Approach Plate Drafting question

aterpster said:
Neither MUDBE nor FAXAG are intersections...................
roncachamp said:
FAXAG is not an intersection.
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I've been going over this thread and this is it an intersection thing keeps bugging me. I get it that there depiction on the final approach course is intended to be DME because of the inaccuracies of using cross radials to determine when to begin descent to lower altitudes. But I have to argue that there is an intersection out there. Let's fly it. For now I'm going to use the 035 radial from VHP to FAXAG because that's what the Jep chart says and the Gov chart implies.

Cross Brickyard at 3000, cleared for the localizer runway 21 approach. Ya cross VHP, twist to 035. I-EYE is dialed in the other Nav, identified and ya remind yourself one more time your going to have reverse sensing. Are you going to turn outbound into the HILPT at 14.6 DME regardless of where the needle is on the localizer? When is that needle going to start moving? Is the VHP 035 a little off? Just gotta be +/- 4 degrees for the Nav in the plane to be ok. The approach builders used +/- 4.5 (I think, maybe it's different for this.) Maybe you actually intersect the localizer outside of FAXAG. How far out? That's a pretty narrow angle.

etc, etc
 
luvflyin said:
I've been going over this thread and this is it an intersection thing keeps bugging me. I get it that there depiction on the final approach course is intended to be DME because of the inaccuracies of using cross radials to determine when to begin descent to lower altitudes. But I have to argue that there is an intersection out there. Let's fly it. For now I'm going to use the 035 radial from VHP to FAXAG because that's what the Jep chart says and the Gov chart implies.

Cross Brickyard at 3000, cleared for the localizer runway 21 approach. Ya cross VHP, twist to 035. I-EYE is dialed in the other Nav, identified and ya remind yourself one more time your going to have reverse sensing. Are you going to turn outbound into the HILPT at 14.6 DME regardless of where the needle is on the localizer? When is that needle going to start moving? Is the VHP 035 a little off? Just gotta be +/- 4 degrees for the Nav in the plane to be ok. The approach builders used +/- 4.5 (I think, maybe it's different for this.) Maybe you actually intersect the localizer outside of FAXAG. How far out? That's a pretty narrow angle.

etc, etc
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When you fly the VHP to FAXAG feeder route you are going to intercept the HILPT somewhere within its confines. Then, when flying the holding pattern your holding fix is the IEYE LOC and the VHP 14.6 DME.
 
luvflyin said:
Yeah. I think the Note Box being just informational is not it. Things like you need to raise the minimums when the altimeter source is remote and therefore less accurate is pretty important stuff.
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I didn't write my prior post well. I didn't mean that I had to go digging to find what the notes mean. I meant that I had to go digging to find out what different information is intended to be communicated to the pilot by the drafters as a result of identifying the required equipment in the different locations on the approach plate. Sorry for my poor drafting.
 
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luvflyin said:
And why is it not a LOC/DME approach. If it is a LOC that requires DME doesn't that by default make it a LOC/DME approach?
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Good question. This is the point I am really getting at. If it's required for the approach, it doesn't really matter to the pilot flying which portion it's necessary. Why not put it right out there for easy digestion.
 
PPC1052 said:
Good question. This is the point I am really getting at. If it's required for the approach, it doesn't really matter to the pilot flying which portion it's necessary. Why not put it right out there for easy digestion.
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The placement of notes indeed sucks. For example when radar is required for procedure entry the FAA charts have a shouting RADAR REQUIRED note in the plan view. They must, because of IACC charting specs. Jeppesen is not bound by IACC specs so they place the note in the briefing strip without the shouting.
 
The VHP 042 radial is being removed from the approach chart in June.
 
PPC1052 said:
I didn't write my prior post well. I didn't mean that I had to go digging to find what the notes mean. I meant that I had to go digging to find out what different information is intended to be communicated to the pilot by the drafters as a result of identifying the required equipment in the different locations on the approach plate. Sorry for my poor drafting.
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No poor drafting. I thought it was a well put and important question. The note box being just informational was put forth by midlifeflyer to get the discussion kickstarted. I guess I didn't really mean to quote your post.
 
