What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Is it time to forgo VHF navigation?

DCBrown198

Active Member
Patron
With the world rapidly moving to a GPS/RNAV enroute and approach environment I'm struggling with whether to even install VHF nav capability into the airplane.

I did a quick search of airports in my home state of Texas. There are RNAV approaches overlying most if not all of the VHF based ones - including LPV approaches to all of the existing ILS approaches.

The plan is to slowly decommission VORs and ILSs over time.

I can go everywhere I want to in the clouds today using RNAV and get down low with LPV capability.

Sure would be nice to forget a couple of antennas.

Anyone else been pondering this?

David
 
Lots of IFR in the -10 over the years and never ran into a GPS outage but installed antennas and radio just in case. Just my experience and don't take this as a recommendation.
 
I'm years away from an avionics decision, but I've been thinking about the same thing.

Assuming that the satellite constellation stays intact, pretty much the only practical issue I can think of is that approach will vector you closer in to intercept final on an ILS than they will on a GPS based approach.

Having said that, maybe I'm just old, but it makes me queasy to think about putting all of my eggs in the GPS basket if I'm really shooting an ILS down to minimums. If I was buying a panel today, it would have a Nav in it.

Edit: actually, I just thought of another reason: If you need to file an alternate I believe it's gonna have to be to LNAV minimums if you don't have an ILS (may have to look that one up, but I think that's right).
 
Last edited:
I like my radios. Redundancy is nice. Also alleviates stress if you can confirm your position with a different system.
 
Just me

I still get concerned about out a gps outage. Seems it is possible and still happens occasionally in the desert out west. Dont know what the future holds so I am putting it in. Besides, I figure it is an easy way to get a different type of IFR approach for currency.
 
I wouldn't bother, except for one little detail. I hope to start my instrument training and I need the VOR/ILS for the training and checkride.

I'll be installing an Archer wingtip antenna. No real weight gain, other than the cable.
 
Exactly what I did (no vor/ils). I'm GPS only equipped. But I have my own personal IFR mins that are higher than standard. Hard IFR in single-engine just isn't smart, IMHO.

The few times I lost a GPS signal, it was merely a few seconds each time. And we are talking a handful of times over the course of 30+ years of flying.
 
Consider your own equipment failure too. I had the antenna for my 430W fail while dodging clouds in sketchy VFR. It's unnerving when that warning pops up saying your GPS took a dump. I spent some anxious moments breaking the pairing between the 430W and 796 so I could use the 796 as a stand alone. I could have and should have had my 2 NAV radios setup for backup. I do now.
 
I'd say skip the VHF. Just one opinion and bear in mind I rarely get enough "real" approaches to not have to go up for some hood time every 6 months. Maybe I'd feel differently if I did more IFR flying...? Hard to say.

I have a NAV/COM/GS and Garmin WAAS receiver. The RNAV came later and the ILS takes so many fewer button pushes that I kept on flying ILS approaches for years before finally buckling down and learning the right buttons to push for RNAV approaches. Now I virtually never use the VOR or ILS except on currency flights.

Yes there's the redundancy question but that should be weighed against the added complexity, cost and weight. Backup can be a portable GPS, a handheld VHF radio with VOR, and sectional chart.
 
I can't fault one for skipping a navigation radio. But, I still bought and installed one one. Guess I am officially an old man.
 
VFR flier here, but still, anyone use a compass? When VORs came out you had, what, ADF, maybe you had Loran, but the lowly compass was always there.
 
Sporty's Handheld

I have a full Garmin G3X and GTN625 panel and no ILS or VORs, Been flying for two years and never encountered any issue with only using GPS.

When I built my RV9 I considered the need for a VOR/ILS panel as that was all I had used for years of travel in IMC from Alaska to the Bahamas and everywhere in between. Very much a steam gauge guy all that time.

