Visual approach slope indicator: Difference between revisions

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Revision as of 00:48, 24 November 2018

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Basic visual approach slope indicators consist of one set of lights set up some {{convert|7|m|ft}} from the start of the runway. Each light is designed so that it appears as either white or red, depending on the angle at which it is viewed. When the pilot is approaching the lights at the proper angle, meaning the pilot is on the [[glide slope]], the first set of lights appears white and the second set appears red. When both sets appear white, the aircraft is too high, and when both appear red it is too low. This used to be the most common type of visual approach slope indicator system; however, it is being phased out and replaced by [[Precision approach path indicator]]s (PAPIs), which are closer together and therefore more efficient to site and maintain.

A mnemonic to remember the colors and their meaning is :<br>

''White over White, you're high as a kite'' / ''you'll fly all night'' / ''check your height''<br>

''Red: White over White, you're alright.high as a kite / you''<br>ll fly all night / check your height

: Red over White, you're alright.

'': Red over Red, you're dead.''<ref>[http://www.freefalcondoc.com/index.php?title=Visual_Approach_Slope_Indicator Free Falcon wiki]{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><br>

''White over Red, unsaid'' / ''you're under head. ("White over red" isn't actually possible unless the VASI installation is badly off, or else if you're upside down on final.)''<ref>{{Cite web|url=http://aviation.stackexchange.com/questions/33151/what-does-a-white-over-red-vasi-indicate|title=What does a white over red VASI indicate?|website=aviation.stackexchange.com|access-date=2016-11-14}}</ref>

: White over Red, unsaid / you're under head.

''White over Red, unsaid'' / ''you're under head. ("White over red" isn't actually possible unless the VASI installation is badly off, or else if you're upside down on final.)''<ref>{{Cite web |url=http://aviation.stackexchange.com/questions/33151/what-does-a-white-over-red-vasi-indicate |title=What does a white over red VASI indicate? |website=aviation.stackexchange.comAviation StackExchange |access-date=2016-11-14}}</ref>

==See also==