Radar Required

[ScottM]

http://flightaware.com/resources/airport/DKB/IAP/ILS+OR+LOC+RWY+02/pdf is the ILS02 at KDKB. I flew this approach this past weekend and had radar services. With the big bold letters 'RADAR REQUIRED' I would not even question having it. But then I saw in the approach description the words 'DME or RADAR Required'. So which is it? RADAR Required or may DME also be used in lieu of radar?

 

[flyersfan31]

http://flightaware.com/resources/airport/DKB/IAP/ILS+OR+LOC+RWY+02/pdf is the ILS02 at KDKB. I flew this approach this past weekend and had radar services. With the big bold letters 'RADAR REQUIRED' I would not even question having it. But then I saw in the approach description the words 'DME or RADAR Required'. So which is it? RADER Required or may DME also be used in lieu of radar?

I'm not familiar with RADER. I think if they asked for it, it must be very specialized equipment.

 

[Ghery]

I'd have to say DME or Radar. Note that the fixes on the approach course are all labeled with DME fixes, so why couldn't you use it? However, it does look like a conflict between the description and the big print in the plan view. Contact NACO and see about getting it fixed?

 

[roncachamp]

http://flightaware.com/resources/airport/DKB/IAP/ILS+OR+LOC+RWY+02/pdf is the ILS02 at KDKB. I flew this approach this past weekend and had radar services. With the big bold letters 'RADAR REQUIRED' I would not even question having it. But then I saw in the approach description the words 'DME or RADAR Required'. So which is it? RADAR Required or may DME also be used in lieu of radar?

Radar is required. DME can be used to determine the various fixes but not to position the aircraft on the localizer.

 

[BillTIZ]

Radar is required. DME can be used to determine the various fixes but not to position the aircraft on the localizer.

Agreed.. there are no "Feeder" or "transition routes" to get to the localizer.. you need Radar to get established.. then you can use DME for the step down fixes.

 

[jesse]

There is no initial approach fix which will make it pretty hard to do the approach without radar. If you were RNAV equipped they could clear you to the intermediate fix but radar monitoring is required for them to do that.

I don't see any good way to start the approach without radar which is why it is RADAR REQUIRED. The other part sounds like a typo.

 

[jesse]

This got me thinking. Is it possible to have an approach without an IAF where radar isn't required?

 

[poadeleted20]

There are two different notations dealing with two different issues. Any time you need ATC radar to enter the approach, they put the big RADAR REQUIRED in the planform view. If you need something other than the systems listed in the title in order to fly the approach, they list that system as "required" in the notes system.

In this case, clearly, you cannot enter the approach without ATC radar (no feeder or transition route from an airway fix and it doesn't start at a navaid), so they put the big RADAR REQUIRED on the planform view.

However, the "DME or Radar required" in the notes is a little more complicated. While it is true that once you get onto the approach, you can fly the full ILS all the way to either the primary or alternate missed approach holds with neither ATC radar nor DME, you must have either DME or Radar to fly the LOC-only version in order to identify the FAF and stepdown fixes. Obviously, they can't make this an "ILS or LOC/DME" approach, since you can use an ATC radar fix instead of DME on the LOC portion, and if they put the "/DME" in the title, you wouldn't be allowed to fly the LOC approach without DME.

Put it all together, and I think what happened is they put in the "DME or Radar required" note even though DME is not required for any version of the ILS because you must have one or the other for the LOC approach, and you always have to have Radar for even the ILS. OTOH, for the LOC, if you don't have DME, ATC must call the FAF and stepdown fixes to you. As a result, the "DME or Radar required" does not add any requirement to the ILS which isn't there already (if radar is required for everyone, you've got that already), but it does remind the LOC flyers of the need for either DME or to get ATC to call the fixes.

 

[poadeleted20]

This got me thinking. Is it possible to have an approach without an IAF where radar isn't required?

I don't believe so, but I'm not sure. In theory, one could have an Advanced RNAV approach (GPS, RNAV(GPS), etc) which started at an IF without radar being required by TERPS (since, within certain limits, an Advanced RNAV aircraft can enter an approach at the IF with neither a course reversal nor radar vectors), but operationally, all RNAV-direct clearance require the aircraft to be radar monitored.