aterpster said:
When you fly the VHP to FAXAG feeder route you are going to intercept the HILPT somewhere within its confines. Then, when flying the holding pattern your holding fix is the IEYE LOC and the VHP 14.6 DME.
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Makes sense. Depending on how big, or maybe it would be better to say "how long" FAXAG is, it should be easy enough to get your course reversed and established on the localizer inbound in time to fly over FAXAG inbound and begin your descent. But you may not be able to do that if you took the HILPT to be a "one minute" pattern. You could "intersect" the localizer somewhere inside of FAXAG's actual location and have to fly outbound a bit longer to give yourself time to get the reversal done and the needle at least moving, if not centered before you got back to FAXAG inbound. I wouldn't even consider doing a parallel entry on this approach. I'd like to know just how long a space along the localizer is covered when you are intercepting it from a VHP radial. In other words, you are flying the VHP radial outbound waiting for the needle to move on the localizer to begin your outbound leg. IF you were dead centered on the VHP radial that would of course be over FAXAG. But if your not dead centered it would be either inside or outside of FAXAG. No big deal really, once you get the localizer and start outbound you should be using DME to "time" things from then on. If your inside, just wait until 14.6 to begin the HILPT. If it happens outside, just get going on it now and get it done.
I don't know trigonometry well enough to do it, but I'd like to see just how "long" the "outbound FAXAG" could be. A little instrument error is going to move it. A little eyeball error when you dial it into the OBS is going to move it. I think the proper outbound radial from VHP is really the 041 as the GOV chart first implies on the feeder route. Not the 035 that continues in a thin line to FAXAG, I think the Jepp folks got their 035 from that.
 
Going over this whole thread again, ronachamp's post #29 reached out and slapped me right upside the head. It's all there. Feeder routes not being authorized to terminate on localizers. FAXAG officially being identified as only a Lat/Long coordinate.

Just flying the radial outbound from VHP waiting for the localizer needle to move and then finding yourself somewhere within the confines of the HILPT and taking it from there doesn't cut it. This Approach should be NOTAM'd down now.
 
luvflyin said:
Feeder routes not being authorized to terminate on localizers.
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I am not sure that is what he is saying at all. I think his point is only that FAXAG is a fix, not an intersection. The significance being that you cannot identify FAXAG by the cross radial because it's too acute. Instead, it must be identified by the DME distance on the localizer.

luvflyin said:
Just flying the radial outbound from VHP waiting for the localizer needle to move and then finding yourself somewhere within the confines of the HILPT and taking it from there doesn't cut it. This Approach should be NOTAM'd down now.
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I'm not sure that follows, either. There is tremendously more error permitted for IAF procedure entry than for FAF location. Here's a nice little primer: http://www.google.com/url?sa=t&rct=...QcOUwg5EZGfrno_gQ&sig2=ktmUGvuhB-Cr0qA3TvG2Zw
 
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luvflyin said:
Going over this whole thread again, ronachamp's post #29 reached out and slapped me right upside the head. It's all there. Feeder routes not being authorized to terminate on localizers. FAXAG officially being identified as only a Lat/Long coordinate.

Just flying the radial outbound from VHP waiting for the localizer needle to move and then finding yourself somewhere within the confines of the HILPT and taking it from there doesn't cut it. This Approach should be NOTAM'd down now.
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You should make that assertion on the IFP Gateway.
 
PPC1052 said:
I am not sure that is what he is saying at all. I think his point is only that FAXAG is a fix, not an intersection. The significance being that you cannot identify FAXAG by the cross radial because it's too acute. Instead, it must be identified by the DME distance on the localizer.



I'm not sure that follows, either. There is tremendously more error permitted for IAF procedure entry than for FAF location. Here's a nice little primer: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjJ9dHt5PLMAhVOO1IKHWLtDZYQFggcMAA&url=http://www.terps.com/ifrr/mar97.pdf&usg=AFQjCNG8iajb6l1spQcOUwg5EZGfrno_gQ&sig2=ktmUGvuhB-Cr0qA3TvG2Zw
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Yeah. I guess. But it still doesn't pass the logic check with me. The DME distance is not from the localizer, I-EYE is not a localizer/DME. The DME is from VHP. You would have to fly the (will the real radial please stand and identify yourself) to 14.6 DME. Now you're at FAXAG. Is the localizer needle moving yet? Localizers are pretty narrow. I haven't read the link above yet. I get it that IAF's don't need as tight a tolerance as FAF's and MAP's. I don't think the intent is for someone to arrive at the holding fix and not be within the "width of the localizer" and then begin the hold. I'll read the link when I have more time. I'm not where I can get to simulator but I'm looking forward to flying this approach on one sometime and see what it looks like. Fly it right on the 041 and then the 045 then 037, a reasonable error, +/- 4 degrees, and see what it looks like. I hope someone who is following this and knows the trigonometry will plot it out. How big is FAXAG from one end to the other from 037 off of VHP to 045. At 037 will you be on the localizer yet, and at 045 will you be through it already with the needle pegged off the other side already.
 
luvflyin said:
The DME distance is not from the localizer, I-EYE is not a localizer/DME. The DME is from VHP.
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That's a great point that I overlooked. Since I don't have DME myself, I didn't really look at that aspect closely.
 
