Locator outer markerとは 意味・読み方・使い方

A locator outer marker, or LOM, is a navigation aid used as part of an instrument landing system (ILS) instrument approach for aircraft in the United States and other countries. An LOM is an non-directional beacon (NDB) colocated with the outer marker beacon in the ILS approach, so that aircraft can navigate directly to the location using the NDB as well as be alerted when they fly over it by the beacon. The LOM is becoming less important now that GPS navigation is well established in the aviation community. Canada has taken the process further and abandoned marker beacons altogether, replacing the outer marker in ILS approaches entirely with the NDB.