Finding a non GPS IAF into KSNS

Archimago said:
I am not sure but I thought you could not navigate along radials that are used to identify fixes unless they indicate a minimum ifr altitude and distance—transition routes for example
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If they said “cross SNS at 5500, cleared for the approach” you can’t take it upon yourself to do that. But ATC can clear you via the 107 radial with an altitude to maintain until 22 DME
 
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Archimago said:
So to recap the dme arc is left over from a time when the IAF coincided with a route (now decommissioned).
So coming from the south there is no way to find this IAF without gps. Coming from the north it would not make sense to fly out on the radial (plus it’s not indicated as a transition)to the dme arc when you could just fly the procedure turn.
Seems like the arc could be removed from he approach unless it serves some purpose I am missing here
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Technically speaking it should be removed or shortened to start on V248. That might not work though, there is a limit to how short they can be. A dead reckoning segement might work. @aterpster what do you think? Even without doing that it could come in handy for RNAV equipped planes that can navigate direct to the SNS107022 mile fix.
 
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The fix should have been named years ago. Let's call it ACMEE. Then a note could appear by ACMEE: "Radar or approved GPS required for entry at ACMEE."
 
aterpster said:
The fix should have been named years ago. Let's call it ACMEE. Then a note could appear by ACMEE: "Radar or approved GPS required for entry at ACMEE."
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Yeah, but let’s say they decide to fix it now and put an ‘ACMEE’ on V248. Does that make the Arc to short to use? If so, do you see a reason not to use a dead reckoning segment? @Archimago , there are a couple of these close to you. Look at FRAMS CREPE on the ILS and LOC approaches at KSBP.
 
ateamer said:
It’s probably all moot. Every time I’ve flown the Salinas ILS, it was vectors no matter where we started from.
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It's moot until that day you fly somewhere, ask for vectors, are told "unable" and have no idea what to do. I have seen an awful lot of "Understanding Approach Plates 101" questions online and off.
 
luvflyin said:
You could get direct UAD. If you don’t have ADF you go to SNS then the Feeder Route to UAD. You’ll need DME to do that.
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How do you fly the feeder route without ADF? (I assume no GPS, either, otherwise you could substitute the GPS for the ADF, correct?) The feeder route says 5500 to UAD NDB 132. Does that not require the to fly out on the UAD NDB radial? Why it does not use the VOR radial, I don't know. But that's what it says.

Edit: that was supposed to say "without ADF."
 
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aterpster said:
I suspect that is a Jeppesen convention, not an ICAO convention. Can't verify with the Mexico IAP, though. It's closed expect to big bucks subscribers.
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Basically, it's a CNF. On the KSNS approach, it's identified that way in a GTN using either the Jepp or the Garmin database. Could it be a database convention with a chartmaker decision whether to depict it on the chart?

Edit: apparently there was an FAA Charting Forum discussion back in 2012 whether to place CNFs on the plate at all, with some saying it was potentially distracting to pilots who were not flying GPS. I did't look into it that deeply but I can imagine a compromise i which, if the fix was otherwise identifiable with traditional navaids (like R107, 22 DME) it would not be shown on the chart but only in a GPS database where it meant something. Jepp, of course is not bound by FAA charting conventions.
 
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Archimago said:
I don't have ADF but do have DME. If I get cleared for SNS, how would I turn to go outbound? I see the procedure turn that brings me inbound but how would I turn the nearly 360 ish degrees at SNS to get me out to turn back in.
If I went to SNS, what is the purpose of the DME arc? Sorry, student pilot here, so its a little fuzzy for me
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The intersection of the DME arc and the 107 radial off of the SNS VOR is a second IAF. You don't fly the procedure turn if you are flying the DME arc. You only fly the procedure turn if you are cleared to UAD and need to turn around, for example, if you are cleared to SNS, then to UAD to start the procedure.
 
