Why is an ADF required?

TMetzinger

TMetzinger

Final Approach
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Tim
It may be the drink I had with dinner, but I can't figure out why an ADF is required for this procedure, Cumberland's LOC/DME 23.

http://www.naco.faa.gov/d-tpp/0805/05263LD23.PDF

the CBE NDB isn't labelled as an IAF, and all the fixes that ARE part of the procedure have localizer or VOR radials to define them.

I'm guessing that the CBE NDB is a feeder fix to get you to the IAF, and it's the ONLY way to get there, though it looks to me like you could head to GRV and head outbound on the 084 Radial to HOLOE.

Regardless, to fly this tomorrow in simulated conditions, I believe I'm good to go with a WAAS G1000 unit, using the GPS to substitute for DME and NDB. I'll see what transitions pop up when I load the procedure.

Anyway, I'm sure I'm missing something, and would appreciate some enlightenment.
 
The only thing I see that could cause the requirement is the MSA circle is based on CBE and without the ability to identify CBE you would not know where you are in relation to it.
 
TMetzinger said:
It may be the drink I had with dinner, but I can't figure out why an ADF is required for this procedure, Cumberland's LOC/DME 23.

http://www.naco.faa.gov/d-tpp/0805/05263LD23.PDF

the CBE NDB isn't labelled as an IAF, and all the fixes that ARE part of the procedure have localizer or VOR radials to define them.

I'm guessing that the CBE NDB is a feeder fix to get you to the IAF, and it's the ONLY way to get there, though it looks to me like you could head to GRV and head outbound on the 084 Radial to HOLOE.

Regardless, to fly this tomorrow in simulated conditions, I believe I'm good to go with a WAAS G1000 unit, using the GPS to substitute for DME and NDB. I'll see what transitions pop up when I load the procedure.

Anyway, I'm sure I'm missing something, and would appreciate some enlightenment.
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As far as I can see, the only way out of the missed approach hold back to the approach is via the NDB. Chances are that's the reason.
 
lancefisher said:
As far as I can see, the only way out of the missed approach hold back to the approach is via the NDB. Chances are that's the reason.
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WOW that is subtle. I did not see that until you pointed it out. What a nasty return from the hold. That is one of those you hope for vectors to final type of procedures!
 
Actually, the only ways into the approach are via the CBE NDB. You can't navigate to HOLOE any way but with a GPS (which they can't require) without going through CBE NDB, and the only way to get to CBE NDB is with an ADF (or a GPS, again, something they can't required for an approach that doesn't say "GPS" in the title). Hence, "ADF REQUIRED."

BTW, this is a good airport for an IR training discussion, both for the approaches and for the ODP. Just tell the trainee to plan an IFR flight to Dayton OH. They'll plan direct GRV and then airways. Then ask what they'll do on departure. Most will just say "climb to 400 and turn direct GRV" without noticing the big T in the notes block. Then tell them they just died -- and show them the sectional with the 3000-foot ridge between KCBE and GRV, and then show them the ODP. It's an eye-opener.

BTW, you don't need an ADF for the missed. Just fly heading 184, intercept the GRV 130 radial, and fly it out to KEYER using either the GRV 18.1 DME or a crossbearing off ESL to let you know when you're there. The fact that you need an ADF to get back to the approach from the MA hold is not a consideration.
 
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I don't see a bold line from the NDB making it part of the approach. And I don't see a bold line from Grantsville to the NDB making it part of the approach. And the IAF isn't the NDB. So I still don't get why. Especially since the radial from Grantsville to the NDB also intercepts the localizer.
 
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Ron Levy said:
BTW, this is a good airport for an IR training discussion, both for the approaches and for the ODP. Just tell the trainee to plan an IFR flight to Dayton OH. They'll plan direct GRV and then airways. Then ask what they'll do on departure. Most will just say "climb to 400 and turn direct GRV" without noticing the big T in the notes block. Then tell them they just died -- and show them the sectional with the 3000-foot ridge between KCBE and GRV, and then show them the ODP. It's an eye-opener.
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Absolutely... I did some Hood approaches there and on the second my CFII said "go ahead and look..."

Wow..the ridge seems awfully close....
 
More than meets the eye here. The three feeders leading to the CBE NDB (GRV to CBE, KEYER to CBE, and FLINT to CBE) all have courses that are completely or significantly outside of the I-CBE service volume. As we all remember (hopefully!) off course indications outside of the service volume are not reliable and false courses can and do occur. The idea here is to be on the appropriate bearing or radial with the CBE NDB ahead of you until within the I-CBE service volume where off course indications are positive and the procedure can be flown as charted. The CBE NDB is within the I-CBE LOC service volume and provides positive course guidance to the pilot.
 
