New NAV/COM help.

[AlphaMike]

This is my current panel. I just bought this plane last March and the previous owner did a really good job upgrading the panel, but he neglected the Nav / Com 2. It’s an old kx 170 (not a 170a or 17b). The nav side of the radio isn’t hooked to anything and the com side is almost useless (about 4-mile range if it works at all). Everything is connected to the GTN750. At my next annual I plan to address this. I would like to connect the backup CDI to a Nav2 and get a true Com 2 radio. My next annual isn’t due till Feb 2021 so I’ve got some time. I was thinking of getting a GNC 255 but wow are they expensive for what you are getting! Any suggestions? Thanks!

 

[Ryan Klems]

I'd make sure your KX-170 was modified to meet the new frequency tolerances that went in to effect in 1997, otherwise that's an illegal radio if used to transmit. https://www.aopa.org/news-and-media/all-news/1996/october/pilot/tuning-a-new-com

As far as a replacement goes, there aren't a lot of lot of new nav/coms on the market these days. Trig has been saying they are coming to market with the TX56 for a while, but it's been delayed. A used SL30 is a nice radio, but those are getting long in the tooth and who knows how much longer repairs will be available. The GNC255 is probably your best choice right now. You could slide in a TKM radio and get digital flip flop, and should be able to hook it up to your CDI, but I wouldn't exactly call that a modern radio and it's not much less than the GNC, though install would be less.

FYI, it looks like your GI-106 CDI is connected to the GTN? That's not approved per the G5 STC install manual, you aren't supposed to have an external CDI for any navigator interfaced to the G5.

 

[CRQFlier]

You're basically at the same spot I am - except you already have a sweet panel whereas I'm just trying to plan thoughtfully. Seems like the 255 is it for vhf nav2.

Sent from my SM-G960U1 using Tapatalk

 

[asicer]

One possible route (not necessarily the best route) is a VAL INS 429 for nav2 and Trig TY96A for com2. Selling your existing GI106 might be enough to offset the cost of the TY96A.

 

[AlphaMike]

Thanks for the comments. I did not know about the CDI not approved with the G5.. Good info and another reason for the NAV2. Does anyone know real world ballpark pricing for a 255?

 

[NordicDave]

Thanks for the comments. I did not know about the CDI not approved with the G5.. Good info and another reason for the NAV2. Does anyone know real world ballpark pricing for a 255?

$3800 ish. Sometimes there are rebates. GNC-255A is a nice radio with ILS/GS/VOR

 

[bradg33]

Think long and hard about why do you want a second NAV radio in this day and age, and whether it's worth the $$ and hassle. When I re-did my panel, I concluded that a WAAS navigator and a single NAV (w/ glideslope) was more than sufficient for my needs. So rather than spend a fortune on a nav/com and indicator, I bought a stand-alone Garmin GTR comm radio. Works fantastic, and way less expensive than a full-blown NAV/COM.

 

[AlphaMike]

Bradg33. I would agree with you but with the setup I have if my GTN750 dies I’m screwed. No nave or com. That’s my fear. And of course that would happen when I’m in hard IMC.

 

[NordicDave]

Bradg33. I would agree with you but with the setup I have if my GTN750 dies I’m screwed. No nave or com. That’s my fear. And of course that would happen when I’m in hard IMC.

Took the same approach in my plane. The 2nd nav/comm with ILS & GS is terrific to have. Plus I have a couple of tricky departures that require looking at 2 radials, and it just makes that easier too.

For another $1200 the Nav/Comm 255A was worth it over the just the Comm 225A.

 

[bradg33]

Bradg33. I would agree with you but with the setup I have if my GTN750 dies I’m screwed. No nave or com. That’s my fear. And of course that would happen when I’m in hard IMC.

Definitely have a second COM, I just don't necessarily think a second NAV is necessary. I hear your dilemma, but the likelihood of the radio giving up the ghost at exactly the wrong time, short of a full electrical failure, is pretty low. And foreflight on an iPad is probably nearly as useful as a second NAV radio, other than the glideslope.

 

[asicer]

For another $1200 the Nav/Comm 255A was worth it over the just the Comm 225A.

Did you swap digits? Are you sure the difference is $1200 and not $2100?

 

[AlphaMike]

Bradg33. Take a look at my setup. The GTN750 is my everything. It’s my audio pannel, it’s where I set my transponder it’s my gps and my vhf. If the screen goes out I’m pretty much screwed. I love the setup but if something fails I’m done.

 

[asicer]

Bradg33. Take a look at my setup. The GTN750 is my everything. It’s my audio pannel, it’s where I set my transponder it’s my gps and my vhf. If the screen goes out I’m pretty much screwed. I love the setup but if something fails I’m done.

Sell the GI-106 for $1500. Buy a VAL INS429 for $2000. Net cost in parts is $500.

 

[Ryan Klems]

Sell the GI-106 for $1500. Buy a VAL INS429 for $2000. Net cost in parts is $500.