 

[ScottM]

There are two different notations dealing with two different issues. Any time you need ATC radar to enter the approach, they put the big RADAR REQUIRED in the planform view. If you need something other than the systems listed in the title in order to fly the approach, they list that system as "required" in the notes system.

In this case, clearly, you cannot enter the approach without ATC radar (no feeder or transition route from an airway fix and it doesn't start at a navaid), so they put the big RADAR REQUIRED on the planform view.

However, the "DME or Radar required" in the notes is a little more complicated. While it is true that once you get onto the approach, you can fly the full ILS all the way to either the primary or alternate missed approach holds with neither ATC radar nor DME, you must have either DME or Radar to fly the LOC-only version in order to identify the FAF and stepdown fixes. Obviously, they can't make this an "ILS or LOC/DME" approach, since you can use an ATC radar fix instead of DME on the LOC portion, and if they put the "/DME" in the title, you wouldn't be allowed to fly the LOC approach without DME.

Put it all together, and I think what happened is they put in the "DME or Radar required" note even though DME is not required for any version of the ILS because you must have one or the other for the LOC approach, and you always have to have Radar for even the ILS. OTOH, for the LOC, if you don't have DME, ATC must call the FAF and stepdown fixes to you. As a result, the "DME or Radar required" does not add any requirement to the ILS which isn't there already (if radar is required for everyone, you've got that already), but it does remind the LOC flyers of the need for either DME or to get ATC to call the fixes.

Thanks Ron that makes the most sense.

 

[Ghery]

Thanks Ron that makes the most sense.

Always learning here. Thanks.

 

[jesse]

I don't believe so, but I'm not sure. In theory, one could have an Advanced RNAV approach (GPS, RNAV(GPS), etc) which started at an IF without radar being required by TERPS (since, within certain limits, an Advanced RNAV aircraft can enter an approach at the IF with neither a course reversal nor radar vectors), but operationally, all RNAV-direct clearance require the aircraft to be radar monitored.

The following is in the AIM:

ATC may clear aircraft that have filed an Advanced RNAV equipment suffix to the intermediate fix when clearing aircraft for an instrument approach procedure. ATC will take the following actions when clearing Advanced RNAV aircraft to the intermediate fix:
1.)Provide radar monitoring to the intermediate fix.
2.) Advise the pilot to expect clearance to the intermediate fix at least 5 miles from the fix.
3.) Assign an altitude to maintain until the fix.
4.) Insure the aircraft is on a course that will intercept the intermediate segment at an angle not greater than 90 degrees and is at an altitude that will permit normal descent from the intermediate fix to the final approach fix.

It certainly sounds like an approach without an IAF must be radar required.

I honestly never realized before that it was possible to have an approach without an IAF.

 

[poadeleted20]

The following is in the AIM:
It certainly sounds like an approach without an IAF must be radar required.

That's a 7110.65/AIM procedural issue, not (to my knowledge) a TERPS requirement. Yes, that effectively makes ATC radar a requirement, but it doesn't mean the chart will be stamped "RADAR REQUIRED." We'll need someone more expert on TERPS to verify that part.

 

[gismo]

Put it all together, and I think what happened is they put in the "DME or Radar required" note even though DME is not required for any version of the ILS because you must have one or the other for the LOC approach, and you always have to have Radar for even the ILS. OTOH, for the LOC, if you don't have DME, ATC must call the FAF and stepdown fixes to you. As a result, the "DME or Radar required" does not add any requirement to the ILS which isn't there already (if radar is required for everyone, you've got that already), but it does remind the LOC flyers of the need for either DME or to get ATC to call the fixes.

I think your analysis is likely correct but I'm having a little trouble with the "DME or RADAR required" note. Seems to me that the lack of any navaids at the stepdown fixes or ID radials from some nearby VOR would covey the need for radar ID of said fixes quite well making the note kinda redundant given the need for RADAR to get on the approach in the first place.

This also brings up another point of confusion for me as I now am wondering if a "DME required" never applies to an ILS approach and only to the associated LOC approach.

 

[ghogue]

This also brings up another point of confusion for me as I now am wondering if a "DME required" never applies to an ILS approach and only to the associated LOC approach.

As far as I can tell, does not apply to ILS.
See this from TERPs.

