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I was looking at the ILS or LOC RWY 9 at KJZI today and I noticed that it had lower minima for when you can identify an intermediate fix (YOCUB). That made sense, but the entire approach requires DME. So, if that's the case, why even bother having non-DME minima?

Both of the missed approaches require DME. Under what circumstance could you shoot this approach but your MDA would be 520?

Here's the current plate: http://155.178.201.160/d-tpp/1609/05354IL9.PDF

ILS or LOC RWY 9

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2 Answers 2

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Conceivably the I-ETI DME transponder could be out of service, preventing you from identifying YOCUB (unless you have a second VOR or GPS), but you could still identify BASSO on the CHS DME for the missed.

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    $\begingroup$ That makes good sense. And with a single VOR receiver, you could switch back and forth to identify your IAF and JEBOP but by the time you get to 520 feet, they don't want you fiddling with your nav/com while you descend another 140 feet. I buy that. I'm gonna accept this answer. I think I have a connection to someone who used to design TERPS and I'll verify that this is correct (however, I presume it is). $\endgroup$
    – D. Patrick
    Sep 9, 2016 at 18:32
  • $\begingroup$ @ymb1, that's what I mean. You can identify your IAF with a single VOR but once you start the approach, they want you to use the time table and descend to the higher MDA rather than switching back and forth between the localizer and the VOR. If you have dual VOR receivers, you can identify the intermediate fixes and can descend to the lower MDA instead. $\endgroup$
    – D. Patrick
    Sep 11, 2016 at 12:27
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    $\begingroup$ OK, I think that you can't fly a DME REQUIRED approach if your DME is out, but I can't find a regulation to reference. This approach, as it turns out, is mislabeled and on Monday they're going to work on issuing an FDC NOTAM to correct it. I did find a reference in the AIM that said that the DME REQUIRED in the pictograph only covered IAF through FAF, not the missed approach and that it was up to the pilot to determine if the aircraft is appropriately equipped to fly the missed. $\endgroup$
    – D. Patrick
    Sep 11, 2016 at 12:34
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The minima are not necessarily DME related; however you can identify the YOCUB fix using a DME. All fixes in the approach can be identified using the localizer and the Charleston Vortac, save the BASSO hold fix, which would require a DME. An alternate method is to use an IFR approved GPS as a 'cheater DME' (my personal term; don't try to look it up) to fly the approach if your aircraft has equipment type G and no second nav radio.

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    $\begingroup$ This still doesn't seem to answer the question. It specifies DME or dual VOR to use the YOCUB minima, but the whole approach is labeled DME required. If you don't have DME you can't use this approach at all, can you? $\endgroup$
    – TomMcW
    Sep 9, 2016 at 18:31

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