PPC1052 said:
How do you fly the feeder route with ADF? (I assume no GPS, either, otherwise you could substitute the GPS for the ADF, correct?) The feeder route says 5500 to UAD NDB 132. Does that not require the to fly out on the UAD NDB radial? Why it does not use the VOR radial, I don't know. But that's what it says.
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There’s nothing on the chart to indicate which VOR radial UAD is on...you’d have to navigate by ADF (or intercept the localizer). If you’re flying the feeder, you’d maintain 5500 outbound to UAD. you could also probably get clearance to fly a random bearing to the NDB once you’re within its service volume at a higher altitude and use a holding pattern on the inbound localizer course at UAD for any additional descent you may need.
 
MauleSkinner said:
There’s nothing on the chart to indicate which VOR radial UAD is on...you’d have to navigate by ADF (or intercept the localizer). If you’re flying the feeder, you’d maintain 5500 outbound to UAD. you could also probably get clearance to fly a random bearing to the NDB once you’re within its service volume at a higher altitude and use a holding pattern on the inbound localizer course at UAD for any additional descent you may need.
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I had an error in my first post. It meant to say, "How do you fly the feeder route without ADF?" Kind of changes the meaning a bit. Sorry.

As I read the chart, the feeder route requires flying the ADF radial, not the VOR radial. That was the point I was trying to make.
 
PPC1052 said:
How do you fly the feeder route with ADF? (I assume no GPS, either, otherwise you could substitute the GPS for the ADF, correct?) The feeder route says 5500 to UAD NDB 132. Does that not require the to fly out on the UAD NDB radial? Why it does not use the VOR radial, I don't know. But that's what it says.
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NDB’s don’t have radials. It’s course to or bearing from. This would be the 132 course to UAD. Once you cross SNS you won’t need the VOR again for anything until the missed approach. Using the Localizer would be the easiest way to do it but the approach is constructed based on not using the Localizer until intercepting it inbound.
 
PPC1052 said:
I had an error in my first post. It meant to say, "How do you fly the feeder route without ADF?" Kind of changes the meaning a bit. Sorry.

As I read the chart, the feeder route requires flying the ADF radial, not the VOR radial. That was the point I was trying to make.
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Ok...you could use the localizer to get there with DME to identify distance.
 
The 132 degrees on the feeder route is a VOR radial. I don't see anything on the chart to prevent you from flying that radial, using the DME distance provided to tell you when you reach the IAF. (The outbound course on the localizer is 131 degrees, not 132. UAD is just the identifier of the fix that you are flying to.)

Take a look at the Red Bluff VOR/DME Rwy 13 approach for comparison. That feeder route has the exact same depiction as the one at Salinas, with no co-located NDB or localizer to confuse the issue.

RBL 00344VD15.png
 
I wrote in about this a couple of years ago. Let me share the response.....

ILS RWY 31 Salinas (SNS)

Hello,

Thank you for your time.

With regards to the SNS ILS RWY 31 approach chart, I am having difficulty identifying the IAF where SNS R-107 meets the ARC at SNS 22NM. I am inquiring in case it was inadvertently omitted from the chart. I also do not see it on the low altitude chart, L3.

Unless it just means to proceed via SNS R-107 and commence the ARC at 22 NM.

Thank you,
Noah Fong
CFI-A, CFI-I, MEI, ATP

Control Number 28976 has been assigned to this issue for tracking purposes.
This concern has been closed with the following Response:

Noah,

This is a very old procedure, but I do think that is what it means. The reason why I say this is because the IAF would have had a Unnamed DME fix or a Named DME fix to help and 1992 forms imply that. Here is what is written on the forms terminal routes;

FROM TO COURSE AND DISTANCE
R-107 SNS VORTAC CW (IAF) to 1-SNS LOC CRS (NoPT), 22 DME ARC (SNS LR-124)

I'm going to add a former flight inspection pilot to this email to give you a clarification. Thank you for the inquiry.

Regards,

Marlon Robinson
Manager

On Tue, Jul 31, 2018 at 11:53 AM, <roy.f.turner@faa.gov> wrote:

Mr Fong,

The SNS R-107 is not a route, it only marks the beginning of the 22 DME arc, which is one of two initial approach segments (the DME arc and the PT). When this procedure was developed, the beginning of the DME arc did not require a named fix. In order to transition from the enroute structure, radar vectors are required to intercept the DME arc between the SNS R-107 and R-124. because a nonradar transition to intercept the DME arc is not available, the feeder from SNS VORTAC to the UAD NDB (and subsequent procedure turn) satisfies the requirement for a nonradar transition. Otherwise, “Radar Required” would be on the plan view.