When I built the RV I decided to go only GPS, given what the future was looking like. I felt it was time for me to learn how to use a glass panel and shoot an LPV, (whatever the **** that was). I spent a lot of time getting up to speed on the new technology and couldn't be more pleased with the results.

Back to the Sporty's hand held..... I purchased a Sporty's SP-400 Handheld NAV/COM as a backup for the glass panel and the GPS. I actually flew a couple of ILSs with it and it works and provides a way to track a VOR and fly an ILS if the GPS goes way while I'm up there, or my backup alternator and battery, and the batteries in my iPad and G5 all decide to quit working at the same time.... :-(

Just my approach to not needing green needles.
 
Without an ILS receiver legally you can't file where the only usable approaches for you are LPV approaches to LPV minimums if the weather is below non-precision alternate minimums (800 ceiling 2 miles viz.)

This is the gotcha since LPV are non-precision approaches, therefore non-precision alternate minimums apply.
 
Without an ILS receiver legally you can't file where the only usable approaches for you are LPV approaches to LPV minimums if the weather is below non-precision alternate minimums (800 ceiling 2 miles viz.)

This is the gotcha since LPV are non-precision approaches, therefore non-precision alternate minimums apply.

Can you please provide the applicable FAR that supports this statement?

Thanks,

Jeff
 
My Garmin 650 has an input port for a VOR/ILS antenna. So, all it cost me for the redundancy was <20 feet of coax and an Archer antenna in the wingtip. Seemed worth it to me. YMMV
 
Without an ILS receiver legally you can't file where the only usable approaches for you are LPV approaches to LPV minimums if the weather is below non-precision alternate minimums (800 ceiling 2 miles viz.)

This is the gotcha since LPV are non-precision approaches, therefore non-precision alternate minimums apply.

I may be wrong, but I think you mean LNAV, not LPV. LNAV is a non-precision approach - no vertical guidance. LPV is what you get with a WAAS receiver, which does provide precision approaches.
 
Last edited:
Take a look at this current NOTAM centered off the Raleigh Durham, NC VOR (RDU221/053). Just food for thought.

GPS (FTBRNC GPS 19-60) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVAILABLE WI A 82NM RADIUS CENTERED AT 350722N0792154W (RDU221053) FL400-UNL, 83NM RADIUS AT FL250, 82NM RADIUS AT 10000FT, 71NM RADIUS AT 4000FT ABOVE GROUND LEVEL, 16NM RADIUS AT 50FT ABOVE GROUND LEVEL. SEE TEXT - SEE TEXT, DAILY 1200-2200, 26 AUG 12:00 2019 UNTIL 30 AUG 22:00 2019. CREATED: 23 AUG 21:44 2019
 
Last edited:
Without an ILS receiver legally you can't file where the only usable approaches for you are LPV approaches to LPV minimums if the weather is below non-precision alternate minimums (800 ceiling 2 miles viz.).

This statement is misleading. You do not need an ILS to file to an airport with WAAS GPS only approaches (LPV, LNAV/VNAV, LNAV, etc). If the WX is below 800/2 then you'll need an alternate. The alternate can be GPS but flight planning must be based on flying the RNAV (GPS) LNAV or circling minima. If you're going GPS only (which I am) then you'll have to have WAAS GPS, TSO-C145 or TSO-C146. You're GTN 650, 430W, GPS175 meet these requirements. AIM 1-1-18 para 9 (a).

Jeff
 
FWIW I have lost GPS several times flying jets and one time it lasted almost an hour. Guys down low with GPS only were all asking for vectors as they were blind. That convinced me to have VHF nav capability in my RV.
 
I may be wrong, but I think you mean LNAV, not LPV. LNAV is a non-precision approach - no vertical guidance. LPV is what you get with a WAAS receiver, which does provide precision approaches.

When I was studying this I remember being surprised that LPV was not an PA (Precision Approach) and was considered an APV (Approach with Vertical Guidance). Then I started looking at some ICAO approach classification charts and LPV was listed under both APV and PA but under different Types of approaches......Can we get more confusing please?:D
 
I may be wrong, but I think you mean LNAV, not LPV. LNAV is a non-precision approach - no vertical guidance. LPV is what you get with a WAAS receiver, which does provide precision approaches.

