{"id":14526,"date":"2025-06-07T16:32:01","date_gmt":"2025-06-07T11:02:01","guid":{"rendered":"https:\/\/ibexaviation.com\/pilot-training\/?p=14526"},"modified":"2026-07-26T09:56:15","modified_gmt":"2026-07-26T04:26:15","slug":"microwave-landing-system","status":"publish","type":"post","link":"https:\/\/ibexaviation.com\/pilot-training\/microwave-landing-system\/","title":{"rendered":"Microwave Landing System (MLS)"},"content":{"rendered":"<p> <img decoding=\"async\" src=\"https:\/\/ibexaviation.com\/page-show\/radio-navigation\/r9-microwave-landing-system-1.jpg\" alt=\"\" loading=\"lazy\"\/><\/p>\n<h2>Microwave Landing System (MLS)<\/h2>\n<p>ILS (Instrument Landing System) uses radio beams to provide fixed landing guidance, while MLS (Microwave Landing System) uses microwave signals for more flexible guidance. ILS has limited approach paths, whereas MLS supports wider approach angles and curved approaches. MLS offers greater accuracy and is less affected by terrain and signal interference than ILS.<\/p>\n<h3>Introduction to MLS<\/h3>\n<p> <img decoding=\"async\" src=\"https:\/\/ibexaviation.com\/page-show\/radio-navigation\/r9-microwave-landing-system-2.jpg\" alt=\"\" loading=\"lazy\"\/><\/p>\n<ul>\n<li>The <strong>Microwave Landing System (MLS)<\/strong> consists of five integrated subsystems.<\/li>\n<li><strong>Azimuth Guidance<\/strong> \u2013 Located beyond the stop end of the runway to provide lateral guidance.<\/li>\n<li><strong>Elevation Guidance<\/strong> \u2013 Located on one side of the runway to provide vertical guidance.<\/li>\n<li><strong>Distance Measuring Equipment (DME)<\/strong> \u2013 Co-located with the azimuth equipment to provide distance information.<\/li>\n<li><strong>Missed Approach Guidance<\/strong> \u2013 Located ahead of the runway threshold to guide aircraft during missed approaches.<\/li>\n<li><strong>Flare Guidance Subsystem<\/strong> \u2013 Assists aircraft during the flare and touchdown phase.<\/li>\n<li>MLS operates in the <strong>5031.0 MHz to 5090.7 MHz<\/strong> frequency band (SHF).<\/li>\n<li>The emission designator is <strong>N0X<\/strong>, indicating a modulated carrier with digital data transmission.<\/li>\n<\/ul>\n<h3>Advantages of MLS<\/h3>\n<p> <img decoding=\"async\" src=\"https:\/\/ibexaviation.com\/page-show\/radio-navigation\/r9-microwave-landing-system-3.jpg\" alt=\"\" loading=\"lazy\"\/><\/p>\n<ul>\n<li>Can be installed in mountainous or uneven terrain due to minimal site errors.<\/li>\n<li>Unaffected by interference from civilian FM radio broadcasts.<\/li>\n<li>Provides up to <strong>200 operating channels<\/strong> in the SHF band.<\/li>\n<li>Supports flexible approach paths, reducing arrival delays.<\/li>\n<li>More economical to install because DME is integrated with the system.<\/li>\n<li>Flexible glide paths accommodate all aircraft types, including helicopters.<\/li>\n<li>Can transmit supplementary information such as weather and runway conditions.<\/li>\n<\/ul>\n<h3>Principle of MLS<\/h3>\n<p> <img decoding=\"async\" src=\"https:\/\/ibexaviation.com\/page-show\/radio-navigation\/r9-microwave-landing-system-4.jpg\" alt=\"\" loading=\"lazy\"\/><\/p>\n<ul>\n<li>MLS operates using the <strong>Time Referenced Scanning Beam (TRSB)<\/strong> principle.<\/li>\n<li>The <strong>Azimuth Scanning Beam<\/strong> scans from left to right at approximately <strong>13.5 scans per second<\/strong>.<\/li>\n<li>The <strong>Elevation Scanning Beam<\/strong> scans from top to bottom at approximately <strong>40.5 scans per second<\/strong>.<\/li>\n<li>Azimuth and Elevation scans determine the aircraft&#8217;s horizontal and vertical position.<\/li>\n<li>The aircraft calculates its position by measuring the time difference between the <strong>TO<\/strong> and <strong>FROM<\/strong> scanning beams.<\/li>\n<li>MLS uses <strong>Time Division Multiplexing (TDM)<\/strong> to allow all subsystems to share the same frequency.