On Sunday, May 20, 2018 at 9:06:11 AM UTC-7, 2G wrote:
On Saturday, May 19, 2018 at 9:52:05 AM UTC-7, jfitch wrote:
On Saturday, May 19, 2018 at 8:51:12 AM UTC-7, 2G wrote:
On Saturday, May 19, 2018 at 7:23:32 AM UTC-7, jfitch wrote:
On Saturday, May 12, 2018 at 3:10:57 PM UTC-7, 2G wrote:
On Thursday, May 10, 2018 at 11:35:08 PM UTC-7, Bob Kuykendall wrote:
On Thursday, May 10, 2018 at 7:48:12 PM UTC-7, 2G wrote:
So, you think I am full of ****...

I wouldn't have put it in so few words.

If you do call the FAA for guidance, they will likely refer you Advisory Circular AC 43-210A (https://www.faa.gov/documentLibrary/...AC_43-210A.pdf) “Standardized Procedures for Obtaining Approval of Data Used in the Performance of Major Repairs and Major Alterations.” This covers what constitutes a minor repair:

“3.2.2 Determine the Repair or Alteration Classification. Determine if the repair/alteration is a minor change in type design (as defined in 14 CFR part 21, § 21.93) to the product’s type design; and if so, is it a major or a minor repair/alteration. To determine if a repair/alteration is major or minor, refer to part 43 appendix A. Figure 3-2, Determination of Major or Minor Alteration or Repair, is a flowchart of the field approval evaluation process based on part 43 appendix A.”

The regulation referenced, 14 CFR part 21, § 21.93, explicitly defines what constitutes a minor repair (https://www.law.cornell.edu/cfr/text/14/21.93):

"(a) In addition to changes in type design specified in paragraph (b) of this section, changes in type design are classified as minor and major. A “minor change” is one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the product. All other changes are “major changes” (except as provided in paragraph (b) of this section)."

The addition of instrument not required for certification constitutes a minor alteration (unless it affects the performance of required instrumentation) and meets the above criteria. An FAA airframe inspector are available to answer any questions concerning these regulations. My experience with FAA inspectors is they are really trying to make compliance as easy as possible and are not trying to make your life miserable.

Tom

That definition of minor change leaves very wide latitude for minor changes. Also great latitude for judgement about what is considered a minor change.

I totally disagree. 14 CFR 21.93 clearly states:

A “minor change” is one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the product.

If ANY of these conditions are met, it is a major change requiring the attendant paperwork. You don't make this judgment, your A&P does. And I would consult with an IA who is authorized to sign off on major changes.

Tom

There is very little you can do to the panel that would affect any of those things. As long as the required instruments stayed in place, you could replace the entire panel with a homebuilt one made from crumb board from Home Depot, complete with a lawn sprinkler controller and a hair dryer. Weight, balance, structural strength, reliability, operational or other characteristics? No appreciable affect, hence minor change. Yeah the A&P would need to sign. He's the one with the great latitude for judgement.

Now you are being silly. Adding ADS-B Out to a standard category aircraft, for example, IS NOT a "minor" change, requiring an STC.

Tom

I believe that is wrong, but will leave it to others to argue the case. It may be true that adding ADS-B out TO MEET CARRIAGE REQUIREMENTS in a standard category aircraft requires an STC. Regardless, that is very different than Scotch taping a PDA to the dashboard, which is what this thread is about.. I can add 12 of those, not tell a soul, and be completely legal - as long as they don't weigh too much .