But then he’s still got an ancient 360 channel com that may or may not be legal to transmit on depending on if it’s been modified or not... but even if it has, he can’t tune all the freq’s. So he really should get a new COM too, and by the time he does both it’s about a wash with a GNC255.

 

[bradg33]

Bradg33. Take a look at my setup. The GTN750 is my everything. It’s my audio pannel, it’s where I set my transponder it’s my gps and my vhf. If the screen goes out I’m pretty much screwed. I love the setup but if something fails I’m done.

Well, in that case a second NAV/COM isn't gonna do much for you anyway. I don't know enough about the workings of the 750, but can you even activate Com2 if the 750 dies and you lose access to the audio panel? Does it somehow fail over to Com2?

In any event, IMHO, you're planning for a pretty far out contingency - the 750 itself dying (not a full electrical failure) in a hard IFR situation where you'd need to shoot an approach with enough precision that Foreflight wouldn't get the job done. Frankly, a full electrical failure is probably more likely. Depends on your kind of flying, but with the flying I'm doing ("gentlemen's IFR," I don't have any business going to 200 and a half), I'd be OK with the setup.

But it's a pretty personal choice, based on a combination of budget, desire and risk-tolerance.

 

[asicer]

But then he’s still got an ancient 360 channel com that may or may not be legal to transmit on depending on if it’s been modified or not... but even if it has, he can’t tune all the freq’s. So he really should get a new COM too, and by the time he does both it’s about a wash with a GNC255.

Not exactly. Going the INS429 route, he's recovering money from selling the GI-106. Going the GNC255 route, he'll want to keep the GI-106 or lose GS indication. Plus, there are several options for COM2 besides a GTR225 that are almost as good.

 

[CRQFlier]

One of the comments on Spruce is that the VAL is not TSO any longer. So for an ILS within regs it doesn't seem to be a solution. But for real world back up if the 750 goes out?

Sent from my SM-G960U1 using Tapatalk

 

[asicer]

One of the comments on Spruce is that the VAL is not TSO any longer. So for an ILS within regs it doesn't seem to be a solution.

Although VAL claims it was built to TSO standards, I don't think the INS429 was ever TSO certified. However, you're inviting a rant by @weirdjim on how TSO is not required by regs if you try to claim otherwise

I believe @Timbeck2 installed a VAL in his plane and can probably weigh in on the experience.

 

[AlphaMike]

With the GTN750 if it fails com 2 becomes active. If I flip on the master switch com 2 is active until the 750 boots up.

 

[unsafervguy]

Although VAL claims it was built to TSO standards, I don't think the INS429 was ever TSO certified. However, you're inviting a rant by @weirdjim on how TSO is not required by regs if you try to claim otherwise

I believe @Timbeck2 installed a VAL in his plane and can probably weigh in on the experience.

its not a rant when it is 100% true, its called education. val radios are totally legal to install and use in a pat 91 aircraft.

 

[asicer]

its not a rant when it is 100% true, its called education. val radios are totally legal to install and use in a pat 91 aircraft.

Well, education does come in both hard and soft varieties. If not a rant, then probably not the latter.

But I do not disagree that VAL radios are totally legal to install and use in Part 91 aircraft.

 

[NordicDave]

Did you swap digits? Are you sure the difference is $1200 and not $2100?

GNC-255A $3859
https://www.gulfcoastavionics.com/products/3825-gnc-255a.aspx

GTR-225A $2636.00 (edited from GNC to GTR)
https://www.aircraftspruce.com/catalog/avpages/garmingtr225ab.php

Difference is $1223

everybody’s safety margin and comfort level is different. For me I would prefer to have a second completely independent NAV/com set up from the Gps as a back up.

 

[asicer]

GNC-225A $2636.00
https://www.aircraftspruce.com/catalog/avpages/garmingtr225ab.php

First off, it's GTR and not GNC. Secondly, the 225A is for European operations (8.33Khz spacing). The GTR-225 (no bloody A or B) for 25khz spacing North America operation is $1825:
https://www.aircraftspruce.com/catalog/avpages/garmingtr225.php

Difference is $2034

 

[Doug Reid]

Aside from the fact a KX170b has mechanical frequency display, which is great if it works properly, the KX170b and KX175b radios are very well built and have excellent audio, plus they are 720 channel radios and are legal. Get one and slide it in your existing tray.

You can find a good indicator on ebay for a couple hundred dollars. No rewiring is necessary unless your nav pigtail is missing that goes to the nav indicator.

 

[NordicDave]

First off, it's GTR and not GNC. Secondly, the 225A is for European operations (8.33Khz spacing). The GTR-225 (no bloody A or B) for 25khz spacing North America operation is $1825:
https://www.aircraftspruce.com/catalog/avpages/garmingtr225.php

Difference is $2034

I did miss typed GNC instead of GTR for the 225. The 225 is offered in 3 variations.

The GTR-225A does operate with US frequency separation, and not Euro specific. The straight 225 model is $720 difference shopping Sarasota.

