At the top of this approach chart for KDNN in the briefing section, it is stated that "Simultaneous operation of I-DNN and GQO DME required."

If my aircraft is not RNAV/GPS or DME equipped can I fly the full ILS approach and rely on "Radar" to identify ROLTE INT (IF)?

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  • $\begingroup$ Are you talking about having ATC tell you when you are at ROLTE? If you don’t have any method of determining your distance to the runway what would you use for vertical guidance? $\endgroup$ – TomMcW Mar 25 '18 at 1:17
  • $\begingroup$ @TomMcW - yes, ATC telling me I'm at ROLTE. Then I descend from 2900 down to 2600 until intercepting the GS. If I fly down the GS to DA, why do I need DME? Question is, does the comment about simultaneous I-DNN and GQO DME in the briefing section mean I can't fly the ILS (using radar for ROLTE) if I don't have DME capability? (e.g., why do I need DME if I can use ATC? ) $\endgroup$ – 757toga Mar 25 '18 at 3:27
  • $\begingroup$ Oh sorry. For some reason I was thinking it was LOC only. So after the turn at ROLTE you’re set up for full ILS, so no need for DME. I’m on the same page now. Would you not be able to capture the LOC at ROLTE anyway? $\endgroup$ – TomMcW Mar 25 '18 at 3:36
  • $\begingroup$ Why do you need a charted approach at all if you can use ATC? AFAIK the whole point of a charted approach is to make it hands-off for ATC. If you lose coms you wouldn’t be able to follow the approach without DME or GPS - unless you just count on flying the 132° radial until you capture the LOC, which seems entirely reasonable at 6.2 nmi. But the plate says otherwise, so not sure where that leaves it legal-wise. $\endgroup$ – TomMcW Mar 25 '18 at 3:50
  • $\begingroup$ @TomMcW - You need to know you are at ROLTE so you can begin your descent if you're flying the LOC only. If you don't have DME, you could use the GQO R-132 intersection with the LOC, or radar to id ROLTE, but without DME (unless using radar), you could not id EWADA. My question just revolves around the verbiage in the briefing section of the plate that suggests that DME is an irreplaceable requirement. (even though you can use radar instead of DME) [remember, scenario is no GPS or DME equipment.] $\endgroup$ – 757toga Mar 25 '18 at 3:59

Tl;dr: This is really an edge case and I can’t come up with any specific wording that says “yes” or “no”. But from the following info I’d say you cannot unless ATC authorizes it.

Since the chart specifically indicates it as required it would be illegal to use the approach. Paragraph 5-5-4 a 2 of the AIM lists under pilot responsibilities:

  1. Follows the procedure as shown on the IAP, including all restrictive notations

But according to this answer ATC can approve an approach even when some equipment is inop. The answer seems to be concerning inop. NAVAID equip, rather than inop. equipment on the aircraft. Also, the section of the AIM he refers to (5-4-7d) does not include what he says. Paragraph 5-4-6d states:

The name of an instrument approach, as published, is used to identify the approach, even though a component of the approach aid, such as the glideslope on an Instrument Landing System, is inoperative or unreliable. The controller will use the name of the approach as published, but must advise the aircraft at the time an approach clearance is issued that the inoperative or unreliable approach aid component is unusable.

This would suggest that ATC can approve an approach with inop. equipment.

If you consider telling you when you arrive at ROLTE to be “vectoring” then ATC can give you vectors as far as the FAF. FAA order JO 7110.65W, which gives instructions for ATC indicates in paragraph 5-9-1 a 2.

  1. If specifically requested by the pilot, aircraft may be vectored to intercept the final approach course inside the approach gate but no closer than the final approach fix.

Note that where you have highlighted “RNAV 1-GPS or RADAR or DME REQUIRED” is on the IAF at GQO, but not on ROLTE. This would indicate to me that you can count on any of those to get you to the IAF, but not beyond it. The word RADAR on the chart at ROLTE and EWADA indicate that those fixes are depicted on the ATC radar screen. This would certainly make it possible for them to tell you when you’ve reached the fix, but I don’t know if you can count on them to do it. And without that or DME you would have no accurate way of identifying the FAF. They may not have time to monitor you after you’ve reached the IAF, so that’s why I say it would require ATC approval.

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    $\begingroup$ Good comments. As nav systems become more advanced and new methods of flying iaps are developed chart complexity has increased. Readability of charts is under continuous review and discussion. Regarding the term "radar" underlined in red on the plate, these are "radar fixes" and are in fact a legit form of fix id. (Just ask ATC to tell you when you are over ROLTE for example). Take a look at this AOPA ref. for discussion on this issue: aopa.org/advocacy/airports-and-airspace/navigation-and-charting/… $\endgroup$ – 757toga Mar 25 '18 at 23:44
  • $\begingroup$ @757toga Thanks for that link. It appears this plate has not been updated to the new format, but my guess is that when it does it will say “DME required to define EWADA.” That, I think would clarify that you can’t use it without DME. What’s truly confusing on this chart is that box under the GQO VOR that says “RNAV1-GPS or RADAR or DME REQUIRED.” That seems to contradict what’s in the briefing strip. I’m thinking that’s what’s required for ENTRY into the procedure, but DME is required to define the IF and FAF. But I could be wrong $\endgroup$ – TomMcW Mar 26 '18 at 0:20
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    $\begingroup$ you need EWADA if you are flying the LOC approach (without the GS). You can, without DME when EWADA is identified by radar, start your timing to the MAP. However, if you are flying the full ILS (with GS) your MAP is the DA (point you reach the altitude of 959 ft. msl on the GS) $\endgroup$ – 757toga Mar 26 '18 at 0:36
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    $\begingroup$ @757toga They definitely need to update this plate. DME should only be required for LOC only. $\endgroup$ – TomMcW Mar 26 '18 at 0:42
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    $\begingroup$ What @TomMcW said. As written, it is needed for both because of the note, however there is no good reason to require DME when flying the entire ILS procedure (unless maybe they want it just in case the glideslope fails so that you can always identify the MAP, but I don't ever remember seeing anything like this mentioned in procedure design documents). $\endgroup$ – Lnafziger Mar 26 '18 at 3:34

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