VOR impact study

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Laura_D

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Laura_D
Hi all, I'm currently involved in a research project and am hoping the community here can help me out. I'm sure most of you are aware that the FAA is planning to significantly reduce the number of operational VOR's by 2020, in conjunction with NextGen implementation. I'm interested in the impact this may have.

It is my understanding that many pilots are already using GPS as their main method of navigation but rely on VORs as a back up. I am aware of the concerns regarding the reliability of GPS, including the recent LightSquared interference issues. I know another major concern, expecially for GA pilots, is the cost of the avionics that will be required for NextGen.

Besides these concerns, what other issues might be involved with this proposed loss of VOR service? Any input would be appreciated! :)
 
I'm curious, what's the research project for?
 
OffCenter said:
For what it's worth, I don't have a gps. I use VORs regularly.
...and I'm a bit upset that they are eliminating them.
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Of the three planes in our club, only one has an approach certified GPS. I depend on VORs for navigation. Eliminating VORs is not going happen without significant costs of adding GPS equipment to aircraft not already so equipped.
 
They could reduce many of the VOR's but, I still think it is going to increase the workload for ATC. As more of the Terminal and low frequency VORs become decommissioned there will be an ever increasing number of airports that loose their ability to serve the widest amount of traffic possible. That is going to mean either ATC is going to have to spend more time vectoring aircraft for visual approaches, or have more cases of people going to nearby airports to get below a layer then canceling to proceed VFR to their destination airport. That's a problem since it will increase the risk of CFIT accidents, and ATC will need to be move involved with arriving traffic trying to get vectors for a visual approach. GPS reduces ATC workload, but still requires monitoring for direct routes. Not a big problem at all, but if there isn't a VOR for all the other aircraft whom are non-RNAV equipped then ATC is going to have to watch their course much more closely in case their initial vector was not enough to account for the winds aloft.

I don't see enough owners/aircraft becoming equipped with GPS within the time frame that the FAA wants to decommission many of the VORs to NOT affect the NAS. Our GA fleet is old enough that I think VORs are going to be an integral part of the NAS until at least 2050 -- at which point I think the cost of most GPS units or their future replacement units will become affordable enough for the masses.

Right now, I still see GPS as the 50" big screen. Everyone loves it, it is very popular to have in the home, but people are still slowly buying their FIRST big screen. If the FAA would be willing to subsidize GA like they do the airlines then NextGen could be utilized starting next week..... it isn't like people are refusing to buy GPS units because they don't like them :). It always has been and always will be all about the Benjamin's :D
 
I used Foreflight VFR today but still planned VOR to VOR and tuned them as a backup. It's nice to see the DME agree with the consumer grade GPS, etc. And we're legally still a /A equipped aircraft for IFR, of course. And the autopilot, even as bad as it is, will track a VOR signal on either Nav 1 or Nav 2.

This is another problem with GPS. I see a lot of aircraft with no redundancy... Only one receiver/display.

With VOR OBS's, there's usually two separate systems. If it goes out in-flight, you'd u

Would we like an approach-certified GPS? Sure, if there were any real competition in that market. Right now the long-bets all go to Garmin.

To "Garminize" our panel is somewhere in the range of $10000 which buys a lot of avgas over the next 9 years.
 
Dean V said:
I doubt total illimination is the FAA's goal.
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This isn't the lead-in to a series of "How many FAA employees does it take to screw in a lightbulb?" jokes, is it? :D
 
So, here's my question... why do they want to decommision them anyway? They don't use that much electricity do they? Do they really require expensive and difficult maintenance?
Frankly, they should leave them in place as there are a lot of folks who use them and they are a good back up to GPS not working ....
 
Jeanie said:
So, here's my question... why do they want to decommision them anyway? They don't use that much electricity do they? Do they really require expensive and difficult maintenance?
Frankly, they should leave them in place as there are a lot of folks who use them and they are a good back up to GPS not working ....
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Why? Because they think they can snocker other agencies into paying for the operation/maintenance of the VOR system.
 