LPV is still a non-precision approach. LPV and APV are synonymous.

From AIM 1-1-20. Wide Area Augmentation System (WAAS)

b. Instrument Approach Capabilities
1. A new class of approach procedures which provide vertical guidance, but which do not meet the ICAO Annex 10 requirements for precision approaches has been developed to support satellite navigation use for aviation applications worldwide. These new procedures called Approach with Vertical Guidance (APV), are defined in ICAO Annex 6, and include approaches such as the LNAV/VNAV procedures presently being flown with barometric vertical navigation (Baro-VNAV). These approaches provide vertical guidance, but do not meet the more stringent standards of a precision approach. Properly certified WAAS receivers will be able to fly these LNAV/VNAV procedures using a WAAS electronic glide path, which eliminates the errors that can be introduced by using Barometric altimetery.
 
jIj5g.png
 
For what it's worth

I think it depends on the kind of flying you will do.

I fly IFR a large percentage of the time, but with fairly conservative personal minimums. So the odds that I'll have to get down low AND that GPS will be unavailable at that moment are extremely low. So, although I've got ILS capability with a 430W, I certainly wouldn't feel endangered if I had only WAAS plus a handheld with nav capability.

On the other hand, if I were out there routinely shooting approaches to minimums, I'd definitely want the full monty.

With the world rapidly moving to a GPS/RNAV enroute and approach environment I'm struggling with whether to even install VHF nav capability into the airplane.

I did a quick search of airports in my home state of Texas. There are RNAV approaches overlying most if not all of the VHF based ones - including LPV approaches to all of the existing ILS approaches.

The plan is to slowly decommission VORs and ILSs over time.

I can go everywhere I want to in the clouds today using RNAV and get down low with LPV capability.

Sure would be nice to forget a couple of antennas.

Anyone else been pondering this?

David
 
All GPS around Savannah, GA, is about to get blown away by a Navy carrier group. And although it's rare, GPS is also susceptible to some kinds of solar interference.

This exercise may affect GPS down to 50 ft AGL from roughly Daytona Beach, FL up north to Charleston, SC

So the choices then are pilotage or VOR...

FLIGHT ADVISORY
GPS INTERFERENCE TESTING
CARRIER STRIKE GROUP (CSG4) 19-03
30 August ? 05 September 2019 Off The Coast of Savannah, GA
GPS testing is scheduled as follows and may result in unreliable or unavailable GPS signal.
A. Location: Centered 311230N0795830W or the SAV VOR 139 degree radial at 84NM.
B. Datesandtimes:(DatesandtimesarebasedonGMT(Z).): 30 AUG 19 1800Z ? 2200Z
05 SEP 19 1600Z ? 2000Z
 
Correct. So you cannot fly to an alternate using minimums lower than 800/2 if you just have LPV. You can if you have an ILS. This is very straightforward.

I believe the regs state that you cannot "FILE" to that alternate in your example. Once in the air, you can go where ever you think is best, without limitation from the regs, beyond the standard approach minimums. Those limitations are based upon flight conditions and not forecasted or reported conditions. Most LPVs are 200/.5 to 400/1.

Larry
 
Last edited:
I just wrestled with this decision all week at AirVenture this year. With the introduction of the Garmin 175 line, I decided to forego the VHF capability of the GTN 650 for the economy GPS navigator. As a mean of mitigation, I bought a hand-held VHF/VOR/ILS from Sporty's for $400 that will give me an emergency back-up for not only nav, but comm too.
 
I believe the regs state that you cannot "FILE" to that alternate in your example. Once in the air, you can go where ever you think is best, without limitation from the regs, beyond the standard approach minimums. Those limitations are based upon flight conditions and not forecasted or reported conditions. Most LPVs are 200/.5 to 400/1.

