There's obviously disagreement on this thread as to whether the design and representation of the RNAV (GNSS) NPA's are a problem. Whether or not the design and representation is an issue, Blogg's post above has illustrated one thing that reduces one's situational awareness immeasurably in a RNAV (GNSS) NPA - lack of a moving map. Take that little airplane symbol tracking along the red lines away and you are denied another tool that can help avoid disaster - not only can you see the abbreviation for the next waypoint, but you can see where on which segment of the approach you are flying and match that to the approach chart. A separate CDI can represent x-track accuracy in a format we're all used to - but you do need to know the scale used for the segment.
I fly SPIFR RNAV (GNSS) NPA's a LOT, hand fly a lot of 'em for practice and would not like to tackle any of them with a serious workload without a moving map. Surely it's also the least that the travelling public deserve. I also prefer the ASA DAPs to Jepps for RNAV approaches.
One thing that has always bugged me about the LHR accident is how a decision could be made to go below the minimum altitude that must be maintained from LHRWI until LHRWF (2200') without noticing that the GPS and the annunciator hadn't kicked into APP mode (usu happens within 0.5 NM of FAF). This is a vital final check as to whether to continue the approach, if no APP mode indicated, can't descend further (then try same or other RNAV (GNSS) NPA again or in the LHR case, go on over the top to to the RWY 30 NDB). The LHR accident happened about LHRWI (IIRC) and I have never seen APP mode kick in so far away from the FAF.
Edited
6/4/07: I have since viewed the animation from the ATSB site - the Metro was at ~2200' crossing FAF, so my "IIRC" was incorrect - the ACFT did not go below 2200' until after the FAF, so the "APP mode" observation I made above is irrelevant to the case. Oops.