Jeanie said:
So, here's my question... why do they want to decommision them anyway? They don't use that much electricity do they? Do they really require expensive and difficult maintenance?
Frankly, they should leave them in place as there are a lot of folks who use them and they are a good back up to GPS not working ....
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In the FAA's defense, were they sayin the same thing about NDB's when they first started talking about decommissioning them? (i'm a youngin, so i really don't know) (I know they were about LORAN...)

I'm sure they will always have this problem when new technology becomes popular and older stuff "fades" away. Users throwin a fit because it means costly upgrades. Not saying I wouldnt be complaining...
 
The old saying you learned back in elementary school applies here as well. "Don't put all you eggs in one basket." Decommissioning all VOR's with no backup system will create navigation issues when an unexpected problem with the GPS satellite system crops up. Personally, I think we should have kept LORAN as a GPS backup. Only a few stations to maintain. The box in the airplane could have easily handled both.
 
VORs will go the way of NDBs. Pilots will resist, because they don't want to spend the money on upgrading their equipment. However, I think that by 2020 elimination of a number of VORs will be a logical step. At my airport, there are only a few IFR aircraft that don't have GPSs in them. In fact, all the aircraft at my airport that actually fly IFR on a regular basis have an approach-certified GPS.

The regionals may be a bigger concern, as I don't know how many of the 1900s, Dash trash, 340s, etc. out there still don't have approach-certified GPSs installed. However as those aircraft become retired, they'll be replaced with aircraft that are GPS-equipped.

Eliminating the ILS/Localizer will be a bigger issue than eliminating VORs. I see far fewer aircraft equipped with WAAS GPSs. Most aircraft (and airports) I fly into depend on an ILS for a precision approach.

What I notice is that the majority of the people who insist we need to keep VORs because they can't afford an IFR GPS are the people who don't fly IFR in their aircraft a significant amount, and as such don't make up a significant percentage of the population that uses the tools.
 
So, what sort of costs do VORs have to maintain? Just wonderin'
 
Ted DuPuis said:
VORs will go the way of NDBs. Pilots will resist, because they don't want to spend the money on upgrading their equipment. However, I think that by 2020 elimination of a number of VORs will be a logical step. At my airport, there are only a few IFR aircraft that don't have GPSs in them. In fact, all the aircraft at my airport that actually fly IFR on a regular basis have an approach-certified GPS.

The regionals may be a bigger concern, as I don't know how many of the 1900s, Dash trash, 340s, etc. out there still don't have approach-certified GPSs installed. However as those aircraft become retired, they'll be replaced with aircraft that are GPS-equipped.

Eliminating the ILS/Localizer will be a bigger issue than eliminating VORs. I see far fewer aircraft equipped with WAAS GPSs. Most aircraft (and airports) I fly into depend on an ILS for a precision approach.

What I notice is that the majority of the people who insist we need to keep VORs because they can't afford an IFR GPS are the people who don't fly IFR in their aircraft a significant amount, and as such don't make up a significant percentage of the population that uses the tools.
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Or folks aren't happy about losing the ability to navigate in IMC should the GPS signal be lost.
 
jesse said:
Or folks aren't happy about losing the ability to navigate in IMC should the GPS signal be lost.
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That's the biggest reason for keeping VORs. However if you go to certain areas where there are large numbers, there are still a good number that could be eliminated without having an impact on the ability to do that.
 
I was returning on Tuesday from FTG and PUB VOR was out. That left a considerable gap at non-oxigen altitudes. There never was an opportunity to get lost, due to easily referenced terrain features, but I almost busted Delta around KPUB by drifting right, and had to make a left turn when I realized what I am looking at.

I have AV8OR, but its battery life is pathetic and one of airplanes I rent has no cigar lighter outlet (well actually its VOR receiver is broken too...).
 
jesse said:
Or folks aren't happy about losing the ability to navigate in IMC should the GPS signal be lost.
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Jesse hit the head on the nail.

GPS-jamming and GPS-spoofing (aka "GPS denied") are real issues. This can include interference to GPS reception (as well as intentional disruption). The military is moving to M-code to overcome some issues with GPS, but there is still a very real possibility of jamming or interference. All those NOTAMS we see for GPS reception in certain areas of the US are about testing military GPS systems for interference resistance.

