Bye bye VOR Airway Nav

Tom-D

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Tom-D
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The other day, I was looking into an obscure issue related to instrument approach procedures, and my research led me to Government / Industry Aeronautical Charting Forum.

The minutes of the April 27-28, 2011 meeting include an interesting item about the future of VOR-based navigation, which I reproduce below:

DRAFT
Rev 4 April 7, 2011
AERONAUTICAL CHARTING FORUM
Charting Group
Instrument Procedures Group
ACF Meeting 11-01
RECOMMENDATION DOCUMENT
FAA CONTROL __11-01-241______

SUBJECT: Discontinuation of VOR Service and Associated Airways

BACKGROUND/DISCUSSION: To meet needs for performance based navigation (PBN) and required navigation performance (RNP) for capacity, efficiency and safety area navigation (RNAV) is being implemented in the airspace of the United States. The FAA will transition to PBN based on area navigation RNAV everywhere and RNP where beneficial, enabled by Global Positioning System (GPS) as the primary means and DME/DME/IRU as an initial Alternate to ensure safety and continuous operations in the high altitudes and major terminal areas if GPS becomes unavailable.

VOR service can not meet the needs for RNAV and PBN in most situations. Therefore, the FAA is beginning to discontinue VOR service from facilities in CONUS and intends to have a minimum network in place in 2020. This discontinuation of VOR service will affect approximately half of all VORs in CONUS. Remaining facilities will be used for terminal and enroute functions and reviewed for discontinuation at a later date to move to a totally RNAV airspace system.

Existing Victor Airways and Jet Routes will be replaced by T routes (low altitude) and Q routes (high altitude) and terminal and approach procedures will be RNAV based.

RECOMMENDATION:

1. The proposed rulemaking action with associated collection and response to comments is sufficient for this discontinuation of service. No formal rulemaking action will be needed for the discontinuation of service from each VOR facility, each airway or airway segment or for each procedure. These will be handled through the informal process used for Part 71 and Part 73 or the non-rulemaking circularization for technical changes in accordance with JO 7400.2H.

2. The following questions in aeronautical charting and flight procedures should be answered:

a. Should VORs be discontinued to remove whole Jet routes /Victor airways or should individual facilities be removed that will allow the airways to continue as is, possibly with minor rerouting? If airways are to be kept as long as possible what would the impact be on airspace design/redesign and charting?

b. Should Q and T routes be designed and implemented to replace Jet routes/ Victor airways before the VORs describing those routes are discontinued? Should the Q or T route replacing the Jet or Victor be overlayed on those airways/routes and as the VOR service is discontinued the route turns into a Q or T route?

c. When VORs are discontinued such that Victor airways or Jet routes can not be maintained should aircraft not capable of RNAV operation be cleared directly from one VOR to another?

d. For discontinuing VORs supporting terminal procedures (SIDs, STARs, SIAPs) what should the priority order be? Should service be discontinued such that arrivals, departures and approaches are maintained for each direction though not on all runways, then one direction removed and eventually all removed leaving only RNAV based procedures?
As you can see, at this point there are no specifics about which VORs will be turned off and on what schedule. That information is supposed to be in the Federal Radionavigation Plan, updated every two years (the 2010 edition is here [PDF]). The FAA is clearly thinking about the issues involved and soliciting comments from the aviation community, but the agency still hasn’t released a detailed list of navaids that it plans to shut down.

end Quote

as the airlines go so does the FAA and the Nav system.

thinking about buying used NAV equipment? best think that over, it will be pretty cheap soon.
 
And note that they have no backup to the GPS for the GA pilot in mind:
DME/DME/IRU as an initial Alternate to ensure safety and continuous operations in the high altitudes and major terminal areas if GPS becomes unavailable.
 
It is a draft of a recommendation to gather comments on stoping something 9 years from now. I think it is a little premature to start saying our bub-byes.

That VORs will someday be a thing of the past is inevitable. Will it be in the next couple of years? Nope, that is not the case at all.
 
This is just a way to bypass the whole argument over GA user fees for ATC services.

This would be fine IF they let me use portable GPS for enroute navigation.
 
Memo to self: Get ADF fixed.

That would be more funny to me if the Commercial test prep study materials I am using weren't so FULL of ADF questions. But with the revamp of the written tests, I'm not sure exactly what to study now . . .
 
Memo to self: Get ADF fixed.

You mean you don't have Loran? :dunno:

Knowing what I know about the fragility of GPS, this will put GA in a world of hurt unless someone comes out with an anti-jam system or a back-up system fairly soon.
 
