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As I was looking at the approach charts for KCXY while answering this question, I realized that the GPS "overlay-style" approach to RW8 also requires RADAR.

Since the HAR VOR isn't even shown on this Approach, and it has an IF, why should RADAR be required?

Note that the RNAV (GPS) RWY 26 approach to this airport does not require radar.

enter image description here

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  • $\begingroup$ Possible duplicate of Why is radar required on some FAA instrument approaches? $\endgroup$ – abelenky Jan 13 '16 at 14:59
  • $\begingroup$ I'm going to hazard a guess that it has to do with the close proximity of Harrisburg MDT. In a non-radar environment, an aircraft flying this approach would surely limit traffic being allowed to approach or depart MDT. Perhaps the RADAR requirement is to limit this approach to use when it would have a minimal impact on MDT traffic. $\endgroup$ – J Walters Jan 13 '16 at 15:00
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    $\begingroup$ @abelenky its not a duplicate of that answer, and in fact, I reference that answer. $\endgroup$ – rbp Jan 13 '16 at 15:01
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    $\begingroup$ @JonathanWalters by that logic, every approach inside busy airspace would say "RADAR REQUIRED", which we know is not true. $\endgroup$ – rbp Jan 13 '16 at 15:09
  • $\begingroup$ No, that logic leads to exactly the sort of answer you give for your CAT II / III requirements below. Close proximity creating an impact on traffic for some reason. $\endgroup$ – J Walters Jan 13 '16 at 15:21
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The immediate reason seems to be that for RNAV approaches that start at an IF (Intermediate Fix) - not an IAF (Initial Approach Fix) - radar is required per the ATC orders (4-8-1h):

issue approach clearance [...] only after the aircraft is:

  1. Established on a heading or course direct to the IF at an angle not greater than 90 degrees, provided the following conditions are met:

[...]

(b) Radar monitoring is provided to the IF.
(c) The SIAP must identify the intermediate fix with the letters “IF.”

The RNAV 26 approach that you mentioned does have an IAF, so according to the same rules radar isn't always required for it.

You might now ask, why is radar required for RNAV approaches that start at an IF? Because, it doesn't have an IAF.

The next question is why doesn't it have an IAF? Probably because of higher terrain north of the approach corridor? Or maybe (as per @Jonathan Walter's answer) there is sufficient Radar coverage to vector to the IF, so it doesn't need an IAF.

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