Rnp

[Kenny Rogers]

RNP will be used by certain airlines at the airport where I control air traffic. My question is:

How is this technology interfaced by the pilot? With the FMC? If so, how does it appear? A series of legs with speed/altitude restrictions for each?

Kenny Rogers

[Dream Land]

Are you refering to RNP - Required Navigational Performance?


Dream Land:confused:

[DeeTeeS]

Kenny,

No experience with other than on Oceanic, Class II Navigation where traffic is separated by manual position reports and the pilot is expected to fly at filed Mach or whatever asked.

I did operate B737-400 EFIS with RNP in the FMC but of course never used it and yes, from my limited knowledge, the FMC has inputs on each leg for the requested crossing time with a resulting calculation of required speed in order to comply. Also, as I seem to remember it will give the pilot while still on the ground the takeoff time in order to comply.

[Kenny Rogers]

Thanks for the replies. You've answered my question regarding RNP from a cockpit perspective. Required Navigation Performance will be used by Westjet Airlines to certain Canadian airports that have terrain issues. From what I understand, RNP approaches can guide an aircraft that is in IMC conditions around all terrain down to 250' AAE. I think this is absolutely fascinating technology. I'm sure it's nothing new, but it is one huge step beyond ground-based navigation instruments, such as ILS's and NDB's. With this technology will come huge fuel savings for everyone, and hopefully a smoother operation from an air traffic perspective.

If anyone has anything to add (or correct) to this thread I would greatly appreciate it, as I am trying to gain an understanding of how RNP will change air traffic procedures.

Ken

[411A]

For approaches, standard instrument departures/arrivals, RNP0.03 is required. "Tis in service now at selected airports in the USA, KLAS being the first, I believe.

[Kenny Rogers]

Regarding RNP approaches, sids, and stars:

I am familiar with general FMC operations (selecting sids, stars, approaches, and modifying routes) but how do RNP procedures appear on the FMC? Are they a series of legs, just like a typical flight plan?

Ken

[Dream Land]

In the aircraft I fly, RNP approches are reffered to as RNAV approaches, a straight in approach consisting of usually two waypoints for the initial and final and an additional waypoint for the missed approach procedure. Departures begin from the departure end of runway and route you as needed for the airport, no navaids required.

Dream Land

[411A]

In addition, NOTAMS indicate when these ops are required...to be checked very carefully.

ATC is watching...as expected.

[reynoldsno1]

There seems to be a basic misunderstanding about RNP . RNP is not "new technology", or a navigation system as such. It is a concept based on the probablility of navigation containment within an area of airspace, or for a defined procedure. By stating a required RNP value, the air navigation service provider is saying that the aircraft systems and the ground navigation infrastructure combined must meet the navigation accuracy defined by the RNP.

A piece of airspace supported by an airborne ADF and a single NDB could be assigned an RNP value - just rather a large one.

In practice, RNP is closely associated with RNAV systems since it is these that provide the "extra" accuracy when combined with the ground navigation infrastructure. As an example, domestic enroute operations would probably be assigned RNP4 (4=4NM). Non-precision approaches are RNP0.3. Most RNAV systems can be certified to a given RNP value, will display their capability at any given time, and operate to a given RNP.

[OzExpat]

Kenny, I assume that you're an ATCO who is trying to make sense of it from an ATC perspective? If so, you might find that separation standards might be reduced due to the accuracy of equipment meeting a particular RNP standard. This will probably only be of value when the aircraft is in enroute flight.

In any event, nothing will change until your local separation procedures are changed to allow for it. Until that happens, RNP will probably not make much difference to ATC. It will, however, make a massive difference to aircraft operations - which might free up approach airspace more quickly, thereby (maybe) allowing other aircraft to commence their approaches sooner.

[Kenny Rogers]

Thanks for the replies. Now I'm all clear on RNP. The proposed RNP approaches in my area, which will supposedly be routes carved around mountains and through valleys for fuel/time savings, sound fascinating.

Ultimately, whatever saves you guys (gals) fuel makes us happy.

Ken

[411A]

Not only fuel savings, but the ability to fit more aircraft in designated airspace, for both arrivals and departures.
Will be fitting shortly a second GPS to my private aircraft to have the ability to comply with RNP0.030, especially for departures from KLAS.
This will become very important in the coming months, so i'm told by those in the TRACON.

[Dan Winterland]

Most FMCs already give the RNP against ANP (Required Nav Performance versus Actual Nav Performance). There is always a RNP. On the North Atlantic it is 12 (I think). Over most of Europe it is 5. But his is to change to 2 on 1 Nov 04. One of the difference is that you have to have a graphic display of Nav track dispalcement which does not mean an HSI swithced to INS instead of Nav. My company is going to have to fit glass Nav displys in it's classic jets as will all operators who want to use RNP2 airspace.

PS: I'm willing to be corrected on any of the figure above.