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So why can't you just fly the 084 off GRV to the IAF? And "because it's not charted that way" is not an answer. You're using the radial to ID the IAF anyway, so it's obviously usable.
 
EdFred said:
So why can't you just fly the 084 off GRV to the IAF? And "because it's not charted that way" is not an answer. You're using the radial to ID the IAF anyway, so it's obviously usable.
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Ed, it's basically the same answer as what I posted just previously. To use the 084 radial as a feeder, the localizer would have to provide you with reliable off course indications throughout the whole length of the radial from the VOR to the centerline of the LOC and beyond. It just don't work in this case nor in very many just like this. It's fine as a crossing radial to ID HOLOE once you are on the LOC heading inbound or outbound but it doesn't provide you that positive course guidance you need.
 
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Well I fired up the G1000 sim this morning, and found that CBE is part of the transitions from GRV, FLINT, and KEYER. So, as otherwise noted, you need an ADF or GPS for this approach.

What I wish is that in cases like this the charts would say "ADF or GPS required". The rules governing substitution of GPS for NDB and DME on approaches can be subtle, and it's a bit much to ask a pilot to look at a chart that says "ADF REQUIRED" and decide that "no, it's not".

At least the NDB approach to CBE isn't published anymore - that approach was a killer.
 
TMetzinger said:
Well I fired up the G1000 sim this morning, and found that CBE is part of the transitions from GRV, FLINT, and KEYER. So, as otherwise noted, you need an ADF or GPS for this approach.

What I wish is that in cases like this the charts would say "ADF or GPS required". The rules governing substitution of GPS for NDB and DME on approaches can be subtle, and it's a bit much to ask a pilot to look at a chart that says "ADF REQUIRED" and decide that "no, it's not".

At least the NDB approach to CBE isn't published anymore - that approach was a killer.
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When's the last time that NDB was flight tested? As I mentioned earlier, I've found instances in which an NDB hasn't been NOTAMed OTS, even though many of the pilots in the area have determined it is OTS. (Witness DKB).
 
EdFred said:
I don't see a bold line from the NDB making it part of the approach. And I don't see a bold line from Grantsville to the NDB making it part of the approach. And the IAF isn't the NDB. So I still don't get why. Especially since the radial from Grantsville to the NDB also intercepts the localizer.
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There is just no other way to legally get to the IAF. The radial from GRV to the IAF is not a feeder route, while the line from CBE to the IAF is. The fact that a radial is depicted doesn't make it a "published route." Unless there's an altitude and distance associated, it's not a "published route," and when flying IFR other than on a radar vector or ATC-approved GPS or navaid-direct routing, you must stay on published routes.
 
gprellwitz said:
When's the last time that NDB was flight tested? As I mentioned earlier, I've found instances in which an NDB hasn't been NOTAMed OTS, even though many of the pilots in the area have determined it is OTS. (Witness DKB ).
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Approaches are flight-checked routinely. While I'm not sure of the required interval, I believe it's a matter of months, not years.
 
Fast n' Furious said:
To use the 084 radial as a feeder, the localizer would have to provide you with reliable off course indications throughout the whole length of the radial from the VOR to the centerline of the LOC and beyond.
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On the enroute chart, is this one of those 'atc function, symbols which means the LOC is used to id an intersection? Why the 5000'?
 
Ron Levy said:
when flying IFR other than on a radar vector or ATC-approved GPS or navaid-direct routing, you must stay on published routes.
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Not so, unles there's a change I don't know about.

I can file and fly any radial I choose. There are many airports not on an airway or a feeder route.
 
scottd said:
Just fly heading 184...try that when there's a 50 knot wind out of the west at 5,000 feet. Talk about drifting off course! Been there done that one...and got the T-shirt.
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But that is the missed app instructions: "..via heading 184." ...although I would track 184 from CBE, but it's not a requirement.
 
nosehair said:
I can file and fly any radial I choose.
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Not under IFR without ATC's specific approval, and that doesn't play for SIAP's -- ATC is not authorized to issue variations on SIAP's other than those specifically approved by the TERPS folks, like alternate missed approaches.
 
nosehair said:
On the enroute chart, is this one of those 'atc function, symbols which means the LOC is used to id an intersection? Why the 5000'?
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This is one of those times I wish I had enroutes hanging around. One of three things; either that's what ATC wanted when the fix was requested OR that's the lowest altitude that the LOC worked reliably at the fix distance OR that's the lowest altitude that the frequency management folks would approve.
 
