RNP procedures aren't created only on terraneous approaches, it could be simply a backup procedure in busy airports like KEWR in case an ILS goes under maintenance, or are not installed at all. It's almost as precise as an ILS (or even more in some cases).

Here are 2 links from Boeing that talks about RNP, IAN, LNAV, and VNAV. The terminology can be quite confusing. http://www.boeing.com/commercial/aeromagazine/aero_22/737approach_story.html http://www.boeing.com/commercial/aeromagazine/aero_16/navigation.html Hope this helps. Think of RNP as a containment area that follows the approach path. I recommend doing an advanced search in Adobe Reader by typing IAN and another search on RNP. The IAN in chapter 4 will show the indications for an RNP approach. Quick Ref from the web links REQUIRED AND ACTUAL NAVIGATION PERFORMANCEThree concepts need to be understood when discussing required navigation performance (RNP) operations: the RNP required by a regulatory agency for a defined flight path, the RNP rating of a given airplane model, and the actual navigation performance (ANP) of an airplane during flight. The first two concepts often are referred to as RNP.RNP extends the capabilities of modern airplane navigation systems by providing a precise characterization of airplane navigation performance. The navigation accuracy of an airplane is based on its system capabilities rather than specific ground-based navigation aids. RNP defines the navigation accuracy that an airplane must have to operate on a specific route segment. INTEGRATED APPROACH NAVIGATIONIntegrated Approach Navigation (IAN) is an approach option designed for airlines that want to use ILS-like pilot procedures, display features, and autopilot control laws for nonprecision (Category I) approaches. This option does not require additional ground facility support. REQUIRED AND ACTUAL NAVIGATION PERFORMANCENavigation Performance Scales (NPS) is a new display feature that integrates the current lateral navigation (LNAV) and vertical navigation (VNAV) with actual navigation performance (ANP) and required navigation performance (RNP).

Hello All, This post is an extension of the Post raised by Flyer767 on 1.9.11. I am interested in using RNP but some simmers are using it for Approaches. I was under the impression that the use of RNP, having watched a DVD of Westjet, that RNP was used at airports where there were difficult terrain and the landing airport had NO radio navigation facilities and the airline companies had installed routing in the aircraft FMC to accommodate these airports and that the crew used VFR for landing. I havethe PMDG Flight Crew Training Manual which mentions RNP but does not give instruction on its use. I have also searched the Net for a Tutorial but without any real success. Is there anyone in this Forum who has the necessary knowledge. Much obliged. richard welsh.

Hi You are talking here about RNP-AR (RNP-Authorisation Required) type approaches. It can be flown in specific conditions and not restricted to VMC. Hope this clarifies Regards Jay Cargo

Quite an intricate topic and a lot of usefull and informative ibfo from users. Thanks learnt a lot from this topic. P.S. Hope the RNP radius to fix is one of the items being implemented in SP1 !!

Not quite. The final approach segment for a GPS/RNAV approach still has to be straight, in which case you might as well install an ILS. Not practical if there's a mountain in the way. RNP allows not only lower minimums, but allows radius to fix (curved approach) segments to avoid the terrain you otherwise wouldn't be able to.

Except ILS costs a lot of money and you need to set one up for each runway. RNP doesn't enable curved paths - the FMS does.

Let's take for example the published Rnav approaches for KEWR 4R:1. Rnav (RNP) Z RWY 04R2. Rnav (GPS) Y RWY 04R They are, for all intents and purposes, one and the same! The RNP plate clearly states GPS required, which needless to say is also required for flying the GPS plate. They have the same fixes, same vertical profile, and same missed approach! So why not forgo the publication of the RNP plate and simply publish one RNAV (GPS) plate listing the minima for Lnav/Vnav 0.3 RNP and 0.15 RNP alongside the other minima published (LPV, Lnav, circling)? And then there's the whole issue of some countries calling it GPS others calling it GNSS... it took a long time to figure this stuff out by myself and I think things could be simpler.

The ICAO have put out a publication they will see the disappearance of RNAV (GPS) and RNAV (GNSS) approaches. Instead these will be labelled RNP (xx) approaches where "xx" is is a code that indicates what kind of guidance is required (lateral, vertical). These include LP and LPV, etc. GPS refers to the NAVSTAR system run by the US DoD. GNSS is a term that encompasses all satnav systems including those being set up by the EU, China, etc.

RNP doesn't enable curved paths - the FMS does.

I didn't say RNP enabled curved paths. I said RNP [approaches] allow for them.

Ok Brad, that makes sense when RNP is used to fly around otherwise inpenetrable terrain... but what about in KEWR's case. There's no terrain and the RNP approach is as straight as the Empire State!

In the case of Newark, the RNP approaches help with airspace, I think staying out of JFK.

You can set missed alt in the MCP when you're in approach mode i.e. within 2 miles, 2000ft AAL or past the FAF can't you? IIRC....

None of that info sounds familiar to me. Where did you find that?

None of that info sounds familiar to me. Where did you find that?

Got my wires a little crossed, and didn't remember things quite correctly, but here's what I've found: Firstly, 5.67 of the FCTM recommends the method you mentiond which is to set the the missed approach alt in the MCP, when you're 300ft below that atl. The thing I was thinking of was from FCOMv2 section 11.31.37 which states the following:

ApproachThe FMC transitions to “on approach” when the airplane is within:•2 NM of the first approach waypoint (including approach transitions such as arcs and procedure turns), or•2000 feet of airport elevation, whichever occurs first. When the FMC is “on approach”, the following features are available:•UNABLE RNP alerting levels are higher•when preparing for a missed approach and the MCP altitude is set at least 300 feet above the current airplane altitude, VNAV will continue to command a descent•if the airplane is more than 200 feet below the vertical path, VNAV commands zero vertical speed until intercepting the path.

Doesn't really change anything though, you'd still fly it as you said. Interesting none the less!