One of the things I'm grappling with in replacing my #2 NAVCOM/DME and #2 GPS with a 430W is finding a used DME for sale at a reasonable price. I don't really want the weight/size of a KNS80: a used KN-62 or 64 is more like it. Were Narco still supported, I might consider a used -890 or iDME-891. I still see DME as a virtual requirement given how fragile GPS can be.
 
wsuffa said:
Jesse hit the head on the nail.

GPS-jamming and GPS-spoofing (aka "GPS denied") are real issues. This can include interference to GPS reception (as well as intentional disruption). The military is moving to M-code to overcome some issues with GPS, but there is still a very real possibility of jamming or interference. All those NOTAMS we see for GPS reception in certain areas of the US are about testing military GPS systems for interference resistance.
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And VORs can't be jammed? The earth is the biggest jammer of VOR signals, and they're plenty susceptible to errors and other issues, which we forget about. Plus, as ground-based items, it's much easier to find them and physically destroy them. After all, I don't see them as being heavily guarded.ooo

Just over the accelerated training of my last student (all /A) we had a VOR go out on us while we were using it, and he was amazed how many VORs have unusable radials below certain altitudes due to terrain features.

GPS has failed on me... zero times, and it works when I power up the plane on the ground.
 
Ted DuPuis said:
And VORs can't be jammed? The earth is the biggest jammer of VOR signals, and they're plenty susceptible to errors and other issues, which we forget about. Plus, as ground-based items, it's much easier to find them and physically destroy them. After all, I don't see them as being heavily guarded.ooo
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No question they can be jammed (ILS, too, by the way). Electronic jamming can happen with something as simple as a TV antenna booster amplifier (cable TV has reduced that cause quite a lot). But since the ground-based navaids are closer, operate at higher power, and use analog transmission, the impact tends to be less widespread. At the same time, in many areas there are alternate ground-based navaids that can be used. It takes higher power to intentionally jam a VOR signal.... and that higher power makes the jammer easier to track. I helped track down a transmitter that was jamming the ISP ILS one time - that one turned out to be a pirate radio transmitter operating at 108.1 MHz (in the days of analog-tuned FM radios....). It took about a 2 hours to track, much of which was spent in traffic.

On the other hand, GPS operates at much lower power levels (or more specifically, the signal at the antenna terminal is much less). That makes it much easier to jam, and much harder to track. Try tracking down one of these. Especially if the operator were using an external antenna on a mountaintop. Or the device were in a car in a large parking lot under the LPV approach at an airport. :hairraise:

There are devices on the black market that can actually spoof GPS satellites - meaning the location information you receive is false. By transmitting a spoofed code, the GPS receiver will never know that the wrong information is present.

Just over the accelerated training of my last student (all /A) we had a VOR go out on us while we were using it, and he was amazed how many VORs have unusable radials below certain altitudes due to terrain features.

GPS has failed on me... zero times, and it works when I power up the plane on the ground.
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Agree that terrain & other obstructions is a big deal. The ARSNL2 departure from HEF is unusable on the south runways due to signal obstruction on the CSN VOR. So you get a vector instead. It's not just terrain blockage, but also multipath from nearby structures.

Neither system is foolproof, and neither system is immune. It's just with ground-based navaids one has more alternatives than with GPS alone.
 
I don't have a nav reciever in my airplane, so obviously I don't use VORs. I do have an old (non aviation) hand held GPS that I use sometimes. But even when the GPS is turned on, my primary navaid is a paper chart.

Obviously, I don't fly IFR / IMC.
 
Thank you everyone for the feedback. I'm getting a lot of good information from this thread. :)

For those of you wondering what this project is for and in the spirit of complete disclosure, I'm a NAVAIDS maintenance technician for the FAA. I maintain a variety of ground based Navigational Aids, including ILS, VOR, and DMEs. I know how this equipment works from the ground, but I'm not a pilot or an air traffic controller, so I'm not very familiar with the avionics or how you use this equipment the air. I'm currently involved in a program for emerging leaders and this research is for a group project requirement. None of the members of my group are involved in the decision making or implementation surrounding the decommissioning of VOR's. We're simply trying to determine if there are any aspects involved or ramifications this will have that haven't already been considered. We plan to report our findings to the Operations Engineering group. The decommissioning of VOR's will directly affect me as well, as VOR's are currently a large part of my workload.

