Author Topic: DME or RADAR required, no DME, radar fix callouts required on ILS?  (Read 31174 times)

Offline buzzin77

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Quick question for tower or maybe TRACON...

I sometimes fly /G planes that don't always get their databases updated promptly. This leaves me without a DME substitute, and file /U.

On an ILS approach (that is an ILS or LOC RWY X procedure but NOT ILS or LOC DME) that says "DME or radar required" in the notes, the approach controller tells me where I am in relation to the LOC FAF. If I am flying the ILS approach, do I need to ask the tower controller to tell me when I have arrived at the next fix, since I don't have DME, or is that only necessary if I'm flying the LOC approach to get the last step down?

For an example see the San Diego, CA Montgomery Field ILS or LOC RWY 28R. The last fix would be PALOS.
What's a tidy way of requesting the controller to ID the fix for me? "No DME, request radar fix callouts?"



Offline Jason

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #1 on: December 02, 2012, 10:20:32 PM »
What type of GPS? You can still substitute GPS in lieu of DME and file /G with an expired database as long as you verify that the data is still correct (fixes/waypoints haven't been removed or relocated).

Some AFM supplements even allow you to conduct GPS approaches with an expired database as long as you verify the database expiration date falls after the effective date on the approach chart (in other words, the database expired after the approach chart was last amended)... however that is aircraft/AFM specific.

That being said... to answer your question, yes, you would have to request radar callouts for the respective fixes on the approach.

Offline sykocus

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #2 on: December 03, 2012, 05:03:25 PM »
To answer you question I would say something along the lines of "N123 needs PENYY and PALOS to be called for us". I would do it around the time you get cleared for the approach as the tower may not have a certified radar display and wouldn't be able to do it and the approach controller would have to do it and coordinate hold on to you well inside the tower's class D.

I did have a few thoughts/questions and I don't mean them to be confrontational or rhetorical. If you were doing the ILS you mentioned why do you need to know you are over PALOS? You would have the GS to give you vertical guidance and I wouldn't think the crossing restriction would matter as long as you were in the middle of the GS. I can see if the GS was out leaving you only with the LOC approach and and no vertical guidance. Also (this might be along the lines of what Jason was asking), are you not able to use the GPS to see when you 3.6 miles from the threshold? If I understood correctly the gps is still usable to tell you where you are, it's just the the data regarding fixes and procedures may not be the most up to date.
« Last Edit: December 03, 2012, 05:05:15 PM by sykocus »

Offline Jason

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #3 on: December 03, 2012, 09:46:32 PM »
If you were doing the ILS you mentioned why do you need to know you are over PALOS? You would have the GS to give you vertical guidance and I wouldn't think the crossing restriction would matter as long as you were in the middle of the GS.

The stepdown altitude at PALOS is only part of the LOC procedure.
« Last Edit: December 03, 2012, 09:48:53 PM by Jason »

Offline buzzin77

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #4 on: December 08, 2012, 12:36:42 AM »

I did have a few thoughts/questions and I don't mean them to be confrontational or rhetorical. If you were doing the ILS you mentioned why do you need to know you are over PALOS?

No, that's helpful, thanks. That's what I was curious about. On the plate, there is no asterisk next to PALOS in the profile view with a note that says "LOC only," like there is next to the visual descent point. There is, however, an asterisk next to the step down altitude of 1380. As the pilot flying the ILS approach, I don't need to know when I reach PALOS, I just follow the GS like you said. I guess it's just hard to make two approaches on one plate without having at least some confusion!

Follow up question: Approach may tell me: "You are 1 mile from PENYY, turn left heading XXX to join the localizer, maintain X,XXX until established...etc."
Does "1 mile from PENYY" count as a radar callout, or would it have to be right over the fix?



What type of GPS?

It varies between a Garmin G430 only 1 cycle out of date, sometimes a Bendix King KLN89B or 94, and one of those never gets updated. That's interesting about the AFM supplement, I hadn't thought to look there. Thanks for that.

are you not able to use the GPS to see when you 3.6 miles from the threshold? If I understood correctly the gps is still usable to tell you where you are, it's just the the data regarding fixes and procedures may not be the most up to date.