Time for a privately funded LORAN style chain to fire up? Nobody wants HF spectrum anyway...
 
Time for a privately funded LORAN style chain to fire up? Nobody wants HF spectrum anyway...
Besides the ARRL, Maritime HF broadband, broadcasters and a few others. The maritime services are the ones that seem to really be going after some tech proposals. That has consistently surprised me as it would seem that satellite is a great service for them. But there are always some companies going after some allocations for data network in HF using OFDM. There are some guys trying to do it again for the next WRC.
 
Besides the ARRL, Maritime HF broadband, broadcasters and a few others.

ARRL's just being greedy. We have enough. ;)

Broadcasters are already there but still use AM? Sheesh. Try some SSB kids. The radios today can tune that stuff for the user so it sounds right.

HF broadband?! Pardon me while I pick myself up off the floor from falling out of the chair laughing. That's like saying someone wants low-latency geosynchronous satellite comms. ;)

Shutting down LORAN was a mistake of epic proportions. It was "expensive to operate" not because the system was expensive, but because of decades of bureaucracy. Sigh.
 
HF broadband?! Pardon me while I pick myself up off the floor from falling out of the chair laughing. That's like saying someone wants low-latency geosynchronous satellite comms. ;)
I think you are missing the propagation advantages of HF. Yeah the bandwidth really suck, but hard to do any sort of NLOS for the distances that they say they need above 30MHz. So HF starts to look better.

Attached is an older proposal that outlines some of their needs. Kind of an interesting approach. I think their prime driver is that it is cheaper than satellite.
 

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  • R0A0E0000280001MSWE-1.doc
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This is just a way to bypass the whole argument over GA user fees for ATC services.

This would be fine IF they let me use portable GPS for enroute navigation.

A handheld GPS can be used VFR. It can even be used under IFR (as a supplement), the aircraft just has to have the equipment appropriate to the clearance/route.
 
It can even be used under IFR (as a supplement), the aircraft just has to have the equipment appropriate to the clearance/route.

Yes, but if you take away the VORs.....what'ya gonna use other than the GPS to navigate the route?

That's what I'm referring to. If they get rid of VORs, I'm going to guess that at least 75% of the current GA fleet will be incapable of IFR flight.
 
Yes, but if you take away the VORs.....what'ya gonna use other than the GPS to navigate the route?

That's what I'm referring to. If they get rid of VORs, I'm going to guess that at least 75% of the current GA fleet will be incapable of IFR flight.
You mean we don't have DME/DME/IRU (Inertial Reference Unit) in the majority of GA aircraft? :mad2:
 
They mentioned DME/DME/IRU in the draft linked in the OP, too.

1) how many GA aircraft have dual DME, which I presume is required for this, much less IRU? Most of the planes I've flown are using GPS to substitute for DME. (Admittedly a small sample)

2) A DME requires a navigation source to measure from, right? If they decommission the VORs, I presume they'll be decommissioning the TACAN, too, so what is the DME measuring to? Don't there need to be two TACANs within range to use DME/DME? (And I'm being a little loose with terminology here. I think that I'm using TACAN to refer to both the true TACAN and the DME transponder that is often co-located with a VOR. Feel free to correct me if I misunderstand.)
 
On my recent long cross country to Arizona (long for me) I used my Aera 510 GPS and both my VORs and my DME. It was kind of a security blanket for me, having several ways of checking my progress. I flew on VOR airways the whole trip.

I won't be around long enough to see the demise of the VORs, but I think for folks like myself, they will be sorely missed.

John
 
They mentioned DME/DME/IRU in the draft linked in the OP, too.

1) how many GA aircraft have dual DME, which I presume is required for this, much less IRU? Most of the planes I've flown are using GPS to substitute for DME. (Admittedly a small sample)

2) A DME requires a navigation source to measure from, right? If they decommission the VORs, I presume they'll be decommissioning the TACAN, too, so what is the DME measuring to? Don't there need to be two TACANs within range to use DME/DME? (And I'm being a little loose with terminology here. I think that I'm using TACAN to refer to both the true TACAN and the DME transponder that is often co-located with a VOR. Feel free to correct me if I misunderstand.)

I imagine they'll keep the DME facilities open that are part of the Jet-airway system, but even with the current DME facilities, there are alot of areas in the Southwest where you could not maintain reception on the minimum two stations at a given time that are required for DME/DME. IOW, even if you did install a DME/DME system in a GA airplane, there would be alot of areas where you wouldn't have any navigation reception at the altitudes we fly.

