Duck, I wouldn't worry, the proper FMS aeroplanes are nothing like the Dash 8. That thing is a dinosaur from what I have seen in the descent profile department.
If the 737 is anything like what I fly, you don't select the Required Navigation Performance, in terms of accuracy of tracking; the aeroplane will track as accurately as it can at all times, which is pretty damn good and well within any RNP. It's called the ANP, Actual Navigation Performance. Now, if the ANP drifts out to the RNP (which is either coded into the approach or set by the crew) then you get a warning. As alluded to in a post by Derfred I think it was, the 737 is deadly accurate: at Mildura, Virgin did a Zero/Zero landing on the runway using only a bog-standard cheap charlie RNP LNAV approach (old GPS NPA), similar to that published at Chuuk. As also pointed out by Derfred, this particular approach is a curly one because the MAPt is hit well before the MDA if you are on the 3° slope to the runway. You either accept that on a 3° slope (that could be flown in VNAV/AP) you will never get to the MDA, or you duck below the 3° to get down to the MDA first before the MAPt.
Last edited by Capn Bloggs; 30th Oct 2018 at 05:42.
Reason: MAPt/MDA in wrong order...corrected.