To answer some of the questions brought up, we are only considering VOR's in our study - not DME, not ILS. The cost of maintaining these aging VOR's is high - I don't know what the actual national cost is, but at my facility we maintain 4 of them and a significant amount of time and money is spent on each one. This is 60's era technology and it is prone to outages. Replacement circuit cards and parts are expensive. Also, the sites themselves are often remote (mountaintop) and require maintenance of roads and grounds, backup generators, not to mention fuel and manpower. Some of them are prone to vandalism, others are prone to lightning strikes. I believe they are much more costly to maintain than NDB's. Although we have not researched the cost of maintenance for this project, I would venture a guess that VORs/TACANs are one of the most expensive FAA systems to maintain.

As to how many VOR's will be decommissioned, I've heard a figure of around 50% initially. There are somewhere in the ballpark of 1000 VOR's in the NAS. They plan to start with the ones that will have the least impact - not tied to approaches, near other VOR's, have work arounds in place, etc.

Thanks again for your time and feedback, it's much appreciated. I hope the fact that I work for the FAA :yikes: doesn't discourage anyone from posting more thoughts about this.
 
just a data point one of our local glider pilots had his GPS jammed last weekend while he was flying over I-35. Probably a trucker jamming the signal so his boss couldn't tell where he was.
 
Laura_D said:
Thanks again for your time and feedback, it's much appreciated. I hope the fact that I work for the FAA :yikes: doesn't discourage anyone from posting more thoughts about this.
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Far from it - I would expect more useful input. I, for one, am glad to see the FAA actively seeking out input from pilots.

I fly about 500 hours a year all over North America in piston twins (US, CAN, MEX). I haven't used a VOR other than to do VOR checks (which actually would be hard to do with fewer VORs) or cross-reference my position in probably 2 or 3 years, and that was only for a few months prior to the Aztec I bought getting an IFR GPS installed. The exception is for training. For that, I make my students an fly file /U or /A (no GPS).

All the planes I see that are actually working aircraft (and therefore fly the lion's share of the hours) are IFR GPS equipped. Bob Albertson probably has a better position to comment on the regional airlines. My realm focuses on piston and turbine aircraft that do not require a type rating.

The comments about VORs as a backup are very much correct, and they serve well as that. However, I also understand the practical aspect of having installations that are costly to maintain, and believe that the phasing out of VORs is another inevitable step in the progression of technology.
 
tonycondon said:
just a data point one of our local glider pilots had his GPS jammed last weekend while he was flying over I-35. Probably a trucker jamming the signal so his boss couldn't tell where he was.
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Right, but in your experience, how many times have you had problems with VORs vs. how many times have you had problems with GPS? For my 1500 hours, GPS is 0, VORs are more than I can count for far fewer hours used.
 
My thoughts: I do use VORs on a frequent-enough basis, and (at least in the Northeast) find that routings ARE airway/VOR based. Like it or not, the DC/Philly/NY/Boston corridor is based on VORs and airways. Yes, a GPS can substitute. I fly somewhere between 25 and 200 hours this year (35 hours in the last 60 days).

My preference is to program the GPS & use the roll-steering adapter to let it drive the autopilot. But I find that I use the actual VORs on a regular basis. Last Friday, my routing assignment was the 273 radial from the Linden VOR. 3 weeks ago, I had a VOR-based routing out of the Boston area that really couldn't be duplicated via GPS (enough difference between VOR and GPS to make the VOR "primary").

I agree with Ted that enroute I usually fly the GPS. And I rarely use the VOR on approaches (having said that, I have done a VOR/DME approach in the last 30 days).

