GPS Navigation only vs with VOR/ILS

[Exec21]

I am in the beginning stages of upgrading my panel.  I primarily use GPS for nav and approaches, like most people I'm sure.  I will go 6 months without using the VOR/ILS nav/com except for checking to make sure it is still working.  My question is, are people still installing new nav/com's as part of their avionics upgrade or are people just going with GPS alone?  I am most likely going with the Dynon Skyview system and I need to decide on a GPS navigator with GPS/NAV/COM all in one or just GPS.  I know the number of VOR's and ILS approaches is dwindling.  I can see having a separate nav/com in case the GPS system goes down.  

I appreciate your thoughts on this.

[toto]

My panel upgrades have assumed a need for VOR+LOC+GS.  The FAA has a minimum operational network of VORs to allow enroute, approach, and landing with ground-based navigation, and I like having that option.

I have encountered a GPS outage once or twice, and I wouldn't want that to happen in the soup with no alternative.

https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gbng/vormon

[Fly Boomer]

14 minutes ago, Exec21 said:

I am in the beginning stages of upgrading my panel.  I primarily use GPS for nav and approaches, like most people I'm sure.  I will go 6 months without using the VOR/ILS nav/com except for checking to make sure it is still working.  My question is, are people still installing new nav/com's as part of their avionics upgrade or are people just going with GPS alone?  I am most likely going with the Dynon Skyview system and I need to decide on a GPS navigator with GPS/NAV/COM all in one or just GPS.  I know the number of VOR's and ILS approaches is dwindling.  I can see having a separate nav/com in case the GPS system goes down.  

I appreciate your thoughts on this.

I wouldn't go without the VOR/ILS NAV.  That said, I would hate to lose my ADF.  I like options.

[McMooney]

I'd be happy with 2xcom,  1 gps and 1 nav/ils

around here 50/50 chance the vor/ils you're trying to use is even available.   Honestly, i'd be more concerned flying without a gps than the nav

 

 

[ArtVandelay]

From a part’s perspective, it’s about extra $2300 to get the VOR/ILS in addition to com radio, that’s without DME. If I didn’t have GPS, I’d definitely have a DME.
I probably be happy with just 1 navigation radio, but I would be afraid buyers would expect 2, especially without DME, because almost every certified plane has 2.

[EricJ]

I like the idea of having the VOR/ILS, and they are handy as backups even just for general navigation.   From a practical standpoint, shooting an ILS without either a marker beacon or DME would be tricky, and most airplanes don't have DME any more and most airports don't have marker beacons.   An ILS could still be done in a pinch using just the altimeter, but many approaches would not be options if the GPS was down and you needed it for DME.

 

[Pinecone]

I think Garmin missed a great thing to add DME the GTN series.  Comm, GPS, VOR/LOC, plus DME would fill all the needs.

I could see having only one VOC/LOC nav, with one or two GPS navs.  But I will keep a VOR/LOC in my plance

[hubcap]

I just got my plane back from a complete upgrade. 

I went with:

WAAS GPS x2

VOR/ILS x1

Comm x2

My OCD wanted 2 of everything but I think 1 Nav should be sufficient. What’s the likelihood that my nav would happen to go down during a GPS outage?

 

[Ragsf15e]

I’m comfortable with 1 gps, 1 nav/ils and 2 comm.  bonus if the gps & nav are separate.

[PT20J]

Modern electronics has gotten so much more reliable that I'm not as concerned about failures as I used to be. I want a VLOC backup, but I don't find the need for multiple GPS. When the GNS 430 came out, it was pretty standard for installations to have two, just as everyone used to have two Nav/Coms before GPS. Garmin must have loved that!. Over time, I see fewer installations like that. (Of course, Garmin would love to sell you a GTN 750 and 650 combo). 

[AIREMATT]

8 hours ago, Fly Boomer said:

I wouldn't go without the VOR/ILS NAV.  That said, I would hate to lose my ADF.  I like options.

Like listening to the ball game on the AM dial?

[Fly Boomer]

15 minutes ago, AIREMATT said:

Like listening to the ball game on the AM dial?

Exactly!  

[DCarlton]

I’ll probably stick with 2 comm, 1 gps, and 2 nav VOR/ILS for as long as I’m flying.  I like dialing up both nav radios on an ILS and comparing response.  It’s also helpful to find a VOR cross radial from time to time.  

[hais]

I was reading the G3X POH supplement for the Mooney yesterday. Under limitations, it says IFR operations are prohibited without a valid GPS signal.

Made me wonder what the NAV is there for, looks like GPS is a single point of failure. 

[ArtVandelay]

I was reading the G3X POH supplement for the Mooney yesterday. Under limitations, it says IFR operations are prohibited without a valid GPS signal.
Made me wonder what the NAV is there for, looks like GPS is a single point of failure. 

Probably they didn’t bother getting it certified, I’d guess there’s expensive testing that has to be done. If you want it, another $4k gets you G500.

[Ragsf15e]

8 hours ago, hais said:

I was reading the G3X POH supplement for the Mooney yesterday. Under limitations, it says IFR operations are prohibited without a valid GPS signal.

Made me wonder what the NAV is there for, looks like GPS is a single point of failure. 

