3 hours ago, sd_flyer said:

Most ILS approaches here in US pretty much retired most of tradition marker beacons system and substituted them with GPS fixes. Yes explicitly GPS is not required and yes some fixes can be identified with cross radials, DME, or ATC radar, but in reality we all load ILS approached into GPS . This is smart way to go!

Understood and mostly agreed.  GPS has been approved in lieu of DME for some years now (though I vaguely recall there were a couple of specific conditions where it's not, I just can't find a reference offhand), but that still doesn't support "everything is provided GPS" and it still doesn't mean they've substituted "GPS fixes"  They're still fixes defined by DME or intersection or... fixes that will be in an up to date GPS DB that your GPS can identify and use.  GPS fixes implies "GPS required" and it's not, unless specified for that approach.  That's the distinction between the two KJAC ILS's.  One has GPS fixes as noted with specific GPS fix symbols on the chart and specifically requires GPS for that reason, and the other does not contain GPS fixes and thus GPS is not required, though may certainly be used to locate those fixes.  But even when the approach has GPS as a requirement, an ILS is still a ground equipment based approach - there is no RNAV overlay, though there is often an RNAV alternative so again "everything" is not provided.  If, for example, the glideslope is out of service it becomes a localizer approach.  You can't just sub in a synthesized LPV glideslope from GPS and pretend it's there, you would instead need to fly the alternate RNAV approach as published if there is one.

I agree that RNAV approaches are wonderful things.  Among other things they can bring ILS-like precision to airports that could never justify the cost and maintenance of an ILS.

Whether it's practical to fly IFR without a GPS in today's world is arguable, but not a point I'm trying to argue.  Were I still actively flying today (I'm not, other than the sim) I certainly wouldn't want to fly IFR without a GPS.  But I could.

 

Scott

Edited September 12, 20241 yr by tttocs

1 hour ago, tttocs said:

Understood and mostly agreed.  GPS has been approved in lieu of DME for some years now (though I vaguely recall there were a couple of specific conditions where it's not, I just can't find a reference offhand), but that still doesn't support "everything is provided GPS" and it still doesn't mean they've substituted "GPS fixes"  They're still fixes defined by DME or intersection or... fixes that will be in an up to date GPS DB that your GPS can identify and use.  GPS fixes implies "GPS required" and it's not, unless specified for that approach.  That's the distinction between the two KJAC ILS's.  One has GPS fixes as noted with specific GPS fix symbols on the chart and specifically requires GPS for that reason, and the other does not contain GPS fixes and thus GPS is not required, though may certainly be used to locate those fixes.  But even when the approach has GPS as a requirement, an ILS is still a ground equipment based approach - there is no RNAV overlay, though there is often an RNAV alternative so again "everything" is not provided.  If, for example, the glideslope is out of service it becomes a localizer approach.  You can't just sub in a synthesized LPV glideslope from GPS and pretend it's there, you would instead need to fly the alternate RNAV approach as published if there is one.

I agree that RNAV approaches are wonderful things.  Among other things they can bring ILS-like precision to airports that could never justify the cost and maintenance of an ILS.

Whether it's practical to fly IFR without a GPS in today's world is arguable, but not a point I'm trying to argue.  Were I still actively flying today (I'm not, other than the sim) I certainly wouldn't want to fly IFR without a GPS.  But I could.

 

Scott

 

I don't know where you get your information! Not some years ago... Effective July 16  of 1998 pilots may substitute IFR certified GPS for DME  and ADF avionics for all operation except NDB approaches without GPS overlay. GPS can be used lieu  for all localizer, VOR DME even those that charted as required equipment ! 

Here some AC that can help https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/946030

Regarding your statement of inoperative glideslope. I'm not sure what do mean by "you can't jus sub  synthesized LPV glideslope"? RNAV approaches are not synthesized they are actually published. Here is one for  KJAC GPS Z 19 approach

https://aeronav.faa.gov/d-tpp/2409/00504RZ19.PDF 

You can see all equipment related minimums LPV, LNAV and circling .

 

P.S. I got my instrument ticket 19 years ago, and as I mentioned there are a lot of thing change since than. I can think of airport now days that wouldn't  have GPS approaches as alternative.

     

6 hours ago, jon b said:

When the controller says maintain 160kts to a five mile final

they are referring to 5 miles out from the runway, phraseology normally used in visual approaches.