This is getting stranger and stranger. The Fix Data Record for FAXAG shows the Fix Make Up Facilities as VHP and I-EYE. The magnetic bearing From VHP to FAXAG is 34.86 and the true bearing is 35.86. 1 degree difference. The magnetic bearing from I-EYE is 30.53 and the true bearing is 25.53. 5 degree difference. Variation in that neighborhood is 4 degrees west. No wonder nobody can draw a chart that makes sense.
 
luvflyin said:
I found the gateway. I'll do it later. Does Jepp have a customer questions site where I can ask where they came up with the 035 radial?
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ChartSupport (ChartSupport@jeppesen.com)
 
I have one friend in the AIS IFP design group. We worked together a lot when we were both on the Performance Based Advisory Committee. He is retiring within a year. He is not happy with the progression of events. It is all about production quotas, and has been for a few years now. The computer-based design system is very good as to obstacle data. But, the two computer systems do not design procedures, a human has to do that in a CAD interface. They can make good designs or they can make lousy designs. Depends upon the individual, their competence, and their motivation. Also, they are highly unionized and some of them are union militants.

Essentially, the entire function is accountable to no one short of a Congressional hearing. And, that is not about to happen.

Their workload is awesome. A procedure submitted today will take at least two years to publication unless it is given priority, such as for a Congressman who puts the heat on for some airport in his district.
 
A friend who knows trigonometry crunched some numbers. It looks like VHP to FAXAG is in fact the 035 radial. Jepp's 035 and the Gov chart's 035R seem to be correct. What's wrong is the Gov's 041 on the feeder route. Now the bearing of the localizer is 031. You fly the VHP 035 to get over to the localizer and join it. You can have +/- 4 degrees error in your VOR and it is ok to use. 035 minus 031 is 4. You could be paralling the localizer. The chart builders are supposedly assuming 4.5 degrees of error. Maybe, just maybe, they intended it be a dead reckoning route of 041 to join the localizer, but I doubt it.
 
PPC1052 said:
...For example, see:
http://www.airnav.com/depart?http://155.178.201.160/d-tpp/1605/06878ILD20.PDF
Here we are told two times that DME is necessary. Wouldn't just once suffice?

Alternatively, see:
http://www.airnav.com/depart?http://155.178.201.160/d-tpp/1605/05733L21.PDF
Here, DME required appears only in the notes box, and could easily be missed. Not that I am saying it's ok to skip the notes box. But the notice of required equipment not as conspicuous there as it is in the plan view. Why not just always list required equipment in the plan view?
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Here are the current versions of those procedures:

JWN ILS OR LOC/DME RWY 20

EYE LOC RWY 21
 
luvflyin said:
Who is @RussR ? Is he in this thread somewhere?
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I am @RussR. (In my mind that sounded like "I am Ironman", in both the Black Sabbath and the Ironman movie versions.)

@AggieMike88 is correct with regards to my employment. However, I tread carefully when it comes to matters where it could be construed that I am representing my employer, as I have no authority to do so (as much as I would like to in these forums).
 
Ok. Understood. Thanks for checking in. If you think maybe the issues about this approach should be looked at, hope you have the time and means to do so.
 
luvflyin said:
Ok. Understood. Thanks for checking in. If you think maybe the issues about this approach should be looked at, hope you have the time and means to do so.
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I passed them along to one of his manger friends a week ago. He responded these issues are not as quickly resolved as they used to be because the "system" is now more cumbersome than it used to be.
 
Follow up question for the ILS or LOC/DME 20 approach at John C Tune (KJWN):

http://www.airnav.com/depart?http://155.178.201.160/d-tpp/1612/06878ILD20.PDF

In math, we have clear rules for the order of operations. But what about for approach plate nomenclature? In this case, which takes precedence, the "or" (meaning "or"), or the "/" (meaning "and") in the approach title? In other words, if you have ILS capabilities, do you need the DME for the final approach course? AIM 5-4-5 is not particularly clear. The plan view indicates that DME or RADAR is required, which kind of suggests that if you have radar and an ILS, you should be ok. But, of course, (as we can see from our above discussion) the statement in the plan view that DME or Radar is required means that it is necessary for procedure entry, and is therefore not entirely inconsistent with needing DME for the final approach course, despite it being largely redundant. And to make things more confusing, the notes box has a friendly "DME required" meaning that DME is required for portions of the approach outside of the final approach segment. So, here we hit the trifecta of redundancy and confusion.
 
