BOAC,
It may be, of course, that Capn Bloggs is not aware of the relationship between G/S and R of D for a given glidepath?
Don't worry, I've got a bit of an idea. CDA NPAs, both DB and Non DB, have been routine for our ops for over 25 years. My point was that "pointing" the nose at the FAF, hoping you get the to MDA
at the point where the 3° approach path/PAPI coincides with the MDA, is not the ideal way to do it. FPA is not the be-all-and-end-all: one good gust of wind, turbulence (or perhaps selection of final flap) will bump the aeroplane off the original 3° and FPA will not get you back to the intended approach path. It will maintain/re-establish a 3° FP, but not back to the original, intended descent path. FPA is a reactive control, not a pro-active, guide-to control.
The only
proper way to do a CDA on an NPA is to either use the DB 3° coded approach, follow a charted 3° profile (we've had these on our AIP charts for many years - catch up world) or create your own profile using the DME or GPS to a suitable distance reference waypoint. If you can't do that, then getting to the MDA nice and early and steaming in is the way to go. Sit there fat dumb and happy. Get Visual, land. If you don't get visual, continue steaming along, level, to the MAPt then do the missed approach. Easy.