From what I’ve gleaned from other forums, I think it means that under 2500lbs there will be the option of registering your aircraft in a Non Commercial category, which will be very similar to the experimental category. Supervised maintenance by the owner will be possible here and also installing non certified avionics and other stuff that promotes safety. Aircraft can then by brought back to Commercial standard by complying with its original TC. I think it’s still TBD how much and what type of mods will be allowed in the Non Commercial bracket. But even in the Commercuial category, changes that promote safety will be allowed. Examples like AOA sensors, avionics, seat belts etc. Plus, for any new certification the process will become cheaper and quicker. There’s talk about 30% reduction in costs, at least. To be implemented by the end of 2015, but we all know it’s probably going to be extended.
This is a great step in the right direction. It will not save GA, but at least it might halt the decline a little. Plus it might spur innovation and manufacturers that have been on the fence with certification (RV for example), to probably jump in.
The FAA have published the NPA on significant changes to Part 23, which amongst other things will hopefully simplify certification for modern avionics.
https://www.gpo.gov/fdsys/pkg/FR-2016-03-14/pdf/2016-05493.pdf
Two years late…. Probably more relevant for manufacturers bringing new products to market than for existing airframes….contrary to the great hopes people had…although it remains to be seen whether “performance based approvals” translates into being able to install something like a Garmin GX3 into a certified aircraft without an STC and a much simplified field approval process… Or not….
What we need is an Executive Summary 
@Peter, look inside the document, it is already there.
My first (and unqualified, mind you) impression about this document is that some clauses seem to leave too much open for interpretation by the individual DAR. Unless, of course, all FAA DARs are apples of the same tree…
My impression is that this will not make certification as such easier, but it does mean that the designer will have larger freedom in choosing a design which will be certifiable.
More of the same from the FAA, …but when will EASA follow…