Since then, this procedure has been reworked to delete the DME arc and take into account that the NDB has been decommissioned. It combines the ILS and LOC/DME into one approach with both types of minimums. A nonradar transition is provided by the BSR VORTAC. Estimated publication date is 9/13/2018.

Hope this helps. If you have further questions, you may contact me at roy.f.turner@faa.gov.

Thanks!

Roy F Turner
Aeronautical Information Services
QC Sub-Team A
AJV-5441
 
Looks like that estimated publication date was a little off. ;)
 
Palmpilot said:
The 132 degrees on the feeder route is a VOR radial. I don't see anything on the chart to prevent you from flying that radial, using the DME distance provided to tell you when you reach the IAF. (The outbound course on the localizer is 131 degrees, not 132. UAD is just the identifier of the fix that you are flying to.)

Take a look at the Red Bluff VOR/DME Rwy 13 approach for comparison. That feeder route has the exact same depiction as the one at Salinas, with no co-located NDB or localizer to confuse the issue.

View attachment 92455
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I do not have an answer in this one but one difference is that in the SNS plate the transition is to an NDB, not to a fix defined by DME off the VOR.
 
midlifeflyer said:
I do not have an answer in this one but one difference is that in the SNS plate the transition is to an NDB, not to a fix defined by DME off the VOR.
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It is defined by DME, you can see that on the profile view. SNS 12.1 DME can be used to call the FAF. But SNS radials have nothing to do with it. The Feeder transition from SNS is a ‘course to’ the UAD NDB, not a radial from SNS like you said. If there was no SNS VOR but there was an airway passing directly over that spot, the Feeder could be there. It would be from a fix there and the 132 course to UAD. It would look the same on the Chart. 5500 to UAD NDB 132{degree symbol} (12.1). It would use NDB criteria for obstruction clearance, not VOR. In that short a distance there probably wouldn’t be much difference. SNS radials of course could provide good assistance in flying the ‘course to’ if you get a little behind the ADF. Academic discussion seeing as how UAD has been decommissioned.

EDIT: Or maybe not. https://www.faa.gov/aero_docs/acifp/NDBR/2014052728343401001-SNS-NDBR/CA_SNS_I31_AMDT 5.pdf
 
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luvflyin said:
It is defined by DME, you can see that on the profile view. SNS 12.1 DME can be used to call the FAF. But SNS radials have nothing to do with it. The Feeder transition from SNS is a ‘course to’ the UAD NDB, not a radial from SNS like you said. If there was no SNS VOR but there was an airway passing directly over that spot, the Feeder could be there. It would be from a fix there and the 132 course to UAD. It would look the same on the Chart. 5500 to UAD NDB 132{degree symbol} (12.1). It would use NDB criteria for obstruction clearance, not VOR. In that short a distance there probably wouldn’t be much difference. SNS radials of course could provide good assistance in flying the ‘course to’ if you get a little behind the ADF. Academic discussion seeing as how UAD has been decommissioned.
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Looking at source on the IFP Gateway, the feeder route is ambiguous as to whether it is a bearing to the (now non-existent) NDB,, or whether is the SNS R-132. The procedure has been very poorly maintained.
 
aterpster said:
My guess is that they weren't naming DME fixes when this IAP was designed. Should they have named it during a periodic review? Beats me. Russ would know.
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I see that @noahfong posted his direct reply from the FAA, which pretty much is what I was going to respond with.

Using publicly accessible information at the FAA's IFP Gateway, https://www.faa.gov/air_traffic/fli....results&tab=ndbr&nasrId=SNS#searchResultsTop

I see the procedure had its last "full" amendment, amendment 5, in 1992.

At that time, Radial/DME fixes did not have to be named, as far as I am aware.

Since then it has had five "abbreviated" amendments, 5A - 5E.
5A (1999) - adjusted Circling minimums
5B (2006) - updated TDZE and DA, added the note "ADF or DME required"
5C (2008) - deleted LOC minimums and some other things
5D (2010) - deleted circling minimums
5E (2014) - deleted the MACAM OM.