"DME or RADAR" required in the plan view means that either DME or ATC RADAR coverage is needed for procedure entry. DME to identify BICOL, or RADAR to get RADAR vectors to final.

ILS or LOC/DME - the "DME" in this case goes with the LOC, meaning that DME is required to fly the LOC final, to identify the FAF (TWITY) and the MAP. You NEVER need a DME to fly an ILS final, as the FAF is identified by glideslope intercept and the MAP is identified by DA when on glideslope.

"DME Required" in the Notes box means that DME is required for the missed approach, to identify BEVEE, because it's just a DME fix with no crossing radial.

So, if you plan to fly the ILS, you have to have DME in order to enter the procedure, do NOT have to have it to fly final (because you never do for an ILS), and DO require it to fly the missed.

Or, if you are in RADAR coverage you effectively do not have to have DME at all, since you will get vectors to final and a radar-vector missed approach anyway.

If you plan on flying the LOC final, you have to have DME, period. Even if you get vectors to final and a vectored missed approach, you need it for the FAF and MAP.

It isn't the best system, but it tries to account for all possibilities. And this example approach follows the rules exactly as they are written.
 
RussR said:
"DME or RADAR" required in the plan view means that either DME or ATC RADAR coverage is needed for procedure entry. DME to identify BICOL, or RADAR to get RADAR vectors to final.

ILS or LOC/DME - the "DME" in this case goes with the LOC, meaning that DME is required to fly the LOC final, to identify the FAF (TWITY) and the MAP. You NEVER need a DME to fly an ILS final, as the FAF is identified by glideslope intercept and the MAP is identified by DA when on glideslope.

"DME Required" in the Notes box means that DME is required for the missed approach, to identify BEVEE, because it's just a DME fix with no crossing radial.

So, if you plan to fly the ILS, you have to have DME in order to enter the procedure, do NOT have to have it to fly final (because you never do for an ILS), and DO require it to fly the missed.

Or, if you are in RADAR coverage you effectively do not have to have DME at all, since you will get vectors to final and a radar-vector missed approach anyway.

If you plan on flying the LOC final, you have to have DME, period. Even if you get vectors to final and a vectored missed approach, you need it for the FAF and MAP.

It isn't the best system, but it tries to account for all possibilities. And this example approach follows the rules exactly as they are written.
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Awesome reply. Thanks for your good advice in terms of how to interpret what the FAA is telling us. I appreciate those, like you, who share their great experience and wisdom with us.

I haven't seen it, but does the AIM, or any other guidance anywhere make clear that you can dispense with DME requirements in the notes box if you are in radar coverage? What do you do if you lose comms on the missed with no DME? I have to go to Nashville in a few months, and would really like to have confidence that I can land at Tune rather than BNA, but I have no DME.
 
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RussR said:
Or, if you are in RADAR coverage you effectively do not have to have DME at all, since you will get vectors to final and a radar-vector missed approach anyway.
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Is it ok to request an approach that requires DME for the missed, advise that you have no DME and ask for alternate missed instructions that require no DME? I looked in the AIM and found nothing. Obviously, ATC can give alternate missed instructions. But I didn't see anything that says it's acceptable try to get ATC to roll me something on the spot due to my lack of equipment. For all I know, the FAA has an alternate missed set forth, but just not published for us pilots to see that the controller could rely on if necessary. But there is no guarantee that it wouldn't also require DME if the primary missed requires DME, and I don't know what the ability of the controller is to make up something on the spot that would work for me and my limited equipment.[/QUOTE]
 
PPC1052 said:
Is it ok to request an approach that requires DME for the missed, advise that you have no DME and ask for alternate missed instructions that require no DME? I looked in the AIM and found nothing. Obviously, ATC can give alternate missed instructions. But I didn't see anything that says it's acceptable try to get ATC to roll me something on the spot due to my lack of equipment. For all I know, the FAA has an alternate missed set forth, but just not published for us pilots to see that the controller could rely on if necessary. But there is no guarantee that it wouldn't also require DME if the primary missed requires DME, and I don't know what the ability of the controller is to make up something on the spot that would work for me and my limited equipment.
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If there is an alternate missed approach there will be an alternate missed approach holding pattern on the chart. If the IAP requires DME the alternate missed approach holding pattern box will not indicate whether DME is required for the alternate missed approach.

If an alternate missed approach is not indicated ATC cannot improvise one, except where they have radar and their facility practices permit missed approach vectors below the MVA.

The short answer to your question: No.
 
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