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Slide in TKM 8.33 Khz Nav Comm coming soon (KX155 replacement)!

Go on peter there must be a massive market for it. And why do u need a dealer sell them via the website.

Narco 810/1
Narco 12D
Narco AT150

Slide in replacements please

I am planning my 8.33Khz upgrade and I am considering all options from a GTN750/ new audio panel, second radio etc @ £ 18,000 installed to the bare minimum of junking one Nav Comm (I have two) and putting in a Comm only.

£ 18K is half the cost of my plane so apart from over capitalising it, I am still hoping that in 12-24 months there will be more competition from Dynon (or others) – they have a nice radio controlled by a huge glass cockpit – perhaps one day this will be legal in EASA land.

As part of my investigation I contacted TKM and asked them when their “slide in” Nav Comm was due out

The project is coming along very well! We have our display design submitted and will have prototypes in late January. From there we can finish up our testing and start the TSO approval process. We will start production on units for the Experimental market right away and start selling to the certified market once we have the TSO. We are hoping to have them ready by April for Sun n’ Fun in Florida, but if the approval process takes a little longer we will definitely have them ready for Osh Kosh in July. I will let you know if we need any pilots to test in Europe, I appreciate it!
Thank you,
Vic Casebolt
TKM Avionic

I emailed a follow up email on pricing and it will be “similar or a little more” than the present 25 Khz MX170C which is presently about £ 2,400.

TKM had some issues in the past as the integrated circuits we in IC sockets & used to shake loose on the logic boards. I have personally flown for 3 years with two TKM 170C’s and they have never missed a beat. I am thinking of waiting to see what emerges even though I will probably miss out on the 20% European rebate.

United Kingdom

The whole of Europe is waiting for a KX155 replacement……….if TKM can provide a reliable unit within the time frame they will make a killing.

The whole world has been waiting for a KX155 8.33 replacement

Quite a few thousand people would buy a KLN94 LPV replacement too

But these are just not fashion items!

Shoreham EGKA, United Kingdom

A_and_C wrote:

The whole of Europe is waiting for a KX155 replacement

I really don’t understand that others didn’t do this. Especially the sizing of the GNC / GTR is odd, smaller then KX-155 while larger then SL30/SL40.

A_and_C wrote:

if TKM can provide a reliable unit within the time frame

They announced this radio in early 2015, and according the post below has still to go in prototype / test phase. I really doubt they will be fully tested, and certified before April or July. All manufacturers seem to face delays on this.


It isn’t hard to do if you know RF design. The rest is easy. I looked at doing a KX165A/8.33 plug-compatible radio a few years ago, with various improvements of course e.g. doing it all using DSP and using a dot-matrix LED display instead of those unreliable EL panels.

It looked like a fun project but I had no stomach for the certification, which is not easy unless you are already a player and have the right certification agency connections.

And the homebuilt market is no help with a product which radiates stuff…

I think the lack of mfg interest in the KX155 radio market is that there are so many of them in the used market, and not expensive. I sold one mint-condition KX155A (not plug compatible with a 155) for €1500 on US Ebay. In the USA, Part 91, they don’t need the fancy paperwork to install stuff.

Also rewiring the rack from a 155 to a 155A or better still a 165A/8.33 costs about 500 quid in labour, which is not bad.

Shoreham EGKA, United Kingdom

Peter wrote:

I think the lack of mfg interest in the KX155 radio market is that there are so many of them in the used market, and not expensive.

This was about 8,33 replacements for KX-155. It is strange that they aren’t direct replacements for those, or other manufacturers doing the the same size.

With a Garmin you always need to redo the radio stack, as it smaller then KX-165 KX-155 yet taller then SL-30/SL-40. These are the most common non 8,33 kHz radios.


There is no 8.33 market in the USA, which limits the interest from the obvious players.

Shoreham EGKA, United Kingdom

There is undoubtedly a market for replacing the KX155 with a slide in replacement however unless they are very quick getting the unit onto the certified market and for some operator like me they have already missed the bus.

The real prize for the radio manufacturers is the commercial operators who are going to make multiple buys and are likely to be the easiest to support. The problem for TKM is that most of the well financed commercial operators will already have made their plans because they know the installation providers are going to be overloaded towards the end of 2017 and can’t afford to have aircraft grounded for the chance of saving IRO £2k per radio.

I like Jesse can’t see why no radio manufacturer did not grab the KX155 slide in replacement market with both hands ( like Trig did with the transponder market ). May be they all listened to the rumours from each other and decided not to get into a very competitive market.

I suspect that most of the commercial operators will go for the Garmin GNC255 ( as I have ) due to availability and proven customer support while the penny pinching amongst the private owners are trying to find ways to keep the NAV side of their old radios while fitting a single 8.33 Com.

I forgot to mention that I also contacted Trig and their NavComm is nowhere near release, they could not even tell me the size of the prospective TX56/TX57 which they told me last year was going to be released in 2017

What I don’t understand is why nobody makes a small NavComm and then provides adapter units which convert into different racks. One radio could then fit lots of racks.

Later on when people decided to “properly” upgrade their Aircraft………….for example to upgrade to a GPS RNav unit like the GTN650……….. then they could then re-use the smaller Nav Comm as box 2 by using the smaller dedicated tray. This would be handy as space is often needed for the GTN’s or similar.

United Kingdom
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