$2549 https://sarasotaavionics.com/avionics/gtr225a
$1829 https://sarasotaavionics.com/avionics/gtr225

Even if the difference is about $2000 versus 1200 and change I’d still have a NAV/Comm radio over just a Comm radio.

 

[guzziguy]

This is my current panel. I just bought this plane last March and the previous owner did a really good job upgrading the panel, but he neglected the Nav / Com 2.

Ha...
No, he didn't NEGLECT anything. He just ran out of money....

 

[Bathman]

Just get a replacement KX-170b. You can pick up pretty clean ones for a few hundred dollars then just slide it. If that solves you COM problem then great. Personally I would also get it wired in as your NAV2 back up.

The KX170b is a great radios and it wouldn't be silly money.

 

[5QK]

Bradg33. I would agree with you but with the setup I have if my GTN750 dies I’m screwed. No nave or com. That’s my fear. And of course that would happen when I’m in hard IMC.

The same could be said for your engine

 

[Piper18O]

Think long and hard about why do you want a second NAV radio in this day and age, and whether it's worth the $$ and hassle. When I re-did my panel, I concluded that a WAAS navigator and a single NAV (w/ glideslope) was more than sufficient for my needs. So rather than spend a fortune on a nav/com and indicator, I bought a stand-alone Garmin GTR comm radio. Works fantastic, and way less expensive than a full-blown NAV/COM.

You could get a 170b and replace your 170, and also get a nav head, but my question is would you rather fly by that old antiquated technology, or by your tablet with Foreflight, Fltplan go, or Avare, etc.? I had an alternator failure once on a flight. To conserve battery, I just shut the master switch off, flew following my tablet, and had my backup handheld radio for communication. That scenario is probably just as likely as only your first nav com going out. In other words, there is a pretty good chance that if you lose one nav com, you are just as likely to lose 2 nav coms. Technology is amazing today. It is far more versatile and a lot cheaper than many other options. Also, more than likely, your limited range on your 170 is due to antennae, coax, or other wiring issues anyway, and if you open that can of worms, you may be getting more than you bargained for, at least cost wise. What I am saying is, if you have money to burn, spend it. Otherwise a used replacement 170B slide in is probably a good compromise.

Doug Reid > "Aside from the fact a KX170b has mechanical frequency display, which is great if it works properly, the KX170b and KX175b radios are very well built and have excellent audio, plus they are 720 channel radios and are legal. Get one and slide it in your existing tray. You can find a good indicator on ebay for a couple hundred dollars. No rewiring is necessary unless your nav pigtail is missing that goes to the nav indicator." This is pretty solid advice.

Ditto for Bathman > "Just get a replacement KX-170b. You can pick up pretty clean ones for a few hundred dollars then just slide it. If that solves you COM problem then great. Personally I would also get it wired in as your NAV2 back up. The KX170b is a great radios and it wouldn't be silly money."

 

[flyingron]

I'd make sure your KX-170 was modified to meet the new frequency tolerances that went in to effect in 1997, otherwise that's an illegal radio if used to transmit. https://www.aopa.org/news-and-media/all-news/1996/october/pilot/tuning-a-new-com

There's no "modification" that can be done. The KX-170 is ILLEGAL to transmit with as it does not meet the frequency tolerances mentioned above and can't be made legal. Same for the 170A. As others point out, you could replace it with a 170B, but you'd still have n ancient clunky radio. that won't receive all the frequencies (it's only a 720 channel radio).

 

[asicer]

...you could replace it with a 170B, but you'd still have an ancient clunky radio that won't receive all the frequencies (it's only a 720 channel radio).

Slightly OT but just out of curiosity, which ground stations operate in the 136.000-136.975 range?

 

[flyingron]

Slightly OT but just out of curiosity, which ground stations operate in the 136.000-136.975 range?

The frequencies are mostly split between AWOS and future UNICOM use and ATC. I have been assigned one in this range by some ATC facilities.

 

[asicer]

The frequencies are mostly split between AWOS and future UNICOM use and ATC. I have been assigned one in this range by some ATC facilities.

Also to help answer my own question, I see only two listed in the d-CS: RNG info at KFTK (136.075) and apron tow coordinator at CYYZ (136.525).

 

[Ryan Klems]

There's no "modification" that can be done. The KX-170 is ILLEGAL to transmit with as it does not meet the frequency tolerances mentioned above and can't be made legal. Same for the 170A. As others point out, you could replace it with a 170B, but you'd still have n ancient clunky radio. that won't receive all the frequencies (it's only a 720 channel radio).

There certainly appears to have been at the time, 24 years later I’m sure it’s long gone, but king appears to have offered a mod at the time. From the article “ Note: King's KX 170, KX 170A, KX 175, KX 175A, and KY 195 can be upgraded to meet the new frequency tolerance, but they will remain 360-channel radios. Cost of the upgrade is $322 for parts plus 3 to 4 hours of labor”

 

[Jim Carpenter]

I don't believe anyone mentioned TKM radios, they make a slide-in replacement for the KX-170 series (as well as for Cessna, Narco, etc.)
And, very nice looking panel, by the way!