IAF, IF, Radar Required, Radar Fix, PT, DME, etc

I thought this was going to be a cheer, and was wondering how you were going to rhyme it.
 
Anything in particular you would like to discuss?
 
Ryan F. said:
Anything in particular you would like to discuss?
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The Radar Required note at SARGS. I’ve never seen that before. It’s not a Radar Fix. The PT requiring DME. Never seen that either. SARGS being an IF instead of an IAF.
 
It's messy, if you ask me. Interesting though. At first blush, the IF (SARGS) applies to straight-ins under radar control. The PT is off GATTO (Jepp shows it, but w/o the usual straight leg). I guess they want to clear folks direct to the IF when using radar. Jepp must have tried to make it more accurately depicted, yet managed to throw in their own version of confusing depictions.
 
dtuuri said:
It's messy, if you ask me. Interesting though. At first blush, the IF (SARGS) applies to straight-ins under radar control. The PT is off GATTO (Jepp shows it, but w/o the usual straight leg). I guess they want to clear folks direct to the IF when using radar. Jepp must have tried to make it more accurately depicted, yet managed to throw in their own version of confusing depictions.
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I can see them giving RNAV planes direct SARGS. A lot. And they must have Radar to do that. And clearing RNAV planes direct is done thousands of times a day everywhere. But I can’t see any reason to put Radar Required on the Chart. Have you ever seen this on a Chart before?
 
luvflyin said:
The Radar Required note at SARGS. I’ve never seen that before. It’s not a Radar Fix. The PT requiring DME. Never seen that either. SARGS being an IF instead of an IAF.
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PT does not require DME, but it is helpful. Cross radial from MZB and the localizer defines GATTO. Although V165 southbound leads to SARGS, there is no IAF that leads to it. There are many examples when ATC does not want a procedure to joined using own navigation, for example my home drome KUZA RNAV(GPS) Rwy 20 used to have an IAF/IF and an HILPT at CESOX, but ATC did not want aircraft flying the hold because it is only 2 NM from the main runway at KCLT. So when vectors only are desired for an approach, the procedure can begin with an IF.
 
luvflyin said:
I can see them giving RNAV planes direct SARGS. A lot. And they must have Radar to do that. And clearing RNAV planes direct is done thousands of times a day everywhere. But I can’t see any reason to put Radar Required on the Chart. Have you ever seen this on a Chart before?
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Is this ok? Radar required to enter unless you have GPS. No PT, though. Like in the OP, radar isn't required to fly the approach.
05027IL24 (skyvector.com)
 
John Collins said:
PT does not require DME, but it is helpful.
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Well, it is noted that it is required, so that is enough for me. Why? So SARGS can be an IF on the inbound leg for separation purposes, I imagine. You need DME to assure you go out enough during the PT to comply. Possible trouble is, SARGS is 4.1 NM from GATTO. Only 5.9 NM left to turn around. Ought to be enough, though.
 
John Collins said:
PT does not require DME, but it is helpful. Cross radial from MZB and the localizer defines GATTO. Although V165 southbound leads to SARGS, there is no IAF that leads to it. There are many examples when ATC does not want a procedure to joined using own navigation, for example my home drome KUZA RNAV(GPS) Rwy 20 used to have an IAF/IF and an HILPT at CESOX, but ATC did not want aircraft flying the hold because it is only 2 NM from the main runway at KCLT. So when vectors only are desired for an approach, the procedure can begin with an IF.
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On this Approach DME is required. That’s what the Chart says. That’s what has me scratching my head and asking questions. Have you seen it before.
 
dtuuri said:
Well, it is noted that it is required, so that is enough for me. Why? So SARGS can be an IF on the inbound leg for separation purposes, I imagine. You need DME to assure you go out enough during the PT to comply. Possible trouble is, SARGS is 4.1 NM from GATTO. Only 5.9 NM left to turn around. Ought to be enough, though.
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The PT is Remain within 10 NM. SARGS has nothing to do with PT even though it is geographically coincident with the Localizer. You could fly the PT in a slower airplane and never get beyond SARGS. When flying the PT you can just pretend SARGS doesn’t exist.
 
luvflyin said:
You could fly the PT in a slower airplane and never get beyond SARGS.
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This is why you need to heed SARGS, imo, and therefore must have DME. They must want "final" to be at least as long as SARGS is from the runway, for whatever reason. I.e., you're caught between a rock (SARGS) and a hard place (10 NM from GATTO), so need a DME.
 