OK, looking at the enroute chart and the apprach chart, I see a transition from the grv vor to CBE (093/5000/14.1) and another transition from Flint Intersection to CBE (272/5000/9.2), and one from Keyer, so an ADF is required because these are the transitions off the surrounding airways to the NDB, then 055/4500/4.3 to the IAF.
 
nosehair said:
OK, looking at the enroute chart and the apprach chart, I see a transition from the grv vor to CBE (093/5000/14.1) and another transition from Flint Intersection to CBE (272/5000/9.2), and one from Keyer, so an ADF is required because these are the transitions off the surrounding airways to the NDB, then 055/4500/4.3 to the IAF.
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Bingo! All roads lead to the NDB.
 
Ron Levy said:
There is just no other way to legally get to the IAF. The radial from GRV to the IAF is not a feeder route, while the line from CBE to the IAF is. The fact that a radial is depicted doesn't make it a "published route." Unless there's an altitude and distance associated, it's not a "published route," and when flying IFR other than on a radar vector or ATC-approved GPS or navaid-direct routing, you must stay on published routes.
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Ron, where does it say that you have to fly to the IAF of an approach on a "legal" published route. I know that you can't make up your own route past the IAF but I've always been under the impression that getting to the IAF requires adherence to the same rules as apply to the enroute portion of a flight baring a note on the chart to the contrary (e.g. "procedure NA when arriving via...) and AFaIK that would allow flying a radial from a nearby VOR (within the SSV) to the IAF. I think that published transitions are shown to provide a path which allows a lower altitude during that leg than might otherwise be available and when a usable route lies outside a navaid's SSV.
 
lancefisher said:
Ron, where does it say that you have to fly to the IAF of an approach on a "legal" published route.
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How else can you get there? You're talking point-to-point nav, and that requires GPS or RNAV (which aren't listed as required for this approach) and since the IAF on this one is defined off a LOC, you can't even use a VOR/DME RNAV to get you there. If you're talking about entering via the GRV radial which defines the IAF, you don't have a legal altitude to fly. Maybe there's a problem with the 084 radial partway out, maybe there's an obstacle clearance issue, who knows? But it's not authorized without outside assistance, and that's the way it is.

Could ATC provide radar service and an MIA/MVA to get you to HOLOE via some other route? Possibly, although I have no idea how good Cleveland Center's radar coverage is out there at 5000 and below (not good, I'd think, given the local terrain). But the approach has to be published so you can fly it with only the equipment and assistance printed on the chart, and for whatever reason, they're not happy with you flying out the GRV 084 to HOLOE on your own.
 
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Ron Levy said:
In an old FAA Chief Counsel interpretation, circa 1984 or so. Absent radar service to get you on at a published altitude (like vectors to final), you're only allowed to enter a SIAP at an IAF.
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and the fun starts when you want to fly a DME arc in a non radar environment. The IAF is usually charted way back at the beginning, but can you intercept the arc anywhere along it and proceed inbound?
 
tonycondon said:
and the fun starts when you want to fly a DME arc in a non radar environment. The IAF is usually charted way back at the beginning, but can you intercept the arc anywhere along it and proceed inbound?
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Nope, and this one was specifically answered by the FAA Chief Counsel a long time ago. In a non-radar environment, you must commence from a published IAF, period.
 
Ron Levy said:
How else can you get there? You're talking point-to-point nav, and that requires GPS or RNAV (which aren't listed as required for this approach) and since the IAF on this one is defined off a LOC, you can't even use a VOR/DME RNAV to get you there. If you're talking about entering via the GRV radial which defines the IAF, you don't have a legal altitude to fly. Maybe there's a problem with the 084 radial partway out, maybe there's an obstacle clearance issue, who knows? But it's not authorized without outside assistance, and that's the way it is.
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Why don't you have a "legal altitude" coming from GRV to the IAF? You could certainly have a legal altitude flying along the same radial if you were headed somewhere else. And point to point nav isn't required to reach an intersection formed by two radials, it seems to me that the same should apply to a radial and a LOC.


Could ATC provide radar service and an MIA/MVA to get you to HOLOE via some other route? Possibly, but the approach has to be published so you can fly it with only the equipment and assistance printed on the chart, and for whatever reason, they're not happy with you flying out the GRV 084 to HOLOE on your own.
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I still say that nothing on the chart clearly indicates that "they're not happy" with a pilot flying a transition from GRV to HOLOE. It might be that you can't count on receiving the VOR on that route below the MIA and therefore would have to descend elsewhere on the approach but that in itself shouldn't preclude the use of this route. ESL, HGR, MRB are also all within 40 nm of HOLOE. Assuming they have 80 nm diameter SSVs I'd think you could fly to HOLOE from any of them as well although it might be a bit tricky to do without three separate nav receivers.
 
