Aft Radio Rack

[bjoness]

Looking at installing ADS-B boxes in both a 170A and an early 172 (essentially same as 170B). Has anyone installed avionics aft of the baggage compartment in the tail cone? What type of avionics mount did you use and/or make? Any pictures?

[Bruce Fenstermacher]

No pictures however my A model has a rack made of aluminum angle that spans the fuselage just aft of the baggage compartment. it currently has the power supply for the strobe lights mounted to it. But over the years it has also had radio power supplies and even a wing leveler servo mounted to it.

[johneeb]

No detail about shape however here is a photo of one of the racks in my airplane. I have subsequent to this photo added another rack opposite this one for additional equipment.

170 progress 2003-11-01 009.jpg

[voorheesh]

My understanding is that the 978 UAT transmitter (weighs less than 1 pound) has to be installed in the aft part of the aircraft and the antennae on the bottom. There is an optional top antennae that either makes us more visible to airliners with the 1090 ES or visa versa. The model I am looking at is compatible with my KT76A King transponder but there is a $300 modification required for the Mode C (supposedly a replacement wire to the UAT). This means that your transponder is still your panel mount and it connects up with the ADS-B unit installed in the rear of the airplane. Install now and the unit is fully functional anywhere ADS-B is active in the NAS.

I was talking with a local avionics shop owner today and he advises that we should not wait for prices to go down because there is going to be a rush on this equipment as January 2020 approaches. He says it has to be installed and tested by a certified avionics shop and there is an FAA test done after installation to make sure the equipment is functioning properly. If you consider the number of qualified shops and the number of general aviation airplanes with transponders, they won't all get done by 2020, even if we start today. Ok, maybe he is trying to drum up business. 5 years, 3 months, maybe not a big deal yet?

After January 2020, you won't be able to fly in airspace that currently requires a Mode C transponder unless you have ADS-B out. Many of us don't need to fly in that airspace and some don't even use transponders today. I am told our Mode C/A or Mode S transponders will be useless after 2020 without the ADS-B mod. In my case, I need access to airports within the San Francisco 30 mile Mode C ring so I am getting in line (also like to get VFR traffic advisories and ADS-B will be required for those too). I believe it can be done between $3000 and $5000 including the link to IPad for FIS-B and TIS-B (ADS-B In). I would recommend looking into this with your local avionics guy and please don't take what I have written here as gospel. It was just an informative conversation at airport today and coincidental with this thread.