Can I shoot a VOR / DME-A approach without a VOR?

Salty

Salty

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https://flightaware.com/resources/airport/ISM/IAP/VOR_DME-A/pdf

So, I got into an argument with someone over this and I have no idea who's right.

I say, the approach plate says "VOR / DME" that means both are required equipment.

He says, you can substitute GPS for DME right?

I say, yeah

He says, then why not for the VOR? It's more accurate than VOR.

I'm so confused.
 
From the FAF in to the MAP, gotta use the ground based radio. (ready to be corrected if I’m wrong)

Yeah, it’ll be more accurate, but no.


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crash7 said:
From the FAF in to the MAP, gotta use the ground based radio. (ready to be corrected if I’m wrong)

Yeah, it’ll be more accurate, but no.


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Click to expand...

Depends on exactly what you mean by "use." You can 'use' RNAV to fly it. And you must also 'use' the VOR to 'monitor' course alignment.

AIM 1-2-3 c. Note 5

5. Use of a suitable RNAV system as a means to navigate
on the final approach segment of an instrument approach
procedure based on a VOR, TACAN or NDB signal, is
allowable. The underlying NAVAID must be operational
and the NAVAID monitored for final segment course
alignment.
 
From the FAF in to the MAP, gotta use the ground based radio. (ready to be corrected if I’m wrong)
Click to expand...
You're wrong. You can substitute GPS for anything other than the lateral guidance on the final approach course. There are only two approaches in the entire country that have DME used for such: VOR or TACAN RWY 15 at KMTN (not sure why this isn't VOR/DME) and the VOR/DME or TACAN RWY 10 at KWAL (NASA facility, unlikely you'll go here).
 
flyingron said:
You're wrong. You can substitute GPS for anything other than the lateral guidance on the final approach course. There are only two approaches in the entire country that have DME used for such: VOR or TACAN RWY 15 at KMTN (not sure why this isn't VOR/DME) and the VOR/DME or TACAN RWY 10 at KWAL (NASA facility, unlikely you'll go here).
Click to expand...

Perhaps I haven’t been drinking enough today. You said I can substitute GPS for anything -OTHER- than the lateral guidance on the final approach course. Wouldn’t that be -the- VOR? (the ground based source). Aren’t we saying the same thing?


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AIM 1-2-3

Please pardon the repetition. I think this is important enough that it needs to be in big, bold, letters. AIM 1-2-3 for every instrument rated pilot and instrument student.
 
luvflyin said:
Depends on exactly what you mean by "use." You can 'use' RNAV to fly it. And you must also 'use' the VOR to 'monitor' course alignment.

AIM 1-2-3 c. Note 5

5. Use of a suitable RNAV system as a means to navigate
on the final approach segment of an instrument approach
procedure based on a VOR, TACAN or NDB signal, is
allowable. The underlying NAVAID must be operational
and the NAVAID monitored for final segment course
alignment.
Click to expand...
Yes, but that still means you need VOR.
 
So I’m finally reading AIM 1-2-3 and isn’t 4 (Pilots May not substitute for the NAVAID...) in direct conflict with 5 (Use of a suitable RNAV system...)??


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flyingron said:
You're wrong. You can substitute GPS for anything other than the lateral guidance on the final approach course. There are only two approaches in the entire country that have DME used for such: VOR or TACAN RWY 15 at KMTN (not sure why this isn't VOR/DME) and the VOR/DME or TACAN RWY 10 at KWAL (NASA facility, unlikely you'll go here).
Click to expand...

The "VOR/DME" nomenclature is gradually going away as procedures are amended, and becoming "VOR" procedures with "DME Required" in the new equipment requirements box.

http://cfiruss.blogspot.com/2018/05/goodbye-dme-hello-equipment.html

Actually, under the current naming convention, these should be "DME or TACAN RWY xx" approaches (since the name of the procedure is supposed to be the type of navigation system used for lateral guidance on final), but that may just be a little too weird.
 
crash7 said:
Perhaps I haven’t been drinking enough today. You said I can substitute GPS for anything -OTHER- than the lateral guidance on the final approach course. Wouldn’t that be -the- VOR? (the ground based source). Aren’t we saying the same thing?
Click to expand...
No it would not. Look at either of the approaches I listed. The VOR is not used for course guidance, you're flying a DME arc all the way to the runway.
 
flyingron said:
No it would not. Look at either of the approaches I listed. The VOR is not used for course guidance, you're flying a DME arc all the way to the runway.
Click to expand...
So, other than 2 goofy examples, he's right. That was more confusing than helpful IMO, but I suppose there is a nuance there.
 
Salty said:
So, other than 2 goofy examples, he's right. That was more confusing than helpful IMO, but I suppose there is a nuance there.
Click to expand...
He wasn't right no matter what he was talking about. He said you couldn't substitute GPS for DME between the FAF and the MAP. That is 100% incorrect on any approach that has DME fixes.
My quoting of the two "goofy examples" was to show the only approaches where he even began to be partially correct. I mentioned them because almost certainly some other pedantic person would have pointed them out.
 
flyingron said:
He wasn't right no matter what he was talking about. He said you couldn't substitute GPS for DME between the FAF and the MAP. That is 100% incorrect on any approach that has DME fixes.
My quoting of the two "goofy examples" was to show the only approaches where he even began to be partially correct. I mentioned them because almost certainly some other pedantic person would have pointed them out.
Click to expand...
No he was referring to using GPS instead of a VOR for lateral guidance which is prohibited according to the AIM
 
Ron, if you guys are talking about my responses, I wasn’t referring to DME at all. The OP asked about using GPS for the VOR tracking. I stated, NO, you need to use a ground based signal for the needle (not DME) inside the FAF.

