate than
traditional ILS
 Used mostly in Europe
 Being replaced by GPS approaches
 Transponder Landing System




7/17/2015
Easy and quick to deploy in remote locations
Only one airplane can use the system at a time.
No additional equipment needed on aircraft.
Similar system used by the military.
Instrument Landing Systems
15
Videos
http://www.youtube.com/watch?v=M3wnl1Ut--o
http://www.youtube.com/watch?v=ZnEtr6Ei1sc
7/17/2015
Instrument Landing Systems
16