The ahrs in the g3x and g5 uses gps as an input to keep it properly aligned.  It can also use pitot input, but it theoretically degrades over time without gps.  Several people tested them without gps and they worked fine. @PT20J is the expert.

[rbp]

I went with a GPS/VLOC/COM GTN750xi and a GPS/COM GNC355

if I had to do it all over again, I would have spent a little extra money and gotten the GTN650 instead of the GNC355 because of the tighter integration with the 750, not for the second VLOC.

I have used the VOR receiver exactly zero times in the last year. I take that back -- I flew a VOR practice approach when I first got the panel, but I have never used it for actual navigation. I requested KABE VOR-A practice approach last week just for grins, but approach told me it was "no longer available," even though it had it it foreflight. It is however missing from airnav. Instead I flew the RNAV with a DA of 200', which was pretty *yawn*.

[hais]

10 hours ago, Ragsf15e said:

The ahrs in the g3x and g5 uses gps as an input to keep it properly aligned.  It can also use pitot input, but it theoretically degrades over time without gps.  Several people tested them without gps and they worked fine. @PT20J is the expert.

Comforting to know that it works. But also troubling not knowing how it might fail. Will there be a red X, or did we replicate the vacuum gyro failure mode? Hopefully @PT20J can share some insights.

Had I known about this limitation, I would have made a different purchase decision. With the old panel, GPS loss was a minor annoyance. With the new panel, it will be a show stopper. 

Do we need now to check GPS NOTAMs for enroute portion, not just for the approach? 

[PT20J]

Generally, all MEMS-based AHRS provide good short-term attitude solutions but suffer long-term drift. This is compensated for by using additional inputs, generally some combination of air data, GPS, and 3-axis magnetometers. Garmin goes into some detail explaining this in the G3X Pilot’s Guide, but not in the G5 documentation. However, we can reasonably infer that the products act similarly since they were designed by the same team (Team-X). 

So, you would have to lose both pitot/static and GPS inputs to the G5 before the ADI X’ed out. Most installations will also have a GMU 11, and that may add additional robustness.

Skip

[hais]

28 minutes ago, PT20J said:

Garmin goes into some detail explaining this in the G3X Pilot’s Guide

Thanks! So I checked revision 6 of the supplement, that limitation is no longer there

 

[midlifeflyer]

14 hours ago, rbp said:

I went with a GPS/VLOC/COM GTN750xi and a GPS/COM GNC355

if I had to do it all over again, I would have spent a little extra money and gotten the GTN650 instead of the GNC355 because of the tighter integration with the 750, not for the second VLOC.

I have used the VOR receiver exactly zero times in the last year. I take that back -- I flew a VOR practice approach when I first got the panel, but I have never used it for actual navigation. I requested KABE VOR-A practice approach last week just for grins, but approach told me it was "no longer available," even though it had it it foreflight. It is however missing from airnav. Instead I flew the RNAV with a DA of 200', which was pretty *yawn*.

I think there are only two times we "need" VLOC in the real (as opposed to training/practice) world.

The obvious one is a GPS failure under IFR and a need to rely on MON routing.

The others are several situations in which either (a) the use of GPS requires more than rudimentary knowledge (where a lot of my recurrent training lives) or (b) using VOR is simply more efficient.  The number of them tend to be geographic-specific. The required knowledge and ability is pilot specific.  Efficiency is in the eye of the beholder. 

[Ragsf15e]

2 hours ago, midlifeflyer said:

I think there are only two times we "need" VLOC in the real (as opposed to training/practice) world.

The obvious one is a GPS failure under IFR and a need to rely on MON routing.

The others are several situations in which either (a) the use of GPS requires more than rudimentary knowledge (where a lot of my recurrent training lives) or (b) using VOR is simply more efficient.  The number of them tend to be geographic-specific. The required knowledge and ability is pilot specific.  Efficiency is in the eye of the beholder. 

There are a few big airports that still need ils.  I have no idea why, but I’m at KBFI (Boeing Field, Seattle) and there’s no gps approach to 32L, only the ILS.  Some places , that ils is still pretty essential.

[Ragsf15e]

13 hours ago, hais said:

Thanks! So I checked revision 6 of the supplement, that limitation is no longer there

 

One other thing (and @PT20J might be able to expound on this), the g5 and g3x have internal gps.  It does depend on how the setup is completed, but if the internal gps has a valid solution and your panel gps fails, it’s supposed to accept the best gps input.  So that should eliminate issues from a panel mount gps failure.  It still relies on pitot input for gps system outage/denial.

[EricJ]

11 minutes ago, Ragsf15e said:

There are a few big airports that still need ils.  I have no idea why, but I’m at KBFI (Boeing Field, Seattle) and there’s no gps approach to 32L, only the ILS.  Some places , that ils is still pretty essential.

They're doing a bunch of expensive remodels at our airport (KDVT), moving taxiways, etc., etc., in order to make enough room to meet the clearance specs for an ILS installation.   In other words, they're spending a lot of money in order to be able to install an ILS.   We already have RNAV approaches from both directions.   I think for high-traffic or critical areas they're taking GPS outage/security seriously (like the VOR MON) and want to have approaches available at enough airports in the event of the unavailability of GPS.

[Pinecone]

One advantage to having two VOR is, it makes the 30 day VOR check EASY.  I just tune both to the same VOR,and if the needles are on top of each other, good to go.