It is also more than just having two separate DME units installed - you need an insturment that can take the two DME inputs and process the postion so that the pilot can see where he is.

DME/DME works essentially like determining position with radar arcs that we use occasionally in the maritime world when navigating near land. If you know the distance to two different known points, you can plot arcs to each and where those arcs intercept is your fix. You could manually do it in the air with a sectional and a compass, but it would be a pain in the arse and really not very practical.
 
They mentioned DME/DME/IRU in the draft linked in the OP, too.

1) how many GA aircraft have dual DME, which I presume is required for this, much less IRU? Most of the planes I've flown are using GPS to substitute for DME. (Admittedly a small sample)
We have DME/DME but no IRU. As I understand DME-DME, it takes the distance from two or more stations and calculates your position that way. It's not as accurate as GPS as noted in the link I posted, but neither was LORAN. This is what our checklist says if GPS1 and GPS2 are both inactive.

GPS 1 and/or 2 INACTIVE

This message is displayed when one or both GNSS sensors become inactive. FMS position will continue to be computed from the remaining GNSS sensor, DME/DME, VOR/DME or optional IRS information.

• If Both GNSS Sensors are Inactive
1. Do not use FMS navigation for approach.
2. Execute missed approach procedure if on an RNAV (GPS) or RNAV (RNP) approach procedure.
PROCEDURE COMPLETED
So according to that you could use area navigation for everything except the approach.

2) A DME requires a navigation source to measure from, right? If they decommission the VORs, I presume they'll be decommissioning the TACAN, too, so what is the DME measuring to? Don't there need to be two TACANs within range to use DME/DME? (And I'm being a little loose with terminology here. I think that I'm using TACAN to refer to both the true TACAN and the DME transponder that is often co-located with a VOR. Feel free to correct me if I misunderstand.)
I don't know if it would be correct to presume they are decommissioning the DMEs along with the VORs.
 
Yes, but if you take away the VORs.....what'ya gonna use other than the GPS to navigate the route?

That's what I'm referring to. If they get rid of VORs, I'm going to guess that at least 75% of the current GA fleet will be incapable of IFR flight.

(this discussion is assumed to be about enroute nav)

Unless things have changed in the past couple of years, you [edit: won't shouldn't] get a GPS IFR routing that isn't in radar coverage. So, I'm thinking that if GPS goes away, you still have the option for radar routing. Workload permitting. (and, no, I don't think this is the smartest approach -no pun- to dealing with the possibility of losing GPS)
 
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(this discussion is assumed to be about enroute nav)

Unless things have changed in the past couple of years, you won't get a GPS IFR routing that isn't in radar coverage. So, I'm thinking that if GPS goes away, you still have the option for radar routing. Workload permitting. (and, no, I don't think this is the smartest approach -no pun- to dealing with the possibility of losing GPS)

Only problem with that is that unless the FAA changes it's interpretations of 91.205 (d), I don't think that relying on ATC radar vectors is going to satisfy the requirement for 'navigation equipment suitable for the route to be flown. '

So, back to my original point. If this really happens, what do we really have? Sounds like if you want to keep using the system, you best start saving for the Garmin install.
 
Only problem with that is that unless the FAA changes it's interpretations of 91.205 (d), I don't think that relying on ATC radar vectors is going to satisfy the requirement for 'navigation equipment suitable for the route to be flown. '

So, back to my original point. If this really happens, what do we really have? Sounds like if you want to keep using the system, you best start saving for the Garmin install.

The problem is these systems are just too **** expensive. It's simply not worth it for an airplane that's worth less than $30,000.

ADS-B out, with the GPS requirement. Wait until the requirement comes out for the digital comm radios. What's the expected life of these new products? Will any of them actually last anywhere near as long as the stuff they are replacing?

My airplane is going to be converted to salvage parts.
 
One of the things that has surprised me the most about aviation in the past 10-20 years is the sophistication of avionics installed in small GA airplanes. Since the time I was flying them regularly when GPS (and LORAN) was considered new technology and a luxury, now it seems that everyone has GPS, at least of the handheld variety. I don't see any reason, then, why technology such as DME/DME wouldn't be developed also if people saw a need for it.
 
One of the things that has surprised me the most about aviation in the past 10-20 years is the sophistication of avionics installed in small GA airplanes. Since the time I was flying them regularly when GPS (and LORAN) was considered new technology and a luxury, now it seems that everyone has GPS, at least of the handheld variety. I don't see any reason, then, why technology such as DME/DME wouldn't be developed also if people saw a need for it.

