MLS

Introduction The MLS is a system of precission approach for landing by instruments and constitutes a kind of an alternative to the ILS system. It provides information about the azimuth, optimal angle of descent and the distance, as well as data about the reverse course in case of an unsuccessful approach. It has several advantages compared to the ILS, for example a greater number of possible executed approaches, a more compact ground equipment,...

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ELTs

Emergency Beacons There are three types of beacons used to transmit distress signals, EPIRBs (for maritime use), ELTs (for aviation use), and PLBs (used for land-based applications).   Emergency Locator Transmitters (ELTs) ELTs were the first emergency beacons developed and most U.S. civil aircraft are required to carry them. ELTs were intended for use on the 121.5 MHz frequency...

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frequency band table

Frequency or frequency bandSubpartClass of stationRemarks 108.000 MHzQRadionavigation land test 108.000-108.050 MHzQVHF omni-rangeVHF omni-range (VOR) [87.475(b)(5)] 108.050 MHzQRadionavigation land test 108.050-108.100 MHzQVHF omni-rangeVHF omni-range (VOR) [87.475(b)(5)] 108.100 MHzQRadionavigation land test 108.100-108.150 MHzQLocalizerILS localizer [87.475(b)(4)] 108.150 MHzQRadionavigation land test 108.150-111.950 MHzQLocalizerILS localizer [87.475(b)(4)] 111.950-117.950 MHzQVHF omni-rangeVHF omni-range (VOR) [87.475(b)(5)] 118.000-121.400...

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Airband

his article is about the radio spectrum used in aviation. For bands named Air, see Air  A typical aircraft VHF radio. The display shows an active frequency of 123.5MHz and a standby frequency of121.5 MHz. The two are exchanged using the button marked with a double-headed arrow. The tuning control on the right only affects the standby frequency. Airband or Aircraft band is the name for a group...

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Airport Runway Numbering

When you leave the comforts of home and familiar streets and roadways and enter your favorite airport, you’re likely to encounter strange words, devices, and methods of doing things – at least they may seem strange to the uninitiated. Once you learn the reasons for the way airports operate, build, and function, these once strange concepts begin to make perfect sense. The airport runway numbering system is one of those things. Jets in our hangars...

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VASI and PAPI

A PAPI and a VASI are very similar in the the information they provide. The only functional differences between the VASI and PAPI is that the VASI has the red over the white, the PAPI the white actually goes to the right of the red, and the PAPI offers higher precision (or more glideslopes depending how you look at it a larger airliner with a high cockpit may elect to fly a slightly higher glidepath). The concept is the same though. A VASI looks...

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