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the glide path indicated on two main instruments, and the oldest version of ILS-instruments was an instrument of its own used instead. This used two dangling bars, fixed in the middle of the top (localizer indicator) and in the middle of the left side (glide path indicator), and if the aircraft was located on the intended glide path, the dangling bars formed a cross. This is, in theory, however, more difficult to learn—but even for pilots experienced with using such indicators, it added another instrument they needed to focus on. With the indicators added to the artificial horizon (and to the compass), the pilot can theoretically watch the attitude simultaneously with the localizer and glide path.
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path was represented by a similar, but horizontal, dangling stick, fixed at one of the sides of the gauge. When the aircraft was located exactly at the ILS-beam (or glide path) the two sticks formed a cross. This interface resembles the flight director, which also forms a cross, but on the artificial horizon. This older ILS instrumentation system was omitted around the same time as jet airliners like
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located to the right of localizer beam and to the right if the aircraft is located to the left of the localizer beam. When the arrow is "united" to a straight line, then the aircraft is following the localizer beam. (This second "arrow-indicator" is omitted in modern cockpits, but the main compass is still located below the artificial horizon.)
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instruments. An older aircraft without an ILS receiver cannot take advantage of any ILS facilities at any runway, and much more importantly, the most modern aircraft have no use of their ILS instruments at runways which lack ILS facilities. In parts of Africa and Asia large airports may lack any kind
310:
The very first generation of localizer gauges had a different cockpit interface, and were not included in the artificial horizon nor any compass, but at a gauge of its own. The localizer was then represented as a dangling stick hanging from a fixed point at the top of a separate gauge, and the glide
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below the artificial horizon. The top and bottom of this arrow "is one unit", which shows current heading. But the middle part of this arrow is moving independently of the aircraft's heading. The middle of that arrow could be described as being "stand alone", and moves to the left if the aircraft is
167:
Localizer (LOC) and glide path (G/P) (a.k.a. glide slope ) carrier frequencies are paired so that the navigation radio automatically tunes the G/S frequency which corresponds to the selected LOC frequency. The LOC signal is in the 110 MHz range while the G/S signal is in the 330 MHz range.
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The cockpit ILS indicators are not to be confused with the flight director, which also places vertical and horizontal lines on the artificial horizon. A flight director only shows how the autopilot would fly. If the localizer dot (or arrow) indicate runway is to be found to the left, but the flight
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at least below 250 knots (for jet airliners), then by pushing a button marked "APP" or "ILS", then the autopilot presumably will turn and then follow the localizer. The autopilot will then also automatically descend according to the glide path. Normal procedure is to capture the localizer first and
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is set to the ILS frequency of that specific runway. If the transmitted localizer beam, which usually, but not always, is directed in the heading of the runway extension (exceptions exist, for instance, in
Innsbruck, Austria and in Macao). If the aircraft is located on this line, the localizer dot
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The glide path scale is located to the right of the attitude sphere. On aircraft which have a mechanical gyro compass are both the localizer and glide path indicated as a vertical and a horizontal arrow in the compass as well. But they are essentially read in the same way. On some aircraft is only
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The signals' phases at the antenna elements are arranged such that the 150 Hz signal is more prominent (has a greater depth of modulation) at a receiver located to the right of centerline, and the 90 Hz signal is more prominent to the left. The cockpit instrument uses the difference
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In modern cockpits, the localizer is seen as a colored dot (usually in the shape of a diamond) at the bottom of the artificial horizon. It does not appear during cruise, but comes up during the descent and approach to the selected runway, provided that the
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frequencies range between 108.10 MHz and 111.95 MHz (with the 100 kHz first decimal digit always odd, so 108.10, 108.15, 108.30, etc., are LOC frequencies and are not used for any other purpose).
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of transmitting ILS system. Some runways have ILS only in one direction; this can still be used for horizontal centering when landing the opposite direction (with lower precision) and is known as the
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In older cockpits, the localizer scale below the artificial horizon is rather short. But in older style cockpit instrumentation, the localizer also appears as an arrow in the
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the
Attitude Indicator, but is still a part of this instrument together with the glide path indicator and the cross in the center of the instrument which is called
258:. The localizer is shown on the scale below the attitude gauge, and is in this case looking almost as a small white "^" sign. Both the indicator and its scale are
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When the glide path is unserviceable, the localizer element can often be conducted as a separate non-precision approach; or a standalone
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then follow the glide path as well. If the angle is too large or the airspeed too high, capturing the localizer may be unsuccessful.
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between the modulation strengths of the two received signals to indicate left or right deviation from centerline.
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639:
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417:
ICAO Abbreviations and Codes (DOC 8400) (Report) (6th ed.). International Civil
Aviation Organization. 2004.
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ICAO Abbreviations and Codes (DOC 8400) (Report) (9th ed.). International Civil
Aviation Organization. 2016.
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director suggests a right turn, and the runway is not visible, then the pilot in command is having difficulties.
