VOR Minimum Operational Network question

[Dry Creek]

OK, I have a question about the FAA and shutting down VOR stations as they lean more towards GPS navigation. I have downloaded the list from the FAA website and looked at Phase I and Phase II shutdown lists. On Phase II, I see the Glen Rose VORTAC "JEN" (115.0 / Ch 97) as being on that list for decommissioning. When I look on the DFW VFR Sectional, it's no longer there. It is not shown on the San Antonio VFR Sectional anymore either. Yet, it is listed under navigation aids for KSEP and KGDJ in the Chart Supplement (formerly A/FD). The blue information box also appears on the DFW Terminal Area Chart, but no VORTAC symbol or compass rose is shown.

Is there any way to find out the real status of that navaid?

 

[Doug Reid]

ForeFlight shows it as Tacan only...not a VOR.

 

[kaiser]

IFR low chart? It appears to be TACAN only in the latest release.

 

[Dry Creek]

ForeFlight shows it as Tacan only...not a VOR.

Well, I guess that they just shut down the VOR side of it. But why not show the TACAN symbol, and why still have the VOR frequency shown in some products, but not others?

 

[midwestpa24]

Well, I guess that they just shut down the VOR side of it. But why not show the TACAN symbol, and why still have the VOR frequency shown in some products, but not others?

Not much sense mapping a TACAN on civilian charts, not like you could use it.

As for it still showing in the Chart Supplement, probably just an artifact that was overlooked and something that could be reported to get corrected. A VOR may be referenced in a lot of places, not all of which get flagged for correction.

 

[Larry in TN]

Not much sense mapping a TACAN on civilian charts, not like you could use it.

You can use the DME.

 

[RussR]

Well, I guess that they just shut down the VOR side of it. But why not show the TACAN symbol, and why still have the VOR frequency shown in some products, but not others?

Notice how it is listed as a TACAN for the SEP and GDJ listings, and the frequency is listed in parentheses. That means that it isn't really transmitting on that frequency, but that the DME is paired with that frequency. So if you have a DME receiver, you would tune in 115.00, although that's not really the DME frequency - it's the one that's paired with the actual DME frequency, and keeps us from having to tune in two frequencies to receive a normal VOR and DME signal. Since this is a TACAN, it still has DME that is usable and receivable by civilian receivers.

 

[Clip4]

You can use the DME.

You can still use them for RNAV fixes it they are on the chart. Other than that they don’t have much use because the LOC and VOR approaches are being decom. rather quickly.

 

[bflynn]

I'm still wondering what we're going to do when the GPS stops working.

 

[40YearDream]

It seems like the only way to know the status of VOR / DME sites is a NOTAM search - for that particular identifier. You can't trust the charts anymore. You'd think, with 56-day update cycles that the broken VORs (almost certainly never to be repaired) could be taken off at the next revision - but, no - gotta leave 'em on, for some obscure, known-only-to-the-FAA, reason! E.G., check out HIC.

 

[Rgbeard]

I'm still wondering what we're going to do when the GPS stops working.

BTDT.

Earlier this year, leaving El Paso for Goodyear fishing between restricted airspace on an airway, intentional GPS jamming happened.

I already had the VOR queued up carried on without a problem.

 

[Larry in TN]

You can still use them for RNAV fixes it they are on the chart. Other than that they don’t have much use because the LOC and VOR approaches are being decom. rather quickly.

The DME stations are important because DME/DME and DME/DME/IRU are the fall-back systems for the flight management systems on most jet aircraft and transport-category aircraft when GPS-updating is unavailable.

There are still 767, and probably other, aircraft flying around the country without GPS that use DME/DME/IRU to maintain their RNAV position. Ten years ago I flew some of them. Your next Amazon package may have ridden on them.

Earlier this year, leaving El Paso for Goodyear fishing between restricted airspace on an airway, intentional GPS jamming happened.

I had that happen twice in the last month in the same New Mexico airspace. We lose the two GPS position inputs and the FMS falls back to DME/DME/IRU which is accurate enough for enroute and terminal RNAV operations (RNP 2.0 and RNP 1.0). I've only had it happen in cruise in that area though I haven't tried landing at ELP for many years.

We get brief GPS-fail messages when landing at Mexico City. There is apparently a prison, under "left base" on the arrival, which has localized jamming to prevent the inmates from using devices that might be smuggled in. It only lasts a few seconds, though.

In any case, the airplane will give us an alert if our actual navigation performance (ANP) drops below the required navigation performance (RNP) for the airspace, and/or procedure, we are flying. The newer airplanes display the RNP and ANP continuously at the bottom of each navigation display.