<\/li>\n<li>Distance from the runway threshold is provided by a frequency-paired precision DME.<\/li>\n<\/ul>\n<h3>Coverage of MLS<\/h3>\n<p> <img decoding=\"async\" src=\"https:\/\/ibexaviation.com\/page-show\/radio-navigation\/r9-microwave-landing-system-5.jpg\" alt=\"\" loading=\"lazy\"\/><\/p>\n<ul>\n<li>Forward coverage extends up to <strong>20 NM<\/strong> and <strong>20,000 ft<\/strong>.<\/li>\n<li>Azimuth coverage extends up to <strong>40\u00b0<\/strong> on either side of the runway centreline.<\/li>\n<li>Elevation coverage ranges from <strong>0.9\u00b0 to 20\u00b0<\/strong> above the horizontal.<\/li>\n<li>Offset approaches can provide guidance even when the aircraft is approximately <strong>2 NM<\/strong> from touchdown.<\/li>\n<li>Back beam coverage extends up to <strong>10 NM<\/strong> and <strong>10,000 ft<\/strong>.<\/li>\n<li>Back beam azimuth coverage extends up to <strong>20\u00b0<\/strong> on either side of the runway.<\/li>\n<li>Back beam elevation coverage ranges from <strong>0.9\u00b0 to 15\u00b0<\/strong> above the horizontal.<\/li>\n<li>Back beam guidance may be used for missed approaches and departures.<\/li>\n<\/ul>\n<h3>Accuracy of MLS<\/h3>\n<p> <img decoding=\"async\" src=\"https:\/\/ibexaviation.com\/page-show\/radio-navigation\/r9-microwave-landing-system-6.jpg\" alt=\"\" loading=\"lazy\"\/><\/p>\n<ul>\n<li>MLS provides precise aircraft position relative to the selected approach path.<\/li>\n<li>Displayed information includes course, height, and distance.<\/li>\n<li>The MLS approach reference datum is located <strong>50 ft above the runway threshold<\/strong>.<\/li>\n<li>ICAO recommends an accuracy of approximately <strong>13.5 ft<\/strong> at the reference datum.<\/li>\n<li>The maximum permissible error at the maximum range of <strong>20 NM<\/strong> is approximately <strong>27 ft<\/strong>.<\/li>\n<li>Horizontal position error normally does not exceed <strong>20 ft<\/strong>.<\/li>\n<li>Vertical position error is limited to approximately <strong>2 ft<\/strong> at the Aerodrome Reference Datum.<\/li>\n<li>The maximum glide path error is approximately <strong>0.2\u00b0<\/strong> on a standard <strong>3\u00b0<\/strong> glide path.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Microwave Landing System (MLS) ILS (Instrument Landing System) uses radio beams to provide fixed landing guidance, while MLS (Microwave Landing System) uses microwave signals for more flexible guidance. ILS has limited approach paths, whereas MLS supports wider approach angles and curved approaches. MLS offers greater accuracy and is less affected by terrain and signal interference than ILS. Introduction to MLS The Microwave Landing System (MLS) consists of five integrated subsystems. Azimuth Guidance \u2013 Located beyond the stop end of the runway to provide lateral guidance. Elevation Guidance \u2013 Located on&hellip;<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"disable_featured_image":false,"footnotes":""},"categories":[326],"tags":[],"class_list":["post-14526","post","type-post","status-publish","format-standard","hentry","category-cpl-atpl-radio-navigation"],"_links":{"self":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts\/14526","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/comments?post=14526"}],"version-history":[{"count":2,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts\/14526\/revisions"}],"predecessor-version":[{"id":16603,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/posts\/14526\/revisions\/16603"}],"wp:attachment":[{"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/media?parent=14526"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/categories?post=14526"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ibexaviation.com\/pilot-training\/wp-json\/wp\/v2\/tags?post=14526"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}