On Wednesday, May 9, 2018 at 4:02:34 PM UTC-7, Dan Marotta wrote:
Don't know about gliders yet, but the ADS-B install in my airplane was
accomplished by a shop under an STC.

On 5/9/2018 4:14 PM, Darryl Ramm wrote:
Transponder installs somehow automatically being a major change and therefore requiring a 337 misinformation is my favorite dead horses ass :-) That old chestnut (must have been a Chestnut horse?) is coming up again in the context of ADS-B Out installs. (and the quicj answer there is most should be minor changes, unless there is some other reason the install is a major change).

OK down another rat hole...

"accomplished... using a STC" can means two different things with ADS-B Out..

For 2020 Complaint ADS-B Out you normally need to use an STC as a basis for the pairing of a ADS-B Out tranmitter (e.g. transponder) and GPS Source. And the FAA asks for a "notice only" '337 to be filed with Oklahoma HQ. None of that necessarily makes this a major change, requiring a normal 337 major change to be approved by the FSDO and (typically a STC used as a basis for that approval). This is documented in FAA Policy 8900.362 (yes technically expired but still being followed) that A&P should be aware of. A mistake here seems to be folks assuming they have to do more than the policy exactly says. And usually another example of why you want an experienced glider A&P interpreting this stuff. If the A&P believes the insulation itself *is* a major change then they also need to file a 337 for major change approval with the FSDO.... that should *not* be the case for most glider ADS-B Out installs. (and they will likely immediately run into problems with no STC existing to use as an install basis for any transponder in any glider in the USA, and the typical AML STCs used for that pairing not listing the glider on the AML STC... likely not an issue if all you care about is the pairing being previously approved). If folks incorrectly submit those notice only 337s to the FSDO where they are not required, don't be upset when the FSDO assumes you are seeking major change approval and starts asking for transponder install STCs that don't exist...the FSDO staff are doing what you pushed them to do. I think there should be a type of Hippocratic oath when dealing with regulatory agencies... don't create work/confusion where it does not need to be.

None of 8900.362 applies to experiential gliders and none of 8900.362 applies to TABS installs in certified (or experimental) gliders, since you are not seeking compliance there with 14 CFR 91.225 and 91.227, which is all this policy addresses.