Do I need to keep my VHF Nav?

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dstates
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Do I need to keep my VHF Nav?

Post by dstates »

Fellow 170 fans,

I have a KX-170B nav/com radio and a King indicator in my 170, but the nav function is inop due to a faulty connection back to the antenna (per the previous owner). I'm considering a major avionics upgrade by adding a Garmin G5 HSI and GNX 375 (GPS with integral transponder). I'm instrument rated, but not current (yet). Seeing that my current nav indicator is inop and doesn't have a glideslope I'm planning on removing it altogether to have room for the HSI.

That radio isn't great for instrument flying either, so I will probably replace that next year (one piece at a time). But it is much cheaper to just replace a com radio and not a nav/com.

All this to say, can anyone share why I might need to have a VHF nav receiver any more?

Doug
N1235D - 1951 170A - SN: 20118
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brian.olson
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Re: Do I need to keep my VHF Nav?

Post by brian.olson »

Doug:

There will be smarter folks than I responding, but I'll give you my two-cents' on the matter. I got my IFR ticket in July, and subsequently installed a G5 HSI and a GTN650 into my 170 in August. I've used the new equipment a fair amount since that time. Note that I got rid of the single nav/comm + ILS head and replaced it with the G5 HSI + 650 (GPS, Nav, Comm), so I did not necessarily add redundancy.

In reading the minimum equipment list for IFR it states (for radios) "two way and navigational equipment
appropriate for the ground facilities to be used". Essentially if you had zero intention of navigating via ground-based sites (VOR, ILS) or "communicating" with them (listen in on VOR), and ONLY fly via GPS common sense would seem to indicate that Nav is not required. I could be wrong here (any instructors out there?).

A couple points, though, where I have needed Nav:

1. You need nav to fly a VOR, ILS or Localizer approach. ILS will sometimes have a lower minimum than a RNAV approach (not always), and not all approaches can leverage the lower minimums from LPV approaches. You will only be able to fly a RNAV approach (but ... while we train to fly to minimums, not sure I want to take my 170 in that level of IFR where the difference is necessary/important);
2. There have been three instances when I have been in the air since August where GPS was intermittently not available. All on good-weather days, all with US-Defense NOTAMs in place for testing purposes. I was not flying IFR, but it scared the crap out of me seeing LOI in yellow letters show up on the equipment. Had this been actual conditions I would have needed to fall back to VOR/airway navigation or send up a flare to ATC and follow Foreflight's magenta line;
3. If you file IFR and weather minimums dictate an alternate airport, airports with just RNAV approaches cannot qualify as an alternate. Again, this may not be applicable, but the minimums for that are actually fairly high. You may be in a legal bind from time to time as to when you fly IFR, if that is your intention.

Just some thoughts as you go through your decision-making process and not trying to influence you in any other way, other than to encourage you to put in the new Garmin equip. I love the new Garmin equipment, btw, and if you learned to fly IFR using limited instrumentation it feels like cheating. Couple this with Foreflight in the cockpit and there is a level of sophistication and back-up that is second-to-none.

Good luck!

Brian
Brian
1950 170A
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Re: Do I need to keep my VHF Nav?

Post by GAHorn »

I believe the best answer will be from your FAA-FSDO and your avionics shop, and that their answer will be that in order to file/fly IFR you will need VHF Nav even if you plan to utilize GPS.
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hilltop170
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Re: Do I need to keep my VHF Nav?

Post by hilltop170 »

Doug-
I would not eliminate the VHF nav if any IFR is planned. If you will be flying VFR only, go ahead and take it out. I agree the only time I use VHF nav these days is when ILS or VOR approaches are co-located with the GPS approach I am using or the rare occasion when I actually have to shoot an ILS or VOR approach.

Another option if you want new equipment is to take out the old dinosaur VHF equipment and get a GTN650 or something new that has VHF nav built-in with the GPS instead of the GTX375.

I removed my old KX170B radio and replaced it with a used GNS430W that was sent back to Garmin for rebuild which has VHF nav and added a Garmin 225 com-only for back-up com. I have plenty of other GPS back-up.

Good luck!
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
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dstates
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Re: Do I need to keep my VHF Nav?

Post by dstates »

Thanks for the replies. Like I said, I’m not current so I didn’t remember the alternate airport requirements. I did some reading and confirmed that you can file using a GPS approach at either the destination airport or the alternate, but not both.

So. I guess I need to keep a Nav/Com in the plane as I do want to get back into the IFR system again. I’ll have to see if my budget can be adjusted to add a GTN650 and G5 HSI.

Brian Olson, can you share a picture or two of your GTN 650 and G5 installation?

Thanks,
Doug
N1235D - 1951 170A - SN: 20118
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brian.olson
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Re: Do I need to keep my VHF Nav?

Post by brian.olson »

Doug:

While this isn't the "best" photo, it does show the placement of the new equipment.
62C Updated Panel copy.jpg
Here's a second photo that my wife took just after we broke through the bottom of the clouds while on the RNAV 31 approach at our home airport. It does a better job of showing the equipment actually in action.
RNAV31.jpg
.