Yes that's correct, as long as the fixes haven't changed on the plate since the GPS was updated, I can tell.  Although the GPS is a little different and maybe confusing too, in that it measures the distances between fixes, but not to the DME equipment. So PALOS at 3.6 DME is 2.9 from the threshold.


Offline sykocus

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #5 on: December 08, 2012, 03:23:39 AM »

Follow up question: Approach may tell me: "You are 1 mile from PENYY, turn left heading XXX to join the localizer, maintain X,XXX until established...etc."
Does "1 mile from PENYY" count as a radar callout, or would it have to be right over the fix?

I would say no. When you are being vectored to the final approach course you are told the distance from the FAF because that's the requirement for being vectored to final. When you are told you are over the FAF it's because it's a radar derived fix and you need to be told when you are over it. So they are satisfying different requirements. Also the 7110.65 says a pilot needs to be advised when over a radar derived fix not simply their distance from it. In fact there the example would support that they need to be done at separate times. "EXAMPLE−
“Three miles from final approach fix. Turn left heading
zero one zero. Maintain two thousand until established on
the localizer. Cleared I−L−S runway three six approach. I
will advise when over the fix.”"

FWIW in the section of the 7110.65 that talks about that and it doesn't mention anything about calling a radar derived fix other then the FAF. http://www.faa.gov/air_traffic/publications/atpubs/atc/atc0509.html#atc0509.html.5

Although the GPS is a little different and maybe confusing too, in that it measures the distances between fixes, but not to the DME equipment. So PALOS at 3.6 DME is 2.9 from the threshold.

That's my fault I misspoke. The DME is off the LOC and the LOC is located the the departure end of the runway so you you'd have add the runway length (.75 of a nm) to the distance from the threshold to get the DME distance. 2.9+.75=3.6 (rounding down). The helpful thing would be if you could program the GPS to give you the milage from I-MYF (the ID for the ILS) that way you wouldn't have to do any math.

Offline Jason

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #6 on: December 08, 2012, 02:27:45 PM »
That's my fault I misspoke. The DME is off the LOC and the LOC is located the the departure end of the runway so you you'd have add the runway length (.75 of a nm) to the distance from the threshold to get the DME distance. 2.9+.75=3.6 (rounding down). The helpful thing would be if you could program the GPS to give you the milage from I-MYF (the ID for the ILS) that way you wouldn't have to do any math.

I would just load the approach in the database and verify that the fixes haven't been relocated or deleted. Then use along-track-distance (ATD) to identify each fix as you normally would. You can still substitute GPS in lieu of DME with an expired database.

Offline sykocus

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #7 on: December 08, 2012, 04:50:46 PM »
That's my fault I misspoke. The DME is off the LOC and the LOC is located the the departure end of the runway so you you'd have add the runway length (.75 of a nm) to the distance from the threshold to get the DME distance. 2.9+.75=3.6 (rounding down). The helpful thing would be if you could program the GPS to give you the milage from I-MYF (the ID for the ILS) that way you wouldn't have to do any math.

I would just load the approach in the database and verify that the fixes haven't been relocated or deleted. Then use along-track-distance (ATD) to identify each fix as you normally would. You can still substitute GPS in lieu of DME with an expired database.

I was thinking if the that specific approach is not in the database or is out of date. Would what I said still be suitable in place of DME?

Offline Jason

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #8 on: December 08, 2012, 05:56:24 PM »
I was thinking if the that specific approach is not in the database or is out of date. Would what I said still be suitable in place of DME?

It works but since there is rounding involved I tend to stay away from methods like that.

Offline frusa

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Re: DME or RADAR required, no DME, radar fix callouts required on ILS?
« Reply #9 on: May 12, 2015, 12:41:41 AM »
The Tower Radar display at MYF is certified. We are required to call the fix if required per Order 7110.65V para 5-1-12a.