lancefisher said:
Why don't you have a "legal altitude" coming from GRV to the IAF?
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Why? I can only speculate, and I did in my last post.
You could certainly have a legal altitude flying along the same radial if you were headed somewhere else.
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Not shown on this SIAP chart. And the GRV 084 isn't an airway on the slightly outdated L-chart I have at home. It simply is not a published route/segment. As I said, one might be able to get an altitude to fly if one were in radar contact with Cleveland Center, but it's not a "published" altitude, and without that, you can't fly it without outside help, which would mean "RADAR REQUIRED," which it doesn't say on this chart.
And point to point nav isn't required to reach an intersection formed by two radials, it seems to me that the same should apply to a radial and a LOC.
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If you happen to be coming from GRV (or can get established on the GRV 084 radial), perhaps, but it's not a published route.
I still say that nothing on the chart clearly indicates that "they're not happy" with a pilot flying a transition from GRV to HOLOE.
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I see nothing that says they are -- no published routing from GRV to HOLOE other than via CBE. And if it isn't published, you can't fly it on your own, which is what SIAP's are supposed to be about.
 
I agree that the GRV084 radial isn't plotted as a feeder route to HOLOE, but I am curious WHY not... the GRV > CBE > HOLOE is a more complicated route (3 nav aids: VOR, ADF, LOC; 3 legs) than just plotting the GRV084 > HOLOE transition.

There must be a REASON why the IAP designers left off that transition as a possible route to the IAF. Until I know what that reason is, I'd stick to the plotted arrival routes, especially when non-radar.
 
Gents. Go back and read my post from 5/22/08 at 11:21 PM. It's not a feeder because it can't be a feeder and it has nothing to do with the VOR. It has everything to do with the inability of the LOC to show you off course for the huge segment from the VOR to the LOC service volume while the LOC is in essentially a half power or RF mode. That's the story. Has nothing to do with what the designers want, it's all about what the equipment on the ground can do.
 
Fast n' Furious said:
Gents. Go back and read my post from 5/22/08 at 11:21 PM. It's not a feeder because it can't be a feeder and it has nothing to do with the VOR. It has everything to do with the inability of the LOC to show you off course for the huge segment from the VOR to the LOC service volume while the LOC is in essentially a half power or RF mode. That's the story. Has nothing to do with what the designers want, it's all about what the equipment on the ground can do.
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Um, true, but CBE IS part of every transition to the IAF. So unless you can go GPS direct to HOLOE or get vectors, you need the ADF to go to CBE.
 
No consideration is given to what you can substitute this or that for. You need the ADF for the reasons mentioned in my post on 5/22/08 on 11:09. It is all about providing a pilot with positive course guidance until inside of the service volume of the primary NAVAID which in this case is the LOC.
 
The underlying problem here, is it says "ADF required". It does not say, ADF or GPS required.

So whatever the reason, ADF is required. Too many guys want to risk their frikking necks thinking, "I don't believe it really says that".

It's just like the new change on 8500-8 form GG as to "which resulted in attendance at an educational program".

The airman, who is NOT Flightcheck 99 could not possible be expected to understand why it says, "ADF required". It is SIMPLY, REQUIRED. Wishing it otherwise does NOT make it so.

Geesh.
 
Bruce, you're not saying that you can't substitute IFR GPS for the ADF on this approach, are you? If you are, please explain why.

And in response to your:
"Wishing it otherwise does NOT make it so.

Geesh."

I haven't gotten the impression that people were wishing it wasn't so. I brought the topic up because unlike an NDB approach without a GPS overlay (where a GPS cannot substitute for the ADF), this one appeared to allow for GPS substitution, and I wanted to be sure I hadn't missed some reason why an actual ADF would be required. Thanks to the other folks on the list (who weren't as grumpy as you seem to be today), we had a useful discussion about why an NDB might be a required part of an approach procedure even though it isn't used from the IAF to the MAP or to the missed approach holding pattern.

Hope you feel better,
 
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bbchien said:
The underlying problem here, is it says "ADF required". It does not say, ADF or GPS required.
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True, but AIM Section 1-2-3a says that you can sub a GPS for an ADF in this situation.

That said, if you really want to know why a feeder route to HOLOE via the GRV 084 radial, you'd have to ask the procedure designer down in his/her cubical in the basement at 800 Independence Ave why s/he chose not to do so. Just remember that as published, the only ways into this approach are through CBE NDB, and that means "ADF REQUIRED" (unless you have an approved substitute for an ADF, like an IFR GPS).
 
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Ron Levy said:
That said, if you really want to know why a feeder route to HOLOE via the GRV 084 radial, you'd have to ask the procedure designer down in his/her cubical in the basement at 800 Independence Ave why s/he chose not to do so.
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Do you people all have John on "ignore" or something??? :dunno: We have our very own procedure designer right here who told us why, TWICE, and we're still arguing over it. :dunno:
 
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