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Azimuth to TACAN to ZOC

I used to tell my kids that when they were thinking about what they wanted to be in life, their trajectory was much more important than their azimuth. That led to an interesting discussion not only about mathematics but also about the idea of aiming high, regardless of what interests they decided to follow.

In looking into aviation words this month, I stumbled upon ZOC – the zone of confusion around a TACAN (tactical air navigation) beacon. A TACAN beacon is a UHF beacon, similar to a VOR, providing azimuth and range on two separate meters.

It was new to me, but many of you may be familiar with the definition of the same concept with a VOR. The zone of confusion is an area above a VOR where there is an inadequate signal quality for accurately assessing your location. It is also described more basically as an area where signal noise in general provides an unwelcome ZOC. If you’ve ever “lost” a VOR, as I did on my first solo cross-country, you’ll accept the term for what it is – confusing – and sometimes just flying higher or back and forth will resolve that confusion. Modern GPS does not have this issue unless you have a significant antenna problem.

So that’s it: azimuth – your heading in the horizontal plane; TACAN a UHF tactical air navigation beacon; and ZOC – a zone of confusion. Question: Are TACANs only used by the military, or do other pilots also use them?

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