 

[poadeleted20]

I think your analysis is likely correct but I'm having a little trouble with the "DME or RADAR required" note. Seems to me that the lack of any navaids at the stepdown fixes or ID radials from some nearby VOR would covey the need for radar ID of said fixes quite well making the note kinda redundant given the need for RADAR to get on the approach in the first place.

The FAA feels it is necessary to add the note any time you need something other than the items in the chart title.

This also brings up another point of confusion for me as I now am wondering if a "DME required" never applies to an ILS approach and only to the associated LOC approach.

Take a look at the ILS 4 to Easton MD (KESN) -- big "DME REQUIRED" in the planform view which applies to the ILS (the LOC version already being "LOC/DME") due to the inability to ID RIKME any other way.

 

[gismo]

The FAA feels it is necessary to add the note any time you need something other than the items in the chart title.

Take a look at the ILS 4 to Easton MD (KESN) -- big "DME REQUIRED" in the planform view which applies to the ILS (the LOC version already being "LOC/DME") due to the inability to ID RIKME any other way.

That opinion seems to be in direct conflict with the Terps excerpt that ghouge provided:

"ILS procedures do not require DME to fly the final approach, even if a DME fix has been substituted for one fo 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 appraoch, the procedure name will be ILS. The chart will be noted to indicate DME or RADAR is required for localizer minima, as appropriate."

I suppose that technically the DME isn't required for the final segment, only for the IF and associated HILPT and I see your point, the HILPT is needed (both due to the lack of a "NoPT" on the feeder from PXT and the need to lose 2500 feet in the PT) and like you I see no other way to identify RIKME except DME. Seems like it might be better if the FAA were to make that note read:
"DME required for the ILS approach" since one might otherwise assume DME was only needed for the LOC. Certainly this is at least as ambiguous as the lack of a "RADAR or DME required" on the DLB ILS 02, if not more so.

I guess that this approach at ESN is unusual in two aspects, one as discussed it requires DME and two it falls outside the common idea that "all ILSs are alike, see one and you've seen them all". My take away is that whenever I see a "xxx required" note on the plan view or in the text box I'd better figure out why it's there even if it's an ILS.

 

[poadeleted20]

That opinion seems to be in direct conflict with the Terps excerpt that ghouge provided:

"ILS procedures do not require DME to fly the final approach, even if a DME fix has been substituted for one fo 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 appraoch, the procedure name will be ILS. The chart will be noted to indicate DME or RADAR is required for localizer minima, as appropriate."

No conflict -- different issues. In the ESN case, because RIKME is identifiable only with DME, DME is required to enter the approach, hence the "DME REQUIRED" in the planform view, regardless of the FAF issues. If there were a way to identify RIKME for the HPILPT, IAF, and/or letdown to the GS intercept altitude with just VOR's, then that note would go away, and DME would be required only to fly the LOC approach (to identify WEGRO as the FAF), and the "LOC/DME" in the title would take care of that.

I suppose that technically the DME isn't required for the final segment, only for the IF and associated HILPT and I see your point, the HILPT is needed (both due to the lack of a "NoPT" on the feeder from PXT and the need to lose 2500 feet in the PT) and like you I see no other way to identify RIKME except DME. Seems like it might be better if the FAA were to make that note read:
"DME required for the ILS approach" since one might otherwise assume DME was only needed for the LOC.

One might so assume if one was not properly trained. However, the chart is titled and labeled as required by TERPS.

Certainly this is at least as ambiguous as the lack of a "RADAR or DME required" on the DLB ILS 02, if not more so.

No abiguity whatsoever -- DME is required to fly any version of this approach, and that requirement is clearly stated in big, bold, capital letters.

I guess that this approach at ESN is unusual in two aspects, one as discussed it requires DME and two it falls outside the common idea that "all ILSs are alike, see one and you've seen them all".

One should never assume something like that.

My take away is that whenever I see a "xxx required" note on the plan view or in the text box I'd better figure out why it's there even if it's an ILS.

Well, there's nothing wrong with understanding the "why," but what's most important is seeing and complying with the restriction whether you understand why or not.

 

[ghogue]

That opinion seems to be in direct conflict with the Terps excerpt that ghouge provided:

"ILS procedures do not require DME to fly the final approach, even if a DME fix has been substituted for one fo 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 appraoch, the procedure name will be ILS. The chart will be noted to indicate DME or RADAR is required for localizer minima, as appropriate."

