Make up my mind, used navcom, new navcom or gnc355

[McMooney]

I originall had an mx170b as navcom 2 in birdy but during maintenance an A&P lost the locking screw and pall causing the radio to slide in and out of the stack freely.

I replaced the locking pall and next avionics installation, they lost it again, sigh.  unfortunately this caused an issue with the radio causing it to be intermittent.

replaced with a kx170b i had laying around, all good.

well i want my fliip flop back, i know it's minor but it really annoys me.

so, i can buy a working mx170c for approx 2500$, slide it in, done.

or

garmin gnc255a with 8.33 which i will need 10 years down the road( i plan on hopping across the pond when i retire )  $$$  due to installation but as i now have g5s and a spare md200 indicator no other parts are needed to purchase  

or

i can get a second gpss comm in a gnc355, $$$$, probably about the same install cost as the gnc255a except they want to put ANOTHER gpss wart on my plane, i already have 2, pretty soon the lane will look like it has measles

 

 

 

 

Edited January 20 by McMooney

[Rwsavory]

I would buy a working mx170c and call it good. I have looked at getting a newer navcom2 to replace my KX155, and there's little added benefit to spending the extra money. 

[PeteMc]

Who knows what Regs will change in 10 years and what radio improvement there will be.  We may have Digital Transmissions by then.  Unlikely, but not out of the realm of possibilities. 

Second GPS is great, but if you just replace the radio then you can buy the latest and greatest when it's time to cross the pond. 

[Utah20Gflyer]

I had a very similar situation.  I purchased my plane with a mx170b and a king 170b but they both ended up being bad.  I replaced the mx170b with a 355 gps/com and the king 170b with a 175b that worked.  Later I replaced the 175b with a gnc 255 nav/com.  The mx170b/c doesn’t have a good reputation for longevity so I wouldn’t personally do another one.  If you have a WAAS gps currently that you think will go another 10 years I would do the 255.  If you think you’ll need to replace one of the GPS in the next decade I’d do the 355.   The Mx 170b doesn’t have a glideslope receiver or frequency database so it is not really equivalent to the 255.  The 255 is also much smaller which is nice since Mooneys, especially older ones, don’t have much panel space.  
 

I did send the mx170b in to be repaired first but was told it was not repairable.   I would have been willing to pay 800 to keep the mx170b running but thought 2500 was too much to put into an old radio.