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engaged. The angle between the aircraft heading and localizer beam should be less than 30 degrees, and the
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signal is transmitted at one tenth of the power with a wider beam to prevent receivers from picking up the
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installation without an associated glide path, both are abbreviated as 'LOC' (or 'LLZ' prior to 2007.)
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A localizer (like a glide path) requires both a transmitting airport runway system and receiving
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on the localizer gauge scale in cockpit. The pilot then knows he or she must adjust the heading
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The localizer indicator is (on most aircraft manufactured from the late 1950s) shown
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will appear in the middle of the scale. But if the aircraft is located a little
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at 90 Hz, the other at 150 Hz. These are transmitted from co-located
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The expression "catch the localizer" refers to runway approaches with the
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antenna elements. Each antenna transmits a narrow beam. In addition, a
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218:. Statements consisting only of original research should be removed.
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112:(ILS) for the runway centerline when combined with the vertical
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Two signals are transmitted on one of 40 ILS channels. One is
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Satellite emergency position-indicating radiobeacon station
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prior to 2007), is a system of horizontal guidance in the
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648:Emergency position-indicating radiobeacon station
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30:"Localizer" redirects here. For other uses, see
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291:of the beam, the marker will appear to the
656:Standard frequency and time signal station
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234:Learn how and when to remove this message
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375:Difference in the depth of modulation
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74:instrument landing system localizer
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254:(AI), more commonly known as an
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108:is the lateral component of the
787:Aeronautical navigation systems
692:Instrument landing system (ILS)
640:Radio direction-finding station
502:and systems in accordance with
387:Simplified directional facility
807:Radio stations and systems ITU
624:Radionavigation mobile station
592:On-board communication station
540:High altitude platform station
441:. January 2008. Archived from
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381:Localizer type directional aid
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1:
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672:Ship's emergency transmitter
632:Radiolocation mobile station
628:Radionavigation land station
347:Limits of localizer coverage
116:, not to be confused with a
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214:the claims made and adding
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668:Experimental radio station
636:Radiolocation land station
620:Radiodetermination station
604:Aeronautical earth station
163:Carrier frequency pairings
52:runway 27, Mena, Arkansas)
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27:Horizontal guidance system
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572:Land mobile earth station
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110:instrument landing system
90:instrument landing system
60:Emission patterns of the
792:Aircraft landing systems
740:Emergency locator beacon
664:Radio astronomy station
612:Aircraft earth station
532:Survival craft station
432:"Frequency Allotments"
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100:Principle of operation
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504:ITU Radio Regulations
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732:Multi-satellite link
688:Radar beacon (racon)
644:Radio beacon station
616:Broadcasting station
600:Aeronautical station
548:Mobile earth station
339:Localizer at runways
180:Localizer in cockpit
580:Coast earth station
568:Land mobile station
520:Terrestrial station
353:instrument approach
141:amplitude modulated
44:as component of an
588:Ship earth station
564:Base earth station
556:Land earth station
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328:indicated airspeed
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256:artificial horizon
252:attitude indicator
199:possibly contains
155:of the main beam.
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797:Navigational aids
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724:Satellite network
319:were introduced.
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201:original research
16:(Redirected from
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802:Radio navigation
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608:Aircraft station
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284:navigation radio
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216:inline citations
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708:Radio altimeter
684:Secondary radar
660:Amateur station
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272:flight director
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104:In aviation, a
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728:Satellite link
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700:ILS glide path
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544:Mobile station
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500:Radio stations
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704:Marker beacon
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696:ILS localizer
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680:Primary radar
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576:Coast station
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536:Fixed station
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524:Earth station
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448:on 2010-08-28
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370:Andrew Alford
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197:This section
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716:Space system
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596:Port station
584:Ship station
560:Base station
552:Land station
450:. Retrieved
443:the original
439:NTIA.DOC.gov
438:
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304:gyro compass
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224:October 2016
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145:phased array
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76:, or simply
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32:Localization
736:Feeder link
134:back course
781:Categories
712:Radiosonde
452:2022-06-26
393:References
313:Boeing 707
208:improve it
153:side lobes
114:glide path
66:glide path
324:autopilot
299:the dot.
212:verifying
130:back beam
106:localizer
78:localizer
62:localizer
42:Localizer
18:Localizer
756:Category
365:AN/MRN-1
359:See also
149:clearing
512:desig-
297:towards
206:Please
173:carrier
125:cockpit
118:locator
68:signals
766:Portal
514:nation
94:runway
676:Radar
446:(PDF)
435:(PDF)
383:(LDA)
377:(DDM)
293:right
268:below
260:small
84:, or
317:DC 8
315:and
289:left
171:LOC
64:and
50:KMEZ
250:An
210:by
132:or
86:LLZ
82:LOC
72:An
46:ILS
783::
437:.
423:^
274:.
136:.
96:.
486:e
479:t
472:v
455:.
262:.
237:)
231:(
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222:(
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80:(
48:(
34:.
20:)
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