There is indeed an ILS OR LOC RWY 31, Amdt 6 that is available for review on the Coordination tab, but that's what was supposed to have been published in 2018. There is no indication on the website as to what happened to it, or whether the amendment has simply been delayed or terminated.
 
midlifeflyer said:
I do not have an answer in this one but one difference is that in the SNS plate the transition is to an NDB, not to a fix defined by DME off the VOR.
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But it is defined by DME off the VOR. The DME distance is given in two places on the SNS chart: once in the data block for the feeder route, and once underneath the data block for UAD. Why would they put that there if it wasn't OK to use it to identify the IAF?

What we have there is a route segment with a VORTAC on one end and a (now decommissioned) NDB on the other. Even when the NDB was operational, I don't see why it would not have been within the pilot's discretion to use either one navaid or the other to fly that route segment. The entire 12.1 NM is well within the service volume of the VOR.
 
Palmpilot said:
But it is defined by DME off the VOR. The DME distance is given in two places on the SNS chart: once in the data block for the feeder route, and once underneath the data block for UAD. Why would they put that there if it wasn't OK to use it to identify the IAF?

What we have there is a route segment with a VORTAC on one end and a (now decommissioned) NDB on the other. Even when the NDB was operational, I don't see why it would not have been within the pilot's discretion to use either one navaid or the other to fly that route segment. The entire 12.1 NM is well within the service volume of the VOR.
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It does seem that’s the intent.
https://www.faa.gov/aero_docs/acifp/NDBR/2014052728343401001-SNS-NDBR/CA_SNS_I31_AMDT 5.pdf
 
Palmpilot said:
But it is defined by DME off the VOR. The DME distance is given in two places on the SNS chart: once in the data block for the feeder route, and once underneath the data block for UAD. Why would they put that there if it wasn't OK to use it to identify the IAF?

What we have there is a route segment with a VORTAC on one end and a (now decommissioned) NDB on the other. Even when the NDB was operational, I don't see why it would not have been within the pilot's discretion to use either one navaid or the other to fly that route segment. The entire 12.1 NM is well within the service volume of the VOR.
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Looking at it closer, I agree.
 
midlifeflyer said:
So I guess he was right about that naming convention.
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More on naming convention. Here are the plan views for ILS Z 13L at Bogota, Colombia. Unlike Mexico, Colombia's AIP is open to all. Note "D269E" on the Jepp chart and in a Garmin navigator. "D269E" is not on source.

SKBO.jpg
 
Palmpilot said:
...The DME distance is given in two places on the SNS chart: once in the data block for the feeder route, and once underneath the data block for UAD....
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Looking at it again this morning, I see a third place that the DME of the IAF is depicted: on the profile view.
 

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aterpster said:
More on naming convention. Here are the plan views for ILS Z 13L at Bogota, Colombia. Unlike Mexico, Colombia's AIP is open to all. Note "D269E" on the Jepp chart and in a Garmin navigator. "D269E" is not on source.
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I think it is clearly a database convention for unnamed DME fixes. I can even go to one in SkyVector. But it's not a source function or in the FAA waypoint database like other CNFs. As the #1 aviation data provider, would not be surprised if it it was initiated by Jepp although I guess it could have been somewhere else.
 
midlifeflyer said:
I think it is clearly a database convention for unnamed DME fixes. I can even go to one in SkyVector. But it's not a source function or in the FAA waypoint database like other CNFs. As the #1 aviation data provider, would not be surprised if it it was initiated by Jepp although I guess it could have been somewhere else.
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To give the devil his due, they are the only chart vendor that charts every IFR airport in the world. BTW, I just worked with a current Jepp chart that says "Not Applicable" for CAT D minimums. Stay tuned. :)
 
Palmpilot said:
Looking at it again this morning, I see a third place that the DME of the IAF is depicted: on the profile view.
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Palmpilot said:
Looking at it again this morning, I see a third place that the DME of the IAF is depicted: on the profile view.
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I just noticed the one under the CHUALAR box, missed it before. But that makes it two, not three DME depictions. The (12.1) in 5500 to UAD NDB 132 (12.1) would be there even if there was no DME. Segments have their length depicted like that whether there is DME or not.
 
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