Making a GPS IFR legal

[DesertNomad]

My shop is installing a GTN750 in my Dakota. It is replacing the GNS530W that was previously installed. My airplane is on the approved STC list so I gather that after it is installed, they do 1 (or maybe 3) approaches, file a 337 and then I am legal to file and fly IFR?

Do I have to wait for some sort of approval from the FAA / FSDO?

This thread (post #19) says:

"Most will document the installation with a 337, but the FAA approved data is from the STC, and the FSDO does not get involved in the process. You just mail in the copy of the 337 to Oklahoma City for filing. To get the FAA approved AFMS, all you need to do is to print it out, fill in your aircraft data, check a few option boxes, and put it in the POH. No 337 is required to get it approved as it already is approved."

https://www.pilotsofamerica.com/community/threads/ifr-certified-gps.46529/

Is this accurate?

 

[bradg33]

The FSDO, or FSO now, does not get involved for an STC'd install unless your installer needs to deviate from the STC. You only need to do whatever tests or test flights (if any) that are required by the install manual, which I haven't reviewed for the GTN750, but it should spell it out.