That's where I think you are wrong. The FAA process for issuing an STC is pretty complex and involves substantial fight testing to prove the aircraft performs as required. They aren't going to just accept a list of installed equipment and assume it will work as designed. Here are the FAA steps for an STC:
- Applicant applies for STC
- Familiarization and preliminary type certification board (TCB) meetings
- FAA develops certification program plan
- Establishment of certification basis by FAA
- Applicant submits data for approval
- FAA design evaluation
- FAA and applicant hold specialists and interim type certification meetings, as required
- FAA performs conformity inspections
- Engineering compliance determinations
- Pre-flight TCB Meeting
- Applicant performs ground inspections, ground tests, and flight tests
- FAA reviews manufacturer's flight test results and issues TIA
- FAA performs conformity inspections, witnesses tests, performs official certification flight tests and flight standards evaluations
- Functional and reliability testing
- FAA approves flight manual supplement or supplemental flight manual and holds final TCB meeting
- AEG completes continuing airworthiness determination
- FAA issues STC
I'm expecting that ground/flight testing of N26BY, our 2004 8KCAB SuperD could start next week. I met with my three (count'em: 3) DERs Sunday night to refine the Compliance Checklist appendix in the Project Specific Certification Plan. Two flights will be conducted, one day and one night. The day flight will include several aerobatic figures to verify that pulling Gs won't scramble the avionics required by Parts 91 and 23 for IFR operation. A co-owner (insurance) safety pilot (who weighs 100 pounds...so not me) will accompany the Flight Test Pilot DER for the day flight. No acro during the night flight. Ground testing required to demonstrate compliance (mostly for "functionality") will be performed before both flights.
A ground/flight test report will be written by the Avionics and Flight Test Pilot DERs; the Flight Analyst DER will review those tests that require a Flight Analyst DER for approval.
The DERs were "fully delegated" to support the STC, which means that there is minimal direct participation by the members of the Certification Branch Project Team until the final (revised) version of Project Specific Certification Plan is submitted along with specified "deliverables" (mostly the test report and AFMS) for Cert Branch Project Team approval.
The Cert Branch Project Team didn't want to conduct any of the meetings listed above: that was one of the advantages of the "full delegation" to the DERs. A TIA was not required; the DERs will verify conformance with the "FAA approved" data the Part 145 repair station (which is a Garmin Dealer) used for the installation. The data comprised Garmin STCs: AMLs, Installation Manuals, forms 337, and installation checklists and logs. This was a big deal because I didn't have to hire a DAR for the TIA and the airplane category wasn't changed to "Experimental R&D" for the flight test.
The reason I searched this thread is that I must post several placards and was hoping there was an owner of an aerobatic and IFR Citabria 7KACB with a placard that looks something like this:

It's a little strange to me that the DER wants this placard posted for flight test before the STC that approves IFR operations has been approved, but it's a Part 23 requirement.
I asked our Good Friend Chad at ACA for a placard like it, but so far, no joy. I will also post this placard:
MAGNETIC COMPASS MAY DEVIATE AS MUCH AS 30° WHEN PITOT HEAT IS ON.
BTW: it doesn't deviate that much when pitot heat is on, only about 5°, but that's the placard wording for the Scout with a heated pitot tube.
Does anyone with that rare acro/IFR Citabria have a part number for either of these placards? I'd rather have ACA placards than ones I create.