DME/DME already exists and predates GPS. An area nav system can use DME/DME as a nav source.
 
DME/DME already exists and predates GPS. An area nav system can use DME/DME as a nav source.
I know that. See post #22. What I'm saying is that if there is enough demand, that avionics could be developed for smaller GA airplanes, just like the improvements in avionics in the past 10-20 years.
 
I know that. See post #22. What I'm saying is that if there is enough demand, that avionics could be developed for smaller GA airplanes, just like the improvements in avionics in the past 10-20 years.

I just don't see that happening. It is more than an avionics issue. Due to the reception limitations of DME, it is only suitable for high altitude enroute nav. It is going to be far more feasible for GA to pay for the GPS installs than for the government to install enough DME stations.

Even if I had a DME/DME in the airplanes I fly, I could not reliably navigate between San Diego and Phoenix at 10,000 feet with it based on the current DME stations.
 
I just don't see that happening. It is more than an avionics issue. Due to the reception limitations of DME, it is only suitable for high altitude enroute nav. It is going to be far more feasible for GA to pay for the GPS installs than for the government to install enough DME stations.

Even if I had a DME/DME in the airplanes I fly, I could not reliably navigate between San Diego and Phoenix at 10,000 feet with it based on the current DME stations.
I didn't mean for DME/DME to replace GPS. I was just addressing some of the fears people have about GPS becoming inop for some reason. That's the reason many people wanted LORAN kept as a backup. I didn't feel that way because most LORAN receivers installed in airplanes I flew weren't working anyway and were as good as boat anchors.
 
I didn't mean for DME/DME to replace GPS. I was just addressing some of the fears people have about GPS becoming inop for some reason. That's the reason many people wanted LORAN kept as a backup. I didn't feel that way because most LORAN receivers installed in airplanes I flew weren't working anyway and were as good as boat anchors.
Ok, I got ya
 
Unless things have changed in the past couple of years, you won't get a GPS IFR routing that isn't in radar coverage.
Source? I haven't seen that to be the case in real world ifr...
 
Source? I haven't seen that to be the case in real world ifr...

Where are you receiving IFR clearances off airways and beyond navaid usable distances outside of ATC radar coverage?
 
Where are you receiving IFR clearances off airways and beyond navaid usable distances outside of ATC radar coverage?
His statement didn't say beyond navaid usable distances. It said GPS IFR routing without radar coverage.

I've been cleared between KLNK and KTOB gps direct several times and there is a good portion of that which is non-radar requiring position reports (at 5 and 6 thousand). There are VORs within range but they aren't being used for primary navigation.

The controllers (MSP Center) in this case, have me give position reports as either distance remaining or abeam something.
 
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Since the time I was flying them regularly when GPS (and LORAN) was considered new technology and a luxury, now it seems that everyone has GPS, at least of the handheld variety.
The problem is, FAA requires something more expensive if you want it to count.
-- P
 
His statement didn't say beyond navaid usable distances. It said GPS IFR routing without radar coverage.

How would you define a "GPS IFR routing"?

I've been cleared between KLNK and KTOB gps direct several times and there is a good portion of that which is non-radar requiring position reports (at 5 and 6 thousand). There are VORs within range but they aren't being used for primary navigation.

The position reports required by a route outside of radar coverage are the compulsory airway fixes or navaids making up the assigned route. A route not composed of airways or navaids within the usable limits is not a valid route outside of radar coverage.
 
How would you define a "GPS IFR routing"?
I would define a GPS IFR routing as a routing which requires RNAV to accomplish. It certainly seems like a GPS DIRECT off-airway route between two fixes would qualify.

The position reports required by a route outside of radar coverage are the compulsory airway fixes or navaids making up the assigned route. A route not composed of airways or navaids within the usable limits is not a valid route outside of radar coverage.
There is nothing to indicate to me as the pilot that there is no radar coverage on a portion of that route. Since there is nothing to indicate it I file direct. I'm cleared direct. At some point I drop off radar and that is how they choose to handle it. It seems like radar coverage is particurally weak around Pocahontas. I'd guess there is at least 20 miles of no coverage - maybe even more like 40.

I've found radar coverage to be particularly weak in the northwest Iowa area. There are certainly aircraft flying off-airway via RNAV outside of radar coverage from time to time in this region.

Back to my original question, what is the source?
 
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