13 hours ago, sd_flyer said:

I don't know where you get your information! Not some years ago... Effective July 16  of 1998 pilots may substitute IFR certified GPS for DME  and ADF avionics for all operation except NDB approaches without GPS overlay. GPS can be used lieu  for all localizer, VOR DME even those that charted as required equipment ! 

Here some AC that can help https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/946030

No, an IFR certified GPS may not be substituted for "all" operation.  Final approach segment course guidance still requires reference to the navaid(s) specified in the approach chart.  See para 8b of the referenced AC.

GPS is specifically excluded for use as a substitute for all localizer-based lateral guidance, including back courses (and presumably missed approach course guidance).  See para 8c of the referenced AC.

 

13 hours ago, sd_flyer said:

I don't know where you get your information! Not some years ago... Effective July 16  of 1998 pilots may substitute IFR certified GPS for DME  and ADF avionics for all operation except NDB approaches without GPS overlay. GPS can be used lieu  for all localizer, VOR DME even those that charted as required equipment ! 

Yes, thanks... I'm aware of the regs.  But this AC does not imply that you can substitute GPS entirely to fly an ILS approach.  That's why there ARE RNAV approaches.

 

13 hours ago, sd_flyer said:

Regarding your statement of inoperative glideslope. I'm not sure what do mean by "you can't jus sub  synthesized LPV glideslope"? RNAV approaches are not synthesized they are actually published. Here is one for  KJAC GPS Z 19 approach

You're completely misunderstanding what I was saying.  Yes, I understand that there's a precision GPS approach at KJAC.  But the discussion was about ILS's and my disagreement with you boils down to two statements you've made on the discussion topic.

First: Nowadays everything is provided GPS.

This is the statement I originally took issue with as its simply not true.  You cannot fly an ILS without making use of ground-based localizer and glideslope.  This statement also implies that you couldn't fly an ILS without GPS, which is also not true except in cases like the ILS Z approach at KJAC, where you need BOTH GPS and the localizer and glideslope.

Second: Most ILS approaches here in US pretty much retired most of tradition marker beacons system and substituted them with GPS fixes.

Yes, beacons are all but gone in the US, but they have NOT been substituted with GPS fixes for ILS approaches that do not require GPS, such as the KJAC ILS Y approach.  Yes, you can fly the approach with an approved GPS and up to date database to identify those ground-based fixes in lieu of DME and identifying intersections, but that does not make them GPS fixes.  When they are GPS waypoints as part of an ILS approach, they're clearly identified as such on the approach plate with the star-like symbol, and the plate will specify that GPS is required.  Again, required, but still not sufficient to complete the approach without course reference to the ground-based glideslope and localizer.

 

Scott

1 hour ago, Bob Scott said:

No, an IFR certified GPS may not be substituted for "all" operation.  Final approach segment course guidance still requires reference to the navaid(s) specified in the approach chart.  See para 8b of the referenced AC.

GPS is specifically excluded for use as a substitute for all localizer-based lateral guidance, including back courses (and presumably missed approach course guidance).  See para 8c of the referenced AC.

 

 pilots may substitute IFR-certified GPS receivers for DME and ADF avionics for all operations except NDB approaches without a GPS overlay.

Bob you don't use imaginary GPS approach instead ILS approach! You use your IFR GPS receiver VLOC with overlay of an approach that doesn't have specific GPS overlay otherwise  

 

1 hour ago, tttocs said:

 

First: Nowadays everything is provided GPS.

This is the statement I originally took issue with as its simply not true.  You cannot fly an ILS without making use of ground-based localizer and glideslope.  This statement also implies that you couldn't fly an ILS without GPS, which is also not true except in cases like the ILS Z approach at KJAC, where you need BOTH GPS and the localizer and glideslope.

 

Read my response to Bob. My answer was regarding DME. What you are writing is not what I stated. You can use GPS overlay on ILS approach and don't have to have DME unit instead you can use GPS overlay. I don't know how else to convey my message. Cheez...

Just now, sd_flyer said:

Read my response to Bob. My answer was regarding DME. What you are writing is not what I stated. You can use GPS overlay on ILS approach and don't have to have DME unit instead you can use GPS overlay. I don't know how else to convey my message. Cheez...

