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I was getting my Bi-Annual Transponder check at a local Avionics shop who has never done this on an Icon, They said there was no access to the encoder, so they needed to hook up to the pitto to do the test thru pitto, similar to an IFR test,,,In doing so they could not get a clear reading and said there must be a leak in my system?...I then flew the plane to have ATC verify my speed, altitude, location and all checked out perfect....I spoke to Icon and got no clarification,...

Anyone experience this issue?

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That repair station has no idea what they are doing. Find another. The encoder is in the transponder control head. The test for a non-IFR aircraft is very simple and 20 year old test box can test it remotely from inside your hangar or on the ramp. We did these checks on the production line and I have the same transponder on my Pitts that I just had done by a local repair station. It takes about 10 min tops. For what it’s worth the value of the barometric pressure altitude the encoder is measuring and transmitting is on the display at all times at the 100ft increment and is available in the setup menu down to the 1ft increment. If you need help I can point you to those menus. Bottom line is that repair station doesn't know what they are doing. In other words if they went to trig's website to see how to look up this information it wouldn't be a question back to you. Its amazing how many mechanics and repair stations don't use OEM data to perform inspections. It one of the most important aspects of being a mechanic or repair station follow the manufacturers provided data.

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Hi Bret, I can't agree more with you.....There was 3 of them and they were all confused...Excuse my ignorance, do you need to take off front dash to get to the encoder transponder control head?.... If you know our Trig Model # off top of your head , can you send me it and I will look it up....thanks!

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it’s a Trig Avionics TT22. All the manuals are on this page https://www.trig-avionics.com/produc...t-transponder/

The one static line for the encoder is tee’d off the main static line that comes from the tail ports. The MSC (for AoA calculation and FDR airspeed data), the altimeter and the A/S indicator all tee’d off that line. The altimeter and a/s static line is accessible by removing the instrument hood on the pilot side just pull up gently in the aft edge they are rubber ball sockets.

That all said there is no reason to do any of that because you don’t need to comply with 14 CFR 91.411 as you are not certifying an IFR system. You only need to comply with 14 CFR 91.413 a transponder check in accordance with 14 CFR 43 Appendix F there is no mention of an encoder or static check. The only mention of altitude is that it’s reading in the correct format on the test box. Read for yourself here:

https://www.ecfr.gov/current/title-1...to%20Part%2043

if you are getting an IFR certification it is part of that test during the pitot static check as required by 14 CFR 91.411.

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there is no reason to do any of that because you don’t need to comply with 14 CFR 91.411 as you are not certifying an IFR system.

[from the hidden camera in the back room of the repair shop]