Larry


I agree. File IFR rules apply before takeoff. Once airborne, do can fly wherever you want.

On another note, I enjoy being able to flie to destinations (and alternates) with both GPS and ground based Navs. There may be times when the land based nav is a better choice (ie wind, terrain etc). Just my opinion
 
Last edited:
So there's the legal aspects to this, which is clear.

There's also the aspect of being wise. So if your nice GPS unit quits working while in the soup being radar vectored, because things fail, which one has to assume will eventually happen, I certainly would feel more comfortable with a separate VOR/ILS.
 
Oh my. A lot of confusing misinformation. Review:
1. If you file IFR to Kxyz, then, unless kxyz has an approach you can use, and, +-1 hour of your ETA, the forecast calls for a 2000? ceiling and 3 miles visibility, or better, then you must file an alternate (people call this the 1-2-3 rule).
2. The alternate airport you file to must have a forecast that indicates the weather will be better than 600? ceiling, 2 mile visibility, if it has an ILS and you have ILS equipment; for all other approaches, you need to have 800? - 2 miles. (Military PAR approaches are also 600?-2). Many airports have ?non-standard? alternate minimum wx requirements. You need to check.
3. You must carry enough gas to fly to the destination, then to the alternate, plus 45 min reserve still left.

It?s really #3 that is usually limiting. You may file (and shoot the approach, but not below minimums) to an airport that?s 0-0. But you cannot depart unless you have enough gas to satisfy #3.
 
To answer someone?s question: Yes, ?LNAV+V? is a Garmin invention, not to be confused with LNAV/VNAV. LNAV +V will show an advisory glide slope designed to keep you at or above LNAV minimum altitudes. But it is an LNAV approach, LNAV minimums apply. Using the glide slope is optional.
 
Be sure to keep REALLY fresh batteries in it at all times

Ask me how I learned this. :)

I just wrestled with this decision all week at AirVenture this year. With the introduction of the Garmin 175 line, I decided to forego the VHF capability of the GTN 650 for the economy GPS navigator. As a mean of mitigation, I bought a hand-held VHF/VOR/ILS from Sporty's for $400 that will give me an emergency back-up for not only nav, but comm too.
 
3. You must carry enough gas to fly to the destination, then to the alternate, plus 45 min reserve still left.

It?s really #3 that is usually limiting. You may file (and shoot the approach, but not below minimums) to an airport that?s 0-0. But you cannot depart unless you have enough gas to satisfy #3.

THAT I believe is a key point, and I would say that you can mitigate the relative risk of going GPS only IFR by just topping up your tanks. When flying IFR, I feel so much better if I know I could get to some place with good weather, if need be.
 
What Ron K said

I don't have the panel space, the money, or the gross weight to install something I will likely never use. Like Ron K posted above, I carry a handheld for Comm/VOR backup. I also carry sectionals. I don't fly IFR.
 
I don't have the panel space, the money, or the gross weight to install something I will likely never use. Like Ron K posted above, I carry a handheld for Comm/VOR backup. I also carry sectionals. I don't fly IFR.

Yes well, that of course is a whole other discussion. I never quite understood why someone would load their plane up with IFR equipment if they only ever intend to fly VFR. The "IFR capability just in case" scenario is just adding unneeded weight, cost and complexity to your plane and can provide a dangerously false sense of security if you don't intend to go ahead and get the rating and stay current. I once lost a friend that way... different story.
 
GPS owner & operator

Let's not forget that the GPS system we so enjoy is owed & operated by the U.S Military (Air Force) and thankfully they let us play with their "cool toy" most of the time but on occasion sometimes they choose not to share. So when they take their "BALL" and go home you had better have a spare to finish the game and the spare in this case should be VHF navigation capability.
 
Vor alternates

So before I went to Osh this year, i thought the only way to get VOR was to use a GTN 650. However at Osh I discovered that there is a Radio GNC 255 that also has VOR capability. So this may be an option to allow the ?cheaper? GTN625 and still get VOR.
I will probably still end up with a GTN 650 and remote radios to save panel space.
 