But that's not what you said.  You also specifically claimed GPS could substitute for the localizer which is not true.  Nor can it substitute for the glideslope as that is not referenced at all for replacement in the AC.  VLOC is not GPS, it's a mode which reverts your GPS unit to the nav frequency (localizer for ILS) for final guidance.

I think this horse is pretty much on the dead side.

 

Scott

25 minutes ago, tttocs said:

But that's not what you said.  You also specifically claimed GPS could substitute for the localizer which is not true.  Nor can it substitute for the glideslope as that is not referenced at all for replacement in the AC.  VLOC is not GPS, it's a mode which reverts your GPS unit to the nav frequency (localizer for ILS) for final guidance.

I think this horse is pretty much on the dead side.

 

Scott

Where did I say that?

Here gain what I wrote again:

Pilots may substitute IFR-certified GPS receivers for DME and ADF avionics for all operations except NDB approaches without a GPS overlay

GPS can be used lieu  for all localizer, VOR DME even those that charted as required equipment

Again please read what I wrote:

VLOC with overlay of an approach (GPS overlay)

 

 

Here is a quick summary :

Topic Starter : Not all ILS have DME?

ME : Nowdays everything provided by GPS (in regard of DME or fixes)

 

Here is AIM 1.2.7:

c. Uses of Suitable RNAV Systems. Subject to the operating requirements, operators may use a suitable RNAV system in the following ways.

1. Determine aircraft position relative to, or distance from a VOR , TACAN, NDB, compass locator, DME fix; or a named fix defined by a VOR radial, TACAN course, NDB bearing, or compass locator bearing intersecting a VOR or localizer course.

2. Navigate to or from a VOR, TACAN, NDB, or compass locator.

3. Hold over a VOR, TACAN, NDB, compass locator, or DME fix.

4. Fly an arc based upon DME.

 

Now please do tell me if you don't have DME unit installed can you use GPS? Who is beating a dead horse here?

 

1 hour ago, sd_flyer said:

 pilots may substitute IFR-certified GPS receivers for DME and ADF avionics for all operations except NDB approaches without a GPS overlay.

Bob you don't use imaginary GPS approach instead ILS approach! You use your IFR GPS receiver VLOC with overlay of an approach that doesn't have specific GPS overlay otherwise  

 

Not sure what you mean about "imaginary GPS approach".  When the Garmins are in VLOC mode as pictured, then lateral course guidance shown both on the GPS display and that sent to the HSI/CI etc is derived from the VHF nav receiver's signal, not from the GPS receiver.

We may be in violent agreement here, but what you said about use of GPS "in lieu" was somewhat ambiguous.

Bottom line, yes you can use GPS as a substitute means of identifying a fix anywhere, but you may not use it for final approach course guidance on non-RNAV approaches. 

1 hour ago, sd_flyer said:

GPS can be used lieu  for all localizer, VOR DME even those that charted as required equipment

Perhaps what you meant by the above is the GPS can be used in lieu of traditional DME for all localizer, VOR DME ...... , and NOT that GPS can be used in lieu of the localizer signal (lateral guidance) itself.

So, for example, if the localizer is out of service for a particular ILS approach, you can not fly that approach because you have a GPS.

Al

Edited September 13, 20241 yr by ark

7 minutes ago, ark said:

Perhaps what you meant by the above is the GPS can be used in lieu of traditional DME for all localizer, VOR DME ...... , and NOT that GPS can be used in lieu of the localizer signal (lateral guidance) itself.

Al

Of course not instead of localizer signal 

1 minute ago, sd_flyer said:

Of course not instead of localizer signal 

Well, seems to me that has been the crux of the misunderstanding here.

Al

1 hour ago, Bob Scott said:

 

Bottom line, yes you can use GPS as a substitute means of identifying a fix anywhere, but you may not use it for final approach course guidance on non-RNAV approaches. 

Yes of course you still use conventional means on navigation while GPS overlay provide you help  to identify FAF, GS intercept fixes and etc. No need for actual DME unit or cross radials (given that GPS is IFR certified and database is current). 

On 9/12/2024 at 6:38 AM, sd_flyer said:

Nowadays everything is provided GPS.

I think this was the source of all the initial confusion and disagreement. 

Edited September 23, 20241 yr by g-liner