Transponder STC question

[Otto Pilot]

New guy here, with what may be a new guy question.

Without getting into the major vs minor debate, I’m trying to clarify the correct paper trail of a transponder installation.

Is there any advisory circular out there that allows a kind of STC follow on installation of a transponder for VFR, like there is for ADSB installations? I could have sworn I read an AC or policy statement to that effect once, but I can’t find it. Maybe I dreamed it…

 

[Bell206]

Without getting into the major vs minor debate, I’m trying to clarify the correct paper trail of a transponder installation.

Unfortunately any paper trail answer will depend if your xspndr install is a minor or major alteration or if it is a simple part replacement. Maybe detail what you have and what you want to install might get you the answer you're looking for.

 

[flyingron]

There's no difference on transponders for IFR versus VFR. To my knowledge there is no guidance. Depending on what your panel looks like, there may not be any requirement for an STC.

 

[Salty]

If it’s already installed, you have a valid annual and are compliant with 91.413, fly on and fuggetaboddit. JMO

 

[Otto Pilot]

It’s a logbook entry that mentions the transponder install “in reference to” an STC, but without the usual accompanying STC paperwork. While I’m not an A&P, it certainly seems it should be a minor alteration to me, so no STC should have been needed. That’s where the “in reference to” wording confused me.

In regards to the annual comment, that’s a good point. I guess if multiple IA’s have looked at something it’s probably not an actual problem.

 

[Bell206]

it certainly seems it should be a minor alteration to me, so no STC should have been needed.

FYI: not all STC installations are considered major alterations. Given there are several types of STCs, some vendors use the STC process for Part 21 design approvals even though the installation falls under a minor alteration.

but without the usual accompanying STC paperwork.

What STC paperwork are you referring to?

 

[Checkout_my_Six]

permission letters?

 

[John Collins]

If there was a previously installed transponder, then replacing it with another one would usually just be a log book entry. If it was used as the ADS-B Out system, the FAA has provided a policy memo.