Also note that the avionics shop had to install a small audio panel into the mix as well, as the GTN650 wasn't able to port audio for both comm and nav directly into the headset/speaker. My KX125 was able to do that, for some strange reason, and prior to the upgrade I did not have an audio panel per se. That added a few dollars but the end-product works great.

Let me know if you have any further questions -
Brian
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dstates
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Re: Do I need to keep my VHF Nav?

Post by dstates »

Thanks, Brian, that does help. I don’t currently have an artificial horizon so I plan on dual G5’s. I also have a 4 place intercom so hopefully that will work fine with the GTN650. I didn’t think about indicators for the marker beacon. Is that required or will the GTN announce when you are over the markers?

Doug
N1235D - 1951 170A - SN: 20118
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Re: Do I need to keep my VHF Nav?

Post by brian.olson »

Doug - the marker beacon indicators and the mini switches in the middle of the panel are inop - they were installed with a marker beacon receiver many, many years ago (previous owners well down the chain) that was removed long ago and the switches appear to have been some type of rudimentary audio panel. At some point I'll have a new overlay fabricated, and should probably label them "inop" to avoid any confusion from an inspector in the meantime. No need for a DME or marker beacons with the GPS.

If the funds would have allowed I would have preferred to go the dual G5 route but I had to draw the line at some point, and the HSI provided the greater value and utility to me. If things go down the tank I can quickly switch it over to the AI mode with a couple of button presses.
Brian
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Re: Do I need to keep my VHF Nav?

Post by wabuchanan »

Brian,

What made you opt for the Garmin 650, vs the 355 with the integrated nav/com radio?

I'm not currently IFR rated, and am researching these for my 170A to learn in, and so am trying to figure out pros/cons, and the differences.

Bill
1950 170A N5776C SN:19730
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Re: Do I need to keep my VHF Nav?

Post by cessna170bdriver »

wabuchanan wrote:Brian,

What made you opt for the Garmin 650, vs the 355 with the integrated nav/com radio?

I'm not currently IFR rated, and am researching these for my 170A to learn in, and so am trying to figure out pros/cons, and the differences.

Bill
The 355 is a GPS/Com; no VOR/ILS receiver. The 650 is a GPS/Nav/Com, a more modern version of the 430W.
Miles

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Re: Do I need to keep my VHF Nav?

Post by brian.olson »

Bill - as Miles pointed out, the 650 included "everything" (GPS, Nav, Comm), and it allowed me to replace my existing nav/comm, my DG and my VOR/ILS head. Panel space was at a premium. In hindsight I suppose I could have kept the low-profile KX-125 radio and just moved it, but the 650 allows you to monitor the standby radio frequency so I really didn't need it.
Brian
1950 170A
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Re: Do I need to keep my VHF Nav?

Post by wabuchanan »

Miles and Brian,

Thanks for the clarifications.

Brian, I am going to PM you.
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Tom Brookover
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Re: Do I need to keep my VHF Nav?

Post by Tom Brookover »

Doug and Brian (and all),

I am facing radio decisions similar to you both. I fly VFR, use Foreflight for SA, and am wanting to learn to fly IFR in the next year or two in my 170B. In the meantime, I've decided to upgrade to ADS-B and am considering going with Stratus in and out (only) for now with the likelihood of upgrading my 30-yr old KX155 to the GTN650 or similar when it breaks. Another option would be to install two Garmin units to handle ADS-B, GPS/NAV/COM - GNX355 and GTR255 as one example. The expense of latter probably puts it out of my reach for the near future.

Did you give much thought to going with Garmin-only radios vs a mix of Garmin and Stratus? I understand the Garmin packages allow for weather and traffic on the (Garmin) screen and with the Stratus, that is not available. Any other downside in using the Stratus in combination with the Garmin units? Any regrets? I would appreciate any and all thoughts on the options. I am hoping to install ADS-B now but preserve the ability to end up with a well-integrated panel some day.

Thanks, Tom
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dstates
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Re: Do I need to keep my VHF Nav?

Post by dstates »

Tom.

I’m now leaning toward Dual G5’s and a GTN 650. That will give me an attitude indicator that I don’t currently have and a great HSI. One thing about the G5 HSI is that you can’t have two nav sources (ex. GNX 375 for GPS and GTR 255). With a GTN 650 or GNS 430W you can send both VHF and GPS info to the G5 HSI.

As far as ADS-B, I haven’t decided yet. I’d love to put in a GTX 345 to get In and Out, but I’m not sure my budget can handle it. I’m considering doing a cheaper solution like uAvionix or GDL82 and upgrading to something with in and out later.

Doug
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Re: Do I need to keep my VHF Nav?

Post by Tom Brookover »

Thanks Doug. The G5s and GTN650 sound like they'd be a great combo.

I'm not sure I understand all the differences between ADS-B options. I am hearing that non-Garmin ADS-B options aren't capable of providing weather and traffic to the GTN650 (or similar Garmin products), but can provide that data to an iPad. A bigger deal though may be traffic callouts. My understanding is that ADS-Bs other than Garmins are not capable of providing audible callout warnings for conflicting traffic. Not sure if that's true or not, but to me those callouts could be a pretty useful safety feature.
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