Guys: I admit to not having read the whole discussion. Mea culpa.
I was operating out of a very noise sensitive EU airport for many years. Many major airports had a published low drag CDA profile. Having arrived from a UK operator, and been well taught, my standard profile was CDA low drag. My new local colleagues were not of the same thinking. There was no such philosophy in their region and no published CDA criteria. I battled to introduce it in the airline. Difficult. However, ATC didn't help with their early descents instructions. The ILS platform was 2000'agl. and my F/O's were dragging it in. At night ATC used 3000' for G/S intercept for noise reasons. I asked then why that wasn't also for daytime use. "Because it wasn't in the regs". I now sit and watch a/c drag it in at 2000' all day long. Daft for fuel, daft for noise, daft for environment. The locals are always complaining about noise. Why not raise the ILS platform to 4000'agl? The a/c are arriving from every which direction. If ATC want to cut you in short for spacing reasons, then they can ask for a CDA to whatever finals they need. Why is CDA not a universal airport thing? I've flown for airlines where CDA was SOP. I've flown into German airfields where low noise low drag CDA is published. Why is it not universal practice? This 3.2 slope instead of 3.0 slope is a piss in the pot for noise reasons. Start the slope at a higher height and keep idle thrust till 3.0nm. No level drag in. 3.0 or 3.2 from 6 or 8nm out is a gnat's cock of difference. 3.2 from 2500' agl or 3.0 from 3000' agl. Without the science I can almost guarantee that the latter is less noisy; from 3500' even less so. Is this experiment just another political sop to the uninitiated?