I do note that *unless one has a WAAS GPS unit*, the rules (OK, AFM) still requires the ability to navigate to appropriate navaids, which in this case means VORs. I suspect that there are still many airplanes that don't have WAAS GPS units installed (so removing VORs will limit their ability if out of radar coverage).

As a backup: definitely there needs to be sufficient VORs to cover. I've had issues a few times with loss of GPS signal or loss or RAIM. And one occasion where the only GPS (a Garmin 430) on board took an error message and required reboot.

I'll also add that in the DC area VOR/DME is one of the convenient ways to verify a GPS display regarding the SFRA & FRZ.

That said, I do understand the maintenance & cost issue. I'm sure there are some VORs that can go away with minimal impact.
 
Laura_D said:
We're simply trying to determine if there are any aspects involved or ramifications this will have that haven't already been considered.
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You might want to report that at least one member of this group thinks that you could have done away with every VOR in the United States if you had kept Loran perking along. For a couple of reasons.

One, for the cost of half a dozen Loran stations you could have eliminated the entire VOR system which is what, about 600 stations.

Two, given a relatively small amount of money it is possible to build a system using broadband noise and heterodynes that will jam an area a hundred miles in diameter for VOR. Given that same relatively small amount of money it is even easier to build a system that will jam GPS for the same radius. With Loran transmitters putting out hundreds of kilowatts, no chance for jamming over any distance whatsoever.

Three, Loran is inherently distance-independent. A 3° VOR error isn't much in close, but the mileage error at 75 miles is rather large. It made no difference in Loran error WHERE the transmitter was.

Jim Weir
Flight Instructor, Commercial/Instrument Pilot Airplane & Glider
Airframe & Powerplant mechanic, Inspection Authorization
Make my living designing avionics, HF through microwave.
 
weirdjim said:
You might want to report that at least one member of this group thinks that you could have done away with every VOR in the United States if you had kept Loran perking along. For a couple of reasons.
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I don't disagree with your reasons, and that does represent another option that I would've liked as well (especially since one of the aircraft I fly has a LORAN boat anchor installed).

But my question: How many aircraft had LORAN compared to the number of aircraft that have VORs and GPSs installed? Remember to factor in flight hours, as that is important in determining the impact.
 
See post #14 -- there are two of us that would have liked to see LORAN kept.
 
FWIW - I've never had issues with VORs nor have I suddenly lost signal. I have lost GPS signal on numerous occasions for a short period of time.

It's less about the risk of jamming to me as much as it is a dependency on a single technology which is ran by humans, which means it can and will fail.
 
To get a better idea of their policy and plans, I searched and found the following DoD/DHS/DoT published PDF formatted document on the BTS web site (TLAs are us):

2008 Federal Radionavigation Plan
http://ntl.bts.gov/lib/31000/31300/31340/02_2008_FEDERAL_RADIONAVIGATION_PLAN.pdf

Sections I skimmed through that seemed interesting: 3.2.4 GPS Backup, 3.3.1 Mitigating Disruptions to Sat Nav Svs, 3.4 Aeronautical Transition Policy, and 5.1.5 on VOR and DME.

Quote from 3.4.1:

"The pace and extent of the transition to SATNAV will depend upon a number of factors, including:
• NAS performance;
• achievement of GPS and GPS augmentation systems program milestones; and
• user acceptance."

I believe the last bullet point translates to "if they ***** a lot we'll keep the old stuff running longer."
 
somorris said:
See post #14 -- there are two of us that would have liked to see LORAN kept.
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Check out the document I linked to in post 39. LORAN isn't going away (ok, LORAN-C is going away) but rather a system called eLoran (thankfully they didn't call it iLoran!) is to be implemented as a backup/complement to GPS. The intent is that it be precise enough for non-precision instrument approaches.
 
OffCenter said:
For what it's worth, I don't have a gps. I use VORs regularly.
...and I'm a bit upset that they are eliminating them.
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You will have to have some sort of GPS installed by 2020 in order to be compliant with the ADS-B requirements. :D

I have three GPS receivers in my airplane and haven't used either of the two VOR receivers for navigation in several years. I won't miss the decomissioned VORs...


...until the day GPS goes offline where I'm at.
 
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