What is the correct terminology for the name of the aircraft instrument that looks like this?



2 Answers 2


That image is a basic representation of a course deviation indicator, as mentioned by Steve H. An actual gauge would look like this:

enter image description here
Image Source

In your image, it shows that the aircraft needs to correct to the left and a little upwards, so that it will be on the glideslope as shown here.

ILS Landing

  • $\begingroup$ Am I misreading it? It seems to indicate a little right and high, so correction is left and down? Mind you, I don't have an IR :) $\endgroup$
    – Simon
    Commented Apr 1, 2015 at 14:19
  • $\begingroup$ The crosshair is the location you want to be in; the circle in the centre is the aircraft. So, in the image in the question, the aircraft needs to move up and left to be on the crosshair. $\endgroup$ Commented Apr 1, 2015 at 14:56
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    $\begingroup$ @Simon I'm not instrument rated either. According to my understanding, the circle is the aircraft, horizontal line is the glideslope (see the 2nd image in my answer), vertical line is localizer. You need to be left and up. $\endgroup$
    – Farhan
    Commented Apr 1, 2015 at 14:57
  • $\begingroup$ @Farhan that's correct assuming you're not flying the localizer back-course in which case it would be reverse sensing. You wouldn't generally be using the glide slope in that case though. There have been incidents attributed to unfamiliarity with instruments such as the artificial horizon, iirc russian aircraft traditionally showed the aircraft attitude rather than the position of the horizon (i.e. the exact opposite) and there might well be some old CDIs around showing the opposite of what you would expect as well. $\endgroup$
    – falstro
    Commented Apr 1, 2015 at 15:36
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    $\begingroup$ I think part of the problem here is that there are two CDIs above. The top one shows the plane low and right, the second low and left.. although the second one is nearly centered. $\endgroup$ Commented Apr 1, 2015 at 22:28

That is the course deviation indicator, or CDI.

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    $\begingroup$ Smashing, a quick Google and all the information on it I could ever want! $\endgroup$
    – GPPK
    Commented Apr 1, 2015 at 10:22

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