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dtuuri said:
Well, it is noted that it is required, so that is enough for me. Why? So SARGS can be an IF on the inbound leg for separation purposes, I imagine. You need DME to assure you go out enough during the PT to comply. Possible trouble is, SARGS is 4.1 NM from GATTO. Only 5.9 NM left to turn around. Ought to be enough, though.
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The DME location is noted on the chart, but should not be a requirement since the cross radial is also charted to define the fix. The fix is defined in the eNASR data as a radial and localizer. The FAA 8260-3 source does not say to chart the note, which makes the FAA chart plan view note an error, the Jeppesen version matches the source. I will report the error to the FAA.

I suspect the Radar requirement to join the approach is an ATC requirement and not driven by navigation as it is on the airway V165 and can be navigated to southbound on the airway with or without GPS. That is my guess for why it is not an IAF.
 
This is above my pay grade but the first question I ask when confronted with something like this is, "how would I fly it with a single VLOC radio and no GPS?"
 
John Collins said:
The DME location is noted on the chart, but should not be a requirement since the cross radial is also charted to define the fix. The fix is defined in the eNASR data as a radial and localizer. The FAA 8260-3 source does not say to chart the note, which makes the FAA chart plan view note an error, the Jeppesen version matches the source. I will report the error to the FAA.
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?
Yes it does.
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And I see both notes on the Jepp chart.

Are you looking at something different?
 
dtuuri said:
This is why you need to heed SARGS, imo, and therefore must have DME. They must want "final" to be at least as long as SARGS is from the runway, for whatever reason. I.e., you're caught between a rock (SARGS) and a hard place (10 NM from GATTO), so need a DME.
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Could be. Nothing surprises me anymore. But I really don’t think that’s it. If SARGS was associated with the PT, it would be in the Profile View.
 
luvflyin said:
Could be. Nothing surprises me anymore. But I really don’t think that’s it. If SARGS was associated with the PT, it would be in the Profile View.
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I think you are right about that. The PT is within 10 NN of GATTO. SARGS is only 4.1 from GATTO. I was thinking it had something to do with the ability to identify both the OCN radial and the localizer at the same time, but I'm probably wrong.
 
midlifeflyer said:
This is above my pay grade but the first question I ask when confronted with something like this is, "how would I fly it with a single VLOC radio and no GPS?"
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Hmm. This one’s not as busy as some I’ve seen. But maybe you’ve hit on something. If there wasn’t Radar then you’d be on airways. Like V165 SARGS. MZB V165 would be undoable without a PT at SARGS, probably a HILPT. REDEN V165 SARGS would work. But that could be a little dicey if you were flying pretty fast. I forget the math, how wide is the Localizer signal there peg to peg? Maybe that’s why the Radar Required.
 
midlifeflyer said:
I think you are right about that. The PT is within 10 NN of GATTO. SARGS is only 4.1 from GATTO. I was thinking it had something to do with the ability to identify both the OCN radial and the localizer at the same time, but I'm probably wrong.
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I think I may have it figured out. There are 2 Holding Patterns at SARGS. West on the MZB 255 radial and West on the I-SAN Localizer. They aren’t Charted on the Approach or Enroute Charts. The MZB 255 radial one is Charted on the SHAMU ONE Arrival. The Holding Patterns are not clear of W-291. There is Letter of Agreement between Socal Tracon and the Navy about their use. I figure the Navy says it’s ok to use them as long as Socal uses Radar to monitor it. I’d guess the GATTO PT, remain within 10 nm, is very close to W-291 and the Navy is guarding against pilots getting sloppy with how they figure out where 10 miles is. So they demand using DME. I don’t see any documentation of that though in the Radio Fix and Holding Data Records. The SARGS thing is documented there. https://www.faa.gov/air_traffic/flight_info/aeronav/aero_data/Radio_Fix_Holding_8260/

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