Let's not forget that the GPS system we so enjoy is owed & operated by the U.S Military (Air Force) and thankfully they let us play with their "cool toy" most of the time but on occasion sometimes they choose not to share. So when they take their "BALL" and go home you had better have a spare to finish the game and the spare in this case should be VHF navigation capability.

If they take their ball and go home the US airspace system will collapse and I suspect GA IFR flying will be suspended entirely until the system is restored.
 
If they take their ball and go home the US airspace system will collapse and I suspect GA IFR flying will be suspended entirely until the system is restored.

And as we saw during 9/11, they will do it as long as required, but there will be pressure mounting within a few days to get the airspace going again. We are a nation dependent on fast transport.
 
VFR I would forgo VOR/LOC/GS/MB/ADF. You can always add it later if you desire or buy the latest greatest IFR certified GPS. VFR GPS have all kinds of IFR Nav data. I suppose in an emergency you could use it...

All the talk of GPS going down? Can you say dead reckoning and pilotage. There is always the cheap handheld with VOR/LOC/GS for emergency.

IFR - ILS Cat 1 - 1/2 mile and 200' ceiling as low as 1800 RVR and 100 feet HAT. IFR GPS RNAV + WAAS may get close to precision Cat 1 ILS, but ILS is still king of the precision approaches to me. I don't think they are going away soon. ILS does not require avionics database updates or button pushing. Dial the Freq, put the front course in and drive in.

With that said IFR "Lite" with an all in one VOR/LOC/GS/MB with VFR GPS could be cheap IFR capability for occasional light IFR. I enjoyed the challenge of NDB approaches or intercepting and tracking a radial or localizer.
 
Last edited:
Airlines don?t use GPS for enroute navigation. Shutting down the system would have little to no effect on airline travel.
 
Airlines don?t use GPS for enroute navigation. Shutting down the system would have little to no effect on airline travel.

Ahhh..but when (if) NextGen kicks in for real, it (ADS-B) will be the ONLY way of separating traffic because radar goes away. That is, if you believe the plan....
 
Gps

“...
Airlines don’t use GPS for enroute navigation. Shutting down the system would have little to no effect on airline travel...”

I’m not sure I would go that far...we use gps to continuously update the IRS so yes we do use it...but, as you said, loss if gps wouldn’t have much effect...
 
Last edited:
Airlines don’t use GPS for en-route navigation. Shutting down the system would have little to no effect on airline travel.
You are correct but would not say no effect.

It depends... a typical Boeing or Airbus has three IRU (inertial reference unit). They are totally independent of any outside navigation using laser rings and accelerometers. However that position (voted on by three IRU's) is mixed with GPS and terrestrial navigation (DME, LOC, VOR's) to get a FMS (Flt Management Sys) position. FMS position ranks the navigation sources and presents on the PFD (primary flight display). I can tell you the FMS ranks GPS very high except maybe on an ILS approach when the FMS will update on LOC and DME.

With that said for domestic navigation, more than IRU position is needed. If no GPS the FMS auto-tunes in all available terrestrial navigation units. Some of the regional jets need GPS I believe. So they would be grounded unless they can revert back to full steam (ground based Nav).

Would it affect operations? If the airplane has a destination or required alternate that requires GPS, yes it would effect operations. A GPS based approach has no IRU/FMS or ground based NAV alternate.
 
Last edited:
Airlines don?t use GPS for enroute navigation. Shutting down the system would have little to no effect on airline travel.

Most airliners use GPS for nav now. They can use LNAV which is based off VOR DME?s as a backup and will downgrade to IRS/INS as a last resort. Loss of GPS would however cause many system wide problems including GPS approaches and arrivals and RVSM airspace. Shutting down GPS has far greater implications beyond aviation. It would be a national disaster.
G
 
Back
Top