Ron's explanation is correct. In my post above I made the assumption you were referring to "DME" in the title and that's what the excerpt from TERP's was in reference to.

In spite of the fact that TERPs says it isn't allowed, in the past I have seen a few examples of approaches titled ILS/DME. I don't remember which ones they were and after a cursory search, I haven't found any. It's possible it's an error in the title, but I think possibly, it was allowed in the past. Note the "change bar" next to the related text in the TERPs excerpt. This was in Change 19 of the manual. Perhaps they are going back and changing the ones listed as ILS/DME, and that's why I couldn't find any. Not really sure.

edit: Just found an example, KEWR COPTER ILS/DME RWY 22L. Yes, it's a Copter approach, but I doubt the naming convention would be any different.

The more I think about it, I think it (DME) applied to flying the approach as a Localizer, and now that the approaches are being renamed ILS or LOC RWY X, they are applying the DME requirement (in the title) to the LOC and removing it from the ILS portion. Just a supposition on my part.

 

[olasek]

This is an ILS with one of those "Radar or DME."

http://www.airnav.com/depart?http://204.108.4.16/d-tpp/1010/00251ILD14.PDF

 

[Everskyward]

In spite of the fact that TERPs says it isn't allowed, in the past I have seen a few examples of approaches titled ILS/DME. I don't remember which ones they were and after a cursory search, I haven't found any.

Maybe you are thinking of approaches in other countries? Here's one. I think they are pretty common in other countries.

 

[ghogue]

Maybe you are thinking of approaches in other countries? Here's one. I think they are pretty common in other countries.

Actually, no, they were here in the US. I just found two more, one in Burlington, VT (KBTV) ILS/DME RWY33.
Another in Spokane, WA at Felts Field KSFF, ILS/DME RWY21R.
As I mentioned earlier, I think the ones like that have or are being changed to "ILS or LOC/DME RWYXX", but perhaps that's not it.

 

[olasek]

if a "DME required" never applies to an ILS approach and only to the associated LOC approach.

And I have a follow up question...
In case of LOC approach which requires DME distances to indentify intermediate fixes, can I substitute an IFR certified GPS for this DME?. For example a G1000 gives me a distance to runway threshold, can I use it instead of DME distances? For example in this approach to identify the OSSAJ fix?
http://204.108.4.16/d-tpp/1010/00251ILD14.PDF

 

[poadeleted20]

Actually, no, they were here in the US. I just found two more, one in Burlington, VT (KBTV) ILS/DME RWY33.

Wouldn't DME be required even on the ILS in order to step down to the 3700 GS intercept altitude from 4800?

Another in Spokane, WA at Felts Field KSFF, ILS/DME RWY21R.

Again, wouldn't DME be required to leave 6100 down to 4100 for the GS intercept?

In each case, it's different than identifying the FAF by DME as you must in most of those LOC/DME approaches, where GS intercept becomes the FAF for the ILS.

 

[poadeleted20]

In case of LOC approach which requires DME distances to indentify intermediate fixes, can I substitute an IFR certified GPS for this DME?

Absolutely. This is authorized in the AIM, Table 1-1-6. However, you have to be careful if you have one of the older GPS's which doesn't have non-GPS approaches in its database. If the DME is on the LOC rather than a VOR, the LOC location may not be in the database, and you'll have to measure the distance off something else that is.

 

[ghogue]

Wouldn't DME be required even on the ILS in order to step down to the 3700 GS intercept altitude from 4800?

Again, wouldn't DME be required to leave 6100 down to 4100 for the GS intercept?

In each case, it's different than identifying the FAF by DME as you must in most of those LOC/DME approaches, where GS intercept becomes the FAF for the ILS.

I listed these two approaches just to show examples of ILS/DME on the chart title, when the TERPS states it will not be titled that way. I agree DME would be necessary for the stepdown as you mentioned, however DME (or other navaids) listed in the title are supposed to indicate that the component listed is required for the final approach, not a stepdown prior to the FAF.

Just so everybody understands, in no way am I claiming to be an expert in TERPs. Just trying to apply whatever knowledge I have to the topic, and always willing to learn something new.

 

[poadeleted20]

I listed these two approaches just to show examples of ILS/DME on the chart title, when the TERPS states it will not be titled that way. I agree DME would be necessary for the stepdown as you mentioned, however DME (or other navaids) listed in the title are supposed to indicate that the component listed is required for the final approach, not a stepdown prior to the FAF.

