Sos! Rnp=wtf??! ...---...

GravityHater

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I need a plain language concise easy to read simple explanation of what RNP is, how we interact with it, what it all means to us on a practical basis.
I have read AC90-100 and the AIM and I am still WTF on this topic.
Any valid help is appreciated. Is there a text, a chapter of a text, a compendium that the average joe pilot can use to say, 'hey, I get it!'
Thanks
 

minitour

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It's those damm RNAV SID's, isn't it?

"USE RNP 1.0" "USE RNP 2.0" :eek: WTFO?

-mini
 

Frmr Avro Drvr

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GravityHater said:
I need a plain language concise easy to read simple explanation of what RNP is, how we interact with it, what it all means to us on a practical basis.
I have read AC90-100 and the AIM and I am still WTF on this topic.
Any valid help is appreciated. Is there a text, a chapter of a text, a compendium that the average joe pilot can use to say, 'hey, I get it!'
Thanks
RNP: REQUIRED NAVIGATION PERFORMANCE - A statement of the navigational performance necessary for operation within a defined airspace. The following terms are commonly associated with RNP:
a. Required Navigation Performance Level or Type (RNP-X). A value, in nautical miles (NM), from the intended horizontal position within which an aircraft would be at least 95-percent of the total flying time.

Required Navigation Performance (RNP) Airspace. A generic term designating airspace, route (s), leg (s), operation (s), or procedure (s) where minimum required navigational performance (RNP) have been established.


This says that for an aircraft to operate in RNP-2 airspace, the Area Navigation (RNAV) system in that aircraft must be able to accurately fix its position to within 2 nm of its actual position 95% of the time. Reduced Vertical Separation Minima (RVSM) takes care of making sure two aircraft don't touch metal in a vertical direction and RNP makes sure that two aircraft don't touch metal in a horizontal separation direction. If aircraft have a certified RNP level, ATC can, in theory, position aircraft closer in a horizontal direction at the same altitude.

It doesn't mean much to an average pilot. There is certain airspace that has certain required RNP levels and your aircraft has to meet it.

More Info:

http://www.jeppesen.com/download/briefbull/den01-j.pdf

That is the extent of my limited knowledge on RNP. I am sure there are people with more info, but until they pipe up, I hope this helps.
 
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GravityHater

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Ah! A nibble. A bite!

I have an idea of what it means and how it works.

Now I need to know (for flying in the US) when we must pay attention to it and when we are able to comply.

I assume (couldn't find a reference ANYwhere) that all GPS/RNAV units must be *performing* to a certain RNP level (otherwise, how could we rely on them for position accuracy at all?)
But it also appears that despite this, some are not *certified* to be used as RNP units. (these ones do not describe it in their manuals, do not display the current RNP level on their screens)

I am seeing some sids/stars that have an RNP requirement on part of their course lines, and the Jepp pdf which AD posted shows charting symbols so we can identify them. But, what do we do if we are assigned an RNP STAR and have no RNP capable nav unit? What is the PCG terminology? "Unable Neckrock6 STAR, ma'am; N123 is RNP-unable at this time."?
Kind of like the RVSM thingy?
 

cezzna

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Well on Sept. 1 new equipment suffixes came out. You can look them up on the internet. If you are not RNP capable you file under a different suffix and they won't be assigned to you. I have to warn you though the new suffixes are quite confusing. If you're