New Aircraft, in need of avionics advice.

Me and my dad just bought a 1975 Cessna 182P. It does not have Mode C or adsb and it still has the original cessna radios which we want to replace although they do work.

We plan to use the 182 for cross country trips as well as to build time towards an instrument rating. I think a GNX375 makes sense for adsb and ifr but I need some advice on the radio's and mode C transponder. Any suggestions?

 

With the GNX375 you'd have no need for a mode C transponder (it's a Mode S w/ES to cover all your transponder/ADSB needs). You could then add a GNC255 for a nav/com and a GTR225 for a second com and call it a day unless you wanted some extra redundancy. What is your planned usage profile for the plane?

 

Nice, I guess that's where I was confused. Just to be sure: you're saying Mode S fulfills the requirement of Mode C, meaning I can fly into class B airspace prior to 01/01/2020 with a mode S instead of a C?

Also, what is the advantage of the GTR225 vs a GTR200?

We'll be making frequent 400 mile vfr cross country trips and also working towards instrument rating.

 

GTR200 is not TSO’ed, so it’s only for experimental aircraft.

Mode S also give mode C (altitude output).

 

I see. That explains it. Thank you.

Are there any other reputable brands (radios) aside from Garmin? If so what is the trade off?

 

Trig, PSEngineering, TKM (depending on your definition of "reputable"). There's also Dynon, but the radio is part of a system rather than standalone. Similarly, the IFD440 is bundled with GPS.

 

Something to consider
Www.ps-Engineering.com/PAR200B.shtml

 

This is great advice. GNX375, GNC255A. Also consider a new audio panel like the PS Engineering 450B. Replacing radios means retiring the audio panel, might as well put a new stereo unit with Bluetooth over wiring the old one back up.

 

Another consideration is just go with the 375 and 2 Garmin 225’s (Comm only). You lose the VOR/ILS capability, but after installing the 375 GPS/ADSB, you never use VOR‘s anyway. The 225 is much cheaper than the 255.


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I would want ground-based nav and approach capability as a backup to GPS. At equipped airports, you will normally be expected to fly the ILS, and it often has lower mins than the corresponding GPS approach. I agree you will rarely if ever use VOR nav except in some sort of emergency.

 

I don’t fault wanting ground based navigation, but most ILS approaches have an LPV with the same mínimums or maybe 50’ higher. They often will assign the ILS if they have one, but never refuse the RNAV if you request it. Also, many airports with ILS will have an LPV going both ways, so if the wind doesn’t favor the ILS runway, you can get much lower with the LPV than circling minimums on the ILS or the LOC back course (I’ve personally never done one of these).

 

I would probably put in a Garmin 650 or 750.. Which will give a new Radio, VOR, ILS, and GPS system, you can keep one of your original radio’s or upgrade it. Then of course an appropriate Transponder for the ADS-B. Not sure which one that is.

Brian
CFIIG/ASEL

 

Some installers will happily install a GTR200 in a certified aircraft. Not all installers agree it's legal, but some do and will sign it off as a minor alteration.

 

The "appropriate transponder" would be the GTX345 transponder. The problem with your suggestion is that it's a good deal more expensive than a GNX375 (GPS+transponder). A GTN650+GTX345 combo has a list price of $17000. A GNX375 has a list price of $8000.

 

I’m a professional pilot for a living. Most LPVs have the same mins as the ILS. At work, we almost always fly the LPV over the ILS because it much less button pushing on the setup and missed approach.

In my 310 I fly for fun, I have a Foreflight with the Garmin 345 and GDL51 both as backup Nav sources. I have a GTN650 and never use the ground based Nav feature. If there’s and ILS, then it almost has an LPV as well.

I’m never “expected” to fly the ILS even if it’s on the ATIS. If I want the RNAV approach in lieu of the ILS, I just tell the controller I’d like the RNAV. I’ve never been denied an RNAV over the ILS. I think the only airports that don’t have LPV approaches with an existing ILS are military bases. Almost every airport has an RNAV (LPV, LNAV, LNAV/VNAV) approach.

If I could go back and redo my avionics, I probably would have done the 375 with 2 Garmin 225 Comm radios. I would have saved about $4k dollars.

As the above post says, if you go with the GTN650, then you should go with the GTX345. They play well together and it’s ADSB In/out vs ADSB Out only on the GTX335.

The 375 is IN/Out and also has the built in Bluetooth saving you another $1100 by not needed the Flightstream 210.


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And the GNX375 is a perfectly acceptable solution, but he will still have the 45 year old Navcoms. If they are working that is fine.

Brian

 

There are still radial clearances (OBS works for that) and also some airports with only an ILS or vastly different ILS vs GPS mins. Also, VOR and LOC approaches technically require a NAV radio to back them up, and they are preferred at some airports (to the point that some controllers basically force you on them). I wouldn't dump all radio NAV capability yet, but I'm perfectly happy having just one.