 

[NoHeat]

LOC and VOR approaches are being decom. rather quickly.

Localizer approaches being decommissioned? That’s new to me.

If a runway has ILS, why should the corresponding LOC approach be decommissioned?

 

[Clip4]

Localizer approaches being decommissioned? That’s new to me.

If a runway has ILS, why should the corresponding LOC approach be decommissioned?

Both the ILS and the Stand Alone Localizers are being removed. I assumed you knew an ILS also had a localizer and they are being removed too.

There is no need for ILS/LOC at uncontrolled airports with RNAV because mins are usually equal and there is no maintenance and facility monitoring issues. ILS is being maintained at airports part of MON.

 

[Palmpilot]

You can use the DME.

In addition, the location of the TACAN can be included in the GPS database.

 

[Larry in TN]

There is no need for ILS/LOC at uncontrolled airports with RNAV because mins are usually equal

That depends on the aircraft equipment, of course. If the airport has airline service, as many non-towered airports do, they need the ILS as airliners can't fly LPV, only uncompensated LNAV/VNAV minimums. Some do, and more will, have GLS capability but there are not any GLS installations at non-towered US airports at this point.

 

[Palmpilot]

I'm still wondering what we're going to do when the GPS stops working.

Which we are often warned may happen, ON PURPOSE, in some areas.

 

[John Collins]

You can still use them for RNAV fixes it they are on the chart. Other than that they don’t have much use because the LOC and VOR approaches are being decom. rather quickly.

Don't use the stand alone DME identifiers in a flight plan, as the ATC computer will reject them.

 

[John Collins]

I'm still wondering what we're going to do when the GPS stops working.

For the Airlines or any aircraft with an FMS with an RNAV DME-DME or DME-DME-IRU will still be able to use them for enroute and terminal navigation. For GA, we will still have 2/3 of the VOR still in service for enroute navigation and the service volume of the low altitude VOR's will be increased from 40 NM to 70 NM at 5000 feet above the VOR. There will also be MON airports that have conventional ILS or VOR approaches that have no dependency on GPS, DME, ADF, or RADAR located within 100 NM from any point in the NAS. You can find the MON airports in the CONUS chart supplements and they have MON in white text on a green background on the IFR Low Altitude Enroute Charts.

I posted this on the BeechTalk Forum:

At ForeFlight we had our annual winter gathering, this year mostly by video conference. There is a tradition at the company that individuals or groups present what are called "hack presentations" where individuals or teams have an idea and present it to the entire company. Many of these great ideas eventually end up in the product that are first presented in the "hack presentations".

So my idea was to simplify locating a nearby MON airport by developing a map overlay that would highlight the MON airport locations. I don't have the skills to develop such an overlay layer, but fortunately, Josh Berman, a top support manager does. With his brilliant help, he developed an overlay layer that shows a circle (5 NM radius) around each MON airport with a green background to highlight their locations. There are currently 185 airports designated as MON airports. This is available as a user content KML file and I can share it.

Here is the national view showing all the MON airport locations.



Here is the view zoomed in:



Here is the view zoomed in to a specific MON airport:



I put the KML file on a google drive and it can be downloaded as custom content loaded into ForeFlight https://drive.google.com/file/d/1m1A8wHwRBPPxUISfSq-9zvBw4O4m1xmJ/view?usp=sharing

 

[Dry Creek]

You can use the DME.

That was going to be my next question, if the DME side of TACAN was still useful to civilian aircraft - being UHF. I was reading in the AIM today at lunch, and it seemed to infer that it was available to civilians still.

 

[Dry Creek]

Notice how it is listed as a TACAN for the SEP and GDJ listings, and the frequency is listed in parentheses. That means that it isn't really transmitting on that frequency, but that the DME is paired with that frequency. So if you have a DME receiver, you would tune in 115.00, although that's not really the DME frequency - it's the one that's paired with the actual DME frequency, and keeps us from having to tune in two frequencies to receive a normal VOR and DME signal. Since this is a TACAN, it still has DME that is usable and receivable by civilian receivers.

Thank you. Just the kind of information someone new needs to have in their back pocket. That TACAN/DME will be in my flight training AO.

ETA - I still find it odd that the VFR Sectional doesn't show it as just the DME square with the rectangle containing information (115.0). I guess that it is better served for IFR charts and Terminal Area Charts?

 

[TommyG]

Notams in briefings will give all the answers.

 

[Dry Creek]

Notams in briefings will give all the answers.