I have since learned that you -can- use GPS for this segment as long as you are monitoring the VOR anyway.

Then I got confused with the 2 paragraphs that seem to say no you may not, but yes you can if you monitor.

I think we’re caught up now.

And Grum.Man beat me by a few seconds. (Need my daughter’s texting thumbs...)


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crash7 said:
So I’m finally reading AIM 1-2-3 and isn’t 4 (Pilots May not substitute for the NAVAID...) in direct conflict with 5 (Use of a suitable RNAV system...)??
Click to expand...
#4 is a more generic statement while #5 is more specific. #5 still requires that a working VOR receiver is used an monitored.
 
I'm a bit lost.

You can use GPS instead of DME when DME is called for Yes or No?
You must have a VOR when shooting a VOR approach Yes or No?
When shooting a VOR approach, you can monitor the VOR but really use GPS Yes or No?
 
WDD said:
I'm a bit lost.

You can use GPS instead of DME when DME is called for Yes or No?
You must have a VOR when shooting a VOR approach Yes or No?
When shooting a VOR approach, you can monitor the VOR but really use GPS Yes or No?
Click to expand...
Yes
Yes if it’s required for lateral guidance
Sort of yes. You MUST monitor not you may.
 
WDD said:
I'm a bit lost.

You can use GPS instead of DME when DME is called for Yes or No?
You must have a VOR when shooting a VOR approach Yes or No?
When shooting a VOR approach, you can monitor the VOR but really use GPS Yes or No?
Click to expand...
Yes.
Yes.
Yes.
 
WDD said:
I'm a bit lost.

You can use GPS instead of DME when DME is called for Yes or No?
You must have a VOR when shooting a VOR approach Yes or No?
When shooting a VOR approach, you can monitor the VOR but really use GPS Yes or No?
Click to expand...

Yes, UNLESS the final approach course is a DME arc. (This is rare.) GPS substitution is not allowed for lateral guidance on the final approach segment.

Yes, although you can substitute GPS for lateral guidance outside the final segment.

On the third question, no, I think you have to "really" use the VOR for lateral guidance on the final approach segment even if you are also monitoring the GPS. That means that if the two diverge, then you have to keep the CDI on the VOR within limits. (If it's not possible to keep both the VOR and the GPS course deviation within limits, I think I would want to execute a missed approach and try some other approach.)
 
Palmpilot said:
On the third question, no, I think you have to "really" use the VOR for lateral guidance on the final approach segment even if you are also monitoring the GPS.
Click to expand...
Here's what the FAA says about it in the AIM:

Use of a suitable RNAV system as a means to navigate on the final approach segment of an instrument approach procedure based on a VOR, TACAN or NDB signal, is allowable. The underlying NAVAID must be operational and the NAVAID monitored for final segment course alignment.​

In practice, you might not have a second CDI. In a glass PDF system, for example the VOR needle might just be a bearing pointer while you (or your autopilot) flies the entire approach following the GPS. OTOH, what the AIM allows may be overruled by the Limitations applicable to your specific GPS unit.

What to do if they disagree is one of the mysteries of life.
 
Where is it written that you can't use GPS as primary LNAV on a DME Arc on the final approach course on the exactly two approaches that exists on?

crash7 said:
From the FAF in to the MAP, gotta use the ground based radio. (ready to be corrected if I’m wrong)

Yeah, it’ll be more accurate, but no.


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Click to expand...

Incorrect. You must monitor the ground based aid, but may use GPS for primary lateral guidance.

Grum.Man said:
No he was referring to using GPS instead of a VOR for lateral guidance which is prohibited according to the AIM
Click to expand...

That isn't true.

WDD said:
I'm a bit lost.

You can use GPS instead of DME when DME is called for Yes or No?
You must have a VOR when shooting a VOR approach Yes or No?
When shooting a VOR approach, you can monitor the VOR but really use GPS Yes or No?
Click to expand...

Yes
Yes
Yes
 
N1120A said:
You must monitor the ground based aid, but may use GPS for primary lateral guidance.
Click to expand...
That statement is supported for VOR, TACAN, or NDB final-approach segments by the AIM passage that Mark quoted in post #30. Is there a passage somewhere that extends it to DME-arc finals?
 
Palmpilot said:
That statement is supported for VOR, TACAN, or NDB final-approach segments by the AIM passage that Mark quoted in post #30. Is there a passage somewhere that extends it to DME-arc finals?
Click to expand...

GPS is a complete substitute for DME
 
So ... why not just use GPS for everything? Can the plane be IFR legal with a GTN 650 but no ADF, VOR, or ILS?

Digging into studying for the written - lot of VOR, airways, radio navigation, ADF compass marker, ILS, etc. I would have thought that people flying IFR today would be on GPS????
 
WDD said:
So ... why not just use GPS for everything? Can the plane be IFR legal with a GTN 650 but no ADF, VOR, or ILS?
Click to expand...

The way I understand it, yes. IF, it’s WAAS (“sole means of navigation”).

Based on other replies, you wouldn’t be able to shoot any VOR/LOC/ILS approaches because you wouldn’t be able to ‘monitor’ them.


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crash7 said:
The way I understand it, yes. IF, it’s WAAS (“sole means of navigation”).

Based on other replies, you wouldn’t be able to shoot any VOR/LOC/ILS approaches because you wouldn’t be able to ‘monitor’ them.


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Click to expand...
"Monitoring" is enough for VOR but not for LOC/ILS.
 
A GPS does NOT replace the glideslope on an ILS.
 
midlifeflyer said:
"Monitoring" is enough for VOR but not for LOC/ILS.
Click to expand...

So, for LOC/ILS, you *would* have to actually USE the NAV radio for the final approach segment?


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