Looking for RNP...
My answer is that both RNP 1 and RNP 10 are using in different areas of operation and for that reason they canīt be compared between each other.
Areas of operation:
Oceanic and remote continental
Oceanic and remote continental airspace is currently served by two navigation applications, RNAV 10 and RNP 4. Both rely primarily on GNSS to support the navigation element of the airspace. In the case of RNAV 10, no form of ATS surveillance is required. In the case of RNP 4,
ADS contract (ADS-C) is used.
Continental en-route
Continental en-route airspace is currently supported by RNAV applications. RNAV 5 is used in the
Middle East (MID) and
European (EUR) regions, but as of 2008, it is designated as B-RNAV (Basic RNAV in Europe and RNP 5 in the Middle East). In the
United States, RNAV 2 supports en-route continental airspace. At present, continental RNAV applications support airspace specifications which include
radar surveillance and direct controller-to-pilot
voice communications.
Terminal airspace: arrival and departure
Existing
terminal airspace concepts, which include arrival and departure, are supported by RNAV applications. These are currently used in the European (EUR) Region and the United States. The European terminal airspace RNAV application is known as P-RNAV (Precision RNAV). Although the RNAV 1 specification shares a common navigation accuracy with P-RNAV, this regional navigation specification does not satisfy the full requirements of the RNAV 1 specification. As of 2008, the United States terminal airspace application formerly known as US RNAV Type B has been aligned with the PBN concept and is now called RNAV 1. Basic RNP 1 has been developed primarily for application in non-radar, low density terminal airspace. In future, more RNP applications are expected to be developed for both en-route and terminal airspace.
Approach
Approach concepts cover all segments of the instrument approach, i.e.
initial, intermediate
final and
missed approach. They will increasingly call for RNP specifications requiring a navigation accuracy of 0.3 NM to 0.1 NM or lower. Typically, three sorts of RNP applications are characteristic of this phase of flight: new procedures to runways never served by an instrument procedure, procedures either replacing or serving as backup to existing instrument procedures based on different technologies, and procedures developed to enhance airport access in demanding environments (RNP APCH and RNP AR APCH).
RNP approaches to 0.3 NM and 0.1 NM at
Queenstown Airport in New Zealand are the primary approaches used by Qantas and Air New Zealand for both international and domestic services. Due to terrain restrictions, ILS approaches are not possible, and conventional VOR/DME approaches have descent restrictions more than 2,000 ft above the airport level. The RNP approaches and departures follow curved paths below terrain level.
And, do not forget: Special Aircraft and Aircrew Authorization Required