I'd like to hear Wally Roberts say that. I guess my thinking is you can't get to the final approach without those stepdowns, and that's why they'd make it ILS/DME. Or it just may be they are old approaches which haven't been updated to the current standard in that regard.

 

[gismo]

I'd like to hear Wally Roberts say that. I guess my thinking is you can't get to the final approach without those stepdowns, and that's why they'd make it ILS/DME. Or it just may be they are old approaches which haven't been updated to the current standard in that regard.

OK, now I'm more confused than ever. I thought that DME was only supposed to be in the title if it was required to fly (rather than get to) the approach beyond the FAF. I would have thought that applied to the vertical as well as horizontal.

Also confusing to me is the ramification of a "DME REQUIRED" on the plan view of an ILS/LOC approach. I thought that this meant DME was needed to reach the FAF and/or identify that fix when flying the LOC but obviously there are approaches where this also applies to the co-charted ILS. How do you tell the difference?

Perhaps you could put together a list or flowchart defining the implications of the various scenarios where DME affects an approach, i.e. in the title vs on the plan view vs in the notes.

On a related note I can't see the reason DME is in the title of the ILS or LOC/DME 18 at KMSN. Each required fix appears to be identified by a crossing radial from the DLL VOR so why is DME needed. Is it the missed approach point and the lack of timing data? Seems like you could easily figure the time from the FAF to the MAP on your own but I vaguely recall that you can't use timing if there's no timing table on the chart.

 

[poadeleted20]

On a related note I can't see the reason DME is in the title of the ILS or LOC/DME 18 at KMSN. Each required fix appears to be identified by a crossing radial from the DLL VOR so why is DME needed. Is it the missed approach point and the lack of timing data? Seems like you could easily figure the time from the FAF to the MAP on your own but I vaguely recall that you can't use timing if there's no timing table on the chart.

Here's the approach about which Lance is speaking:
http://204.108.4.16/d-tpp/1010/00245ILD18.PDF
The reason for the /DME is just as he said -- no timing for the LOC MAP, just DME. And his vague memory is correct -- no timing published, no timing authorized. To find out why timing isn't provided on this particular approach, you'd have to check with the designers/TERPS.

 

[gismo]

Here's the approach about which Lance is speaking:
http://204.108.4.16/d-tpp/1010/00245ILD18.PDF
The reason for the /DME is just as he said -- no timing for the LOC MAP, just DME. And his vague memory is correct -- no timing published, no timing authorized. To find out why timing isn't provided on this particular approach, you'd have to check with the designers/TERPS.

I meant to include a link to the approach, thanks for covering that. A big part of my problem here is that I've been flying with DME since I got my IR about 25 years ago and IFR GPS since that became available and as a result I normally don't have any reason to care if DME is required (and with the GPS even what it's required for is generally just a curiosity issue). But for the occasional trip without such aids (e.g. in someone else's airplane) I'd like to be more aware.

 

[chucky]

Here's one where the note "Radar or DME required" explicitly says for the localizer approach only: PVD ILS-5.

 

[olasek]

If the DME is on the LOC rather than a VOR, the LOC location may not be in the database, and you'll have to measure the distance off something else that is.

Measuring from the runway treshold is OK instead of LOC distances? Because this is what I see given me to say in G1000 - you can see distances to RWY counted down. I know that position of the LOC (that is to say the actual hardware) is a bit displaced (a couple thousand feet?) from the beginning of the runway so there would be some difference.

 

[poadeleted20]

Measuring from the runway threshold is OK instead of LOC distances?

It is, as long as the chart presents the distance of the fix from the runway threshold (even if some arithmetic is required -- see the profile view). E.g., in the PVD approach just above, you'd have to add 3.8, 1.6, 0.3, and 0.1, or subract 1.3 from 7.1, to get the 5.8 distance from from the threshold to locate CUTSI. Of course, the GPS's with the approach in them will depict the FAF and FEXUX anyway, and those that don't have it will probably have CUTSI in the database, past which you can go 3.8 and then start down from 720 to the MDA.

 

[olasek]

Thanks Ron, your answer is what I would expect, apart from what FAR may say it is also logical. It is amazing however how many pilots think it is illegal.