IFR approaches

alphaone

Well-Known Member
On any approach, if the approach title is "ILS-DME" and my aircraft doesn't have DME, I cannot do the approach correct? I ask because I know on some approaches it actually says 'DME required' on the plate. I could do the approach however if I had radar....Correct?
 
If it says "DME or radar required" on the plate, otherwise you'd need DME...

But everything else you said was right.
 
:yeahthat: If it says ILS-DME it just means that you have and added bonus of DME available. But in the notes if it says DME or RADAR required then you need either or both whichever it says.
 
You could shoot the ILS without RADAR or DME by proceding from the IAF at the DuPage VOR. If you wanted to shoot the LOC/DME as a non-precision approach, you would need to use DME to identify the FAF at HITOB and begin your descent to MDA.

If RADAR or DME was required for the ILS and the LOC, it would be listed as a note on the approach plate.
 
The ILS can be shot without DME or RADAR. The LOC needs DME to ID the FAF. The missed for the LOC is at 0.1 DME and no time is listed for the missed because without DME you wouldn't know where to start the timer.

It's an ILS or (LOC/DME). Otherwise it would say ILS or LOC with a note that DME was required for both.
 
Just use your Garmin 430 as your DME!
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Chris_Ford said:
Wait, is that ILS or (Loc/DME) or (ILS or Loc) / DME?

anyone?
That's a great question.

Based on my reading, my impression is that Photopilot is absolutely right. It's ILS or (LOC/DME). If DME was also required for the ILS, the title of the approach would be ILS/DME or LOC/DME or, as Photopilot suggests, that there would be a note requiring DME for everything.

I still have a nagging "but..." left over. The problem is that, without DME you cannot confirm your glideslope intercept altitude. I don't know whether or not that's permitted. Is the fact that your glideslope needle centers at 2000' enough? If so, why do all (most?) ILS approaches have a verification method.

Any TERPS gurus to shed some light?
 
From the horses mouth:

United States Standards for Terminal Instrument Procedures states that, "...shall be identified by a prefix describing the navigational system providing the final approach guidance and the runway to which the final approach guidance is aligned:

a. Non-RNAV...."

"... A slash (/) indicates more than one type of equipment is required to execute the final approach; e.g., VOR/DME, etc. ILS procedures do not require DME to fly the final approach, even if a DME fix has been substituted for one of the marker beacons, hence ILS procedures will not be named ILS/DME. When a LOC procedure requires DME or RADAR to fly the final approach, and is charted on an ILS approach, the procedure name will be ILS. The chart will be noted to indicate DME or RADAR is required for localizer minima, as appropriate. When procedures are combined, the word "or" shall indicate either type of equipment may be used to execute the final approach; e.g., ILS OR TACAN, ...."

So after all of that typing here is the take-away. The title of the approach tells you what navaids you need to fly the FINAL APPROACH SEGMENT. So a VOR means that you need a VOR to fly the FINAL APPROACH segment, but VOR/DME means you need VOR AND DME to fly the final approach segment. "DME Required", "RADAR Required" or "DME or RADAR required" are published on the plate when you need them for some reason other than they are necessary to fly the final approach segment, like you are flying the localizer versus the ILS. As for whether you can fly the approach WITHOUT a DME if it says DME required, my vote is "No" but I couldn't find the regulatory guidance that specifically says so. I think this means that if the title says VOR/DME or if "DME required" appears on the plate, you need the DME to legally fly the approach.
 
The TERPS question I had was whether you are allowed to have an ILS approach without a way of independently verifying the GSI crossing altitude.
 
Sorry, I was answering the original question of the post, i.e., whether you are required to have a DME if the title of the procedure includes DME, or whether you need a DME ONLY if the phrase "DME required" appears on the plate. I'll clarify the answer to that question in this post and then take a stab at YOUR question at the bottom.

I think, based on the above post, that DME is required in both cases, but NOT required if the title says, OR /DME..

In other words, I think that all of the below require DME:
VOR/DME 21
VOR 21 with the words "DME required" printed on the plate.
VOR 21 with the words "DME or RADAR required" and the RADAR doesn't work. (Maybe the field is listed non-Radar on a NOTAM or something).
VOR 21 or NDB/DME 21 (and you have an NDB and a DME, but not a VOR)
VOR/DME or TACAN 21 (since TACAN includes DME)

However, IMHO the following don't require DME:
VOR 21 (DME not mentioned anywhere)
VOR 21 with "DME or RADAR required" and the RADAR works
VOR 21 or NDB/DME 21 (and you have a VOR)

On to the second question...Must there be a way to independently identify the glideslope intercept altitude. I don't think so, but I'm not sure. Here's why I think the answer is "no":

Again from the United States Standards for Terminal Instrument Procedures, the ILS has 3 components, the localizer, the glideslope, and the outer marker. The outer marker may be replaced by an outer compass locator (LOM) or by DME. Paragraph 913 states that when the LOC is out of service you can't fly the approach. When the G/S is out, you can fly the approach as a non-precision (a LOC), and "...When other components become inoperative, the ILS may continue in use with the landing minimums as prescribed in paragraph 350" Paragraph 350 talks about standard minimums for precision and non-precision approaches and makes no mention of there being no way to identify a FAF on a precision. From that I infer that you are not required to be able to independently identify the correct glideslope intercept point to fly the approach, or the paragraph above would be written differently. As for me, I would probably not fly that one in real weather if I had a choice, but I think it would still be legal. Unfortunately, I couldn't find a reference that directly and specifically refers to this question, so I'm kind of reading between the lines here, and giving my interpretation, not FAA guidance. Hopefully, there is someone out there who knows a better reference?
 
fish314 said:
On to the second question...Must there be a way to independently identify the glideslope intercept altitude. I don't think so, but I'm not sure. Here's why I think the answer is "no":

Again from the United States Standards for Terminal Instrument Procedures, the ILS has 3 components, the localizer, the glideslope, and the outer marker. The outer marker may be replaced by an outer compass locator (LOM) or by DME. *** "...When other components become inoperative, the ILS may continue in use with the landing minimums as prescribed in paragraph 350" Paragraph 350 talks about standard minimums for precision and non-precision approaches and makes no mention of there being no way to identify a FAF on a precision. From that I infer that you are not required to be able to independently identify the correct glideslope intercept point to fly the approach, or the paragraph above would be written differently.
That was an excellent analysis. Sounds right.
 
I'll throw my .02 in on this, not that it matters. I think you have to have DME. Section 5-4-5 paragraph 3 of the AIM spells it out (as posted above). There is a naming standard change for approaches going on now (specifically ILS and LOC approaches on the same plate). I read it as, if DME is in the title of the approach you must have DME to fly the approach (speaking to ILS and LOC approaches). So ILS or LOC/DME 17R, I read as ILS/DME or LOC/DME 17R. I very well could be wrong though. I've looked and looked and can not find an example of a ILS or LOC/DME approach plate that has a note requiring DME for the ILS.

"I take it back" http://www.naco.faa.gov/d-tpp/0603/00226ILD17R.PDF

DME required but still named ILS or LOC/DME 17R
 
Wouldn't it be correct to say that if the approach was labeled ILS/DME then DME would be required. However if it said ILS or LOC/DME, DME would only be required for the loc (unless speciffically stated in the notes)?
 
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