Especially now that they've removed all gender reference!

But in all seriousness, will they really list a VOR/DME (VORTAC) that has been decommissioned? I could understand if it was down for repair, but this is permanently shut down according to the FAA.

 

[Larry in TN]

That was going to be my next question, if the DME side of TACAN was still useful to civilian aircraft - being UHF.

The azimuth from a TACAN is incompatible with VOR receivers. The DME, in a TACAN is no different from the DME in a VOR/DME. In fact, the DME from a VORTAC is the DME from the TACAN.

The VHF frequency listed for a VOR/DME, VORTAC, or TACAN is only for azimuth (VOR/DME and VORTAC only). The DME channel is different but is permanently paired with that VHF VOR frequency. The DME receiver knows what channel to tune when you select a VHF VOR frequency.
A TACAN, without a co-located VOR, will have the VHF VOR frequency published, though that VHF frequency is not used by the station. It is the paired VHF frequency that matches the TACAN's DME channel.

The DME channels are in the frequency band between 960 and 1,215 MHz which would be classified as UHF.

 

[luvflyin]

For the Airlines or any aircraft with an FMS with an RNAV DME-DME or DME-DME-IRU will still be able to use them for enroute and terminal navigation. For GA, we will still have 2/3 of the VOR still in service for enroute navigation and the service volume of the low altitude VOR's will be increased from 40 NM to 70 NM at 5000 feet above the VOR. There will also be MON airports that have conventional ILS or VOR approaches that have no dependency on GPS, DME, ADF, or RADAR located within 100 NM from any point in the NAS. You can find the MON airports in the CONUS chart supplements and they have MON in white text on a green background on the IFR Low Altitude Enroute Charts.

I posted this on the BeechTalk Forum:



Here is the national view showing all the MON airport locations.

View attachment 103146

Here is the view zoomed in:

View attachment 103145

Here is the view zoomed in to a specific MON airport:

View attachment 103144

I put the KML file on a google drive and it can be downloaded as custom content loaded into ForeFlight https://drive.google.com/file/d/1m1A8wHwRBPPxUISfSq-9zvBw4O4m1xmJ/view?usp=sharing

How do we get that as a selectable Map Layer into our Foreflight?

 

[IK04]

The Temple VORTAC disappeared a few years ago and there is now a square depicting the station, which is only a DME. It also has a FSS repeater on it on 122.6, so they repurposed it to have a voice capability.

I didn't know about JEN, but it makes sense that they would keep the DME for DME-DME navigation. Looking on SkyVector, you can type in JEN and it points to a location on the sectional with nothing there!

 

[Dry Creek]

Looking on SkyVector, you can type in JEN and it points to a location on the sectional with nothing there!

That's what I found so strange. No DME "square" symbol on the overlapping VFR Sectionals, and only the identifier rectangle appears on the TAC. Wouldn't it be more useful if you could visual your distance from the point being measured from?

 

[Rich Holt]

BTDT.

Earlier this year, leaving El Paso for Goodyear fishing between restricted airspace on an airway, intentional GPS jamming happened.

It is amazing how easy a GPS signal is to jam locally with very unsophisticated and inexpensive equipment that anyone can buy on the interwebs. It's not like the FAA is unaware of the problem either. There have been instances of jammers bought on the internet to hide employees' location, gumming up approach paths to major airports. (KEWR) For a relatively inexpensive cost, a person can really mess things for the GPS world.

 

[John Collins]

How do we get that as a selectable Map Layer into our Foreflight?

The way I do it is to download the kml file from the link and attach it to an email addressed to myself. On the iPad, open the email. Tap on the kml attachment. Tap on the send to icon at the top of the KML. Tap on the ForeFlight icon or More if the ForeFlight icon does not show. It will open ForeFlight. Tap on custom content. Tap on Custom Content Map Layers. Tap on OK. Open the Map view and find the new layer MON Airports at the bottom right hand side of the Map layer selector and tap on it to turn it on. There are probably easier ways, but this is the way I have used.

 

[luvflyin]

The way I do it is to download the kml file from the link and attach it to an email addressed to myself. On the iPad, open the email. Tap on the kml attachment. Tap on the send to icon at the top of the KML. Tap on the ForeFlight icon or More if the ForeFlight icon does not show. It will open ForeFlight. Tap on custom content. Tap on Custom Content Map Layers. Tap on OK. Open the Map view and find the new layer MON Airports at the bottom right hand side of the Map layer selector and tap on it to turn it on. There are probably easier ways, but this is the way I have used.

Thanks