Help with basic DME arc question

[Hawk570]

I was practicing DME arcs in the C182 and came across this one at Bowerman in Washington State.

Please refer to the following approach plate...

https://skyvector.com/files/tpp/1707/pdf/00889ILD24.PDF

I must be missing something really basic. I want to enter the arc at ZEDAT. The VOR for the arc is HOQUAM (HQM). According to the chart, there is no DME at HQM to base the arc upon and is shown on the sectional without a square around it. Is it on a different frequency and if so where is it published?

Once on the localizer the plate says to use the localizer's DME so all is good there. What am I missing here?

Thanks

Mark

[Alfredson007]

I am not sure but i think the VORTAC should give the DME...? Maybe it's a bug or your Cessna's transponder do not understand mil-spec dme or something =)

[LZ-WIL]

Hi,

Hmmm, that is interesting I am perplexed too. For the ILS it uses the localizer DME at 108.7, but still how to measure 21 miles from HQM VOR without DME there?
I hope our more experienced friends here and real world aviators will help us understanding this approach plate.

Cheerz,
Will

[Hawk570]

Hi,

Hmmm, that is interesting I am perplexed too. For the ILS it uses the localizer DME at 108.7, but still how to measure 21 miles from HQM VOR without DME there?
I hope our more experienced friends here and real world aviators will help us understanding this approach plate.

Cheerz,
Will

Yes, I got all setup for this flight, took off from KAST and no DME signal. Hmmmmm. I assume that SkyVector's charts are correct. <baffled>

[TreeTops]

Which frequency are you tuned for? 117.7 or 108.7?
Top left corner of the chart States the DME/LOC frequency as 108.7.
The note at the bottom of chart stating to use the DME frequency on approach is so you are not using 117.7 as a localiser guide.
Use 117.7 to arrive in the area then switch to 108.7 to perform the DME arc and LOC approach.
If you fly an aircraft with 2 independent Nav radios and indicators you should be able to test this.
Somewhere further out than 21nm the indications should have activity on the 108.7 frequency and this is when you would switch the active Nav radio to 108.7.
I haven't tested this so it will be interesting what you find.

[Hawk570]

Treetops,
Thanks. however the VOR that the arc is based on is miles from the localizer which is on field. The plate clearly shows the arc based on vor HQM. You wouldnt tune 108.7 until you are ready to exit the arc and establish on the localizer

[AKar]

In this case, the HQM is a VORTAC, or a civilian VOR co-located with TACAN. Essentially, you can receive the VOR, and the DME portion of the TACAN, which is in this context equivalent to the regular DME. Effectively, a VORTAC is a VOR/DME for civilian navigation in FSX context.

-Esa

[Hawk570]

In this case, the HQM is a VORTAC, or a civilian VOR co-located with TACAN. Essentially, you can receive the VOR, and the DME portion of the TACAN, which is in this context equivalent to the regular DME. Effectively, a VORTAC is a VOR/DME for civilian navigation in FSX context.

-Esa

So, I would need a TACAN receiver set to ch 124?

[AKar]

In this case, the HQM is a VORTAC, or a civilian VOR co-located with TACAN. Essentially, you can receive the VOR, and the DME portion of the TACAN, which is in this context equivalent to the regular DME. Effectively, a VORTAC is a VOR/DME for civilian navigation in FSX context.

-Esa

So, I would need a TACAN receiver set to ch 124?

No. Or y...no.

Just forget about the channels, if they confuse you.

Understand this:
- A VORTAC beacon has both the civilian VOR and the military TACAN co-located;
- Both share the DME part to most practical extends;
- While they differ in their "VOR-representation", as it is a VORTAC, a VOR lateral guidance is available. VORTAC would be for military receivers.

In your case, VORTAC is an equivalent to a VOR/DME to the extend we'd care in this simulator!

Summarum: VORTAC in general has a civilian VOR, and the military TACAN co-located, and the military TACAN typically has a DME that is similar to civilian, and co-channeled with VOR-coupled DME frequencies. So, you pick both the VOR portion, and the TACANs DME portion. If it was a sole TACAN, you could still use its DME portion, but there would not be a detectable VOR-like signal, unless you happened to have a TACAN receiver.

-Esa

[Hawk570]

In this case, the HQM is a VORTAC, or a civilian VOR co-located with TACAN. Essentially, you can receive the VOR, and the DME portion of the TACAN, which is in this context equivalent to the regular DME. Effectively, a VORTAC is a VOR/DME for civilian navigation in FSX context.

-Esa

So, I would need a TACAN receiver set to ch 124?

No. Or y...no.

Just forget about the channels, if they confuse you.

Understand this:
- A VORTAC beacon has both the civilian VOR and the military TACAN co-located;
- Both share the DME part to most practical extends;
- While they differ in their "VOR-representation", as it is a VORTAC, a VOR lateral guidance is available. VORTAC would be for military receivers.

In your case, VORTAC is an equivalent to a VOR/DME to the extend we'd care in this simulator!

Summarum: VORTAC in general has a civilian VOR, and the military TACAN co-located, and the military TACAN typically has a DME that is similar to civilian, and co-channeled with VOR-coupled DME frequencies. So, you pick both the VOR portion, and the TACANs DME portion. If it was a sole TACAN, you could still use its DME portion, but there would not be a detectable VOR-like signal, unless you happened to have a TACAN receiver.

-Esa

Thank you for taking the time to explain that. We learn something new everyday. I knew most of that but my real confusion was because I couldnt receive the DME for some reason. Ill go back and try again. Im using A2A C182 and Orbx PNW.

Thank you for clearing that up.

Mark

[Hawk570]

Ok, I tried it in the Comanche and it picked it right up. I must have screwed the pooch with the radios. Thanks again!

[TreeTops]

Just checked it myself and I need to correct what I wrote previously.
117.70 is used for the DME arc and then switch to 108.70 for the localizer.
Both frequencies carry DME information.

[pilottj]

DME arcs are fun practice. Try out KMTN Martin State's famous VOR 15 approach. For extra challenge use an aircraft with only CDIs, turn off the GPS, and fly it the old way. Use the missed approach as the departure procedure, then fly the procedure.



Cheers
TJ

[Hawk570]

DME arcs are fun practice. Try out KMTN Martin State's famous VOR 15 approach. For extra challenge use an aircraft with only CDIs, turn off the GPS, and fly it the old way. Use the missed approach as the departure procedure, then fly the procedure.



Cheers
TJ

Thanks TJ. I generally practice them with a single VOR/DME and no GPS usually with A2A 182, Comanche or PMDG NGX. These are fun. I use the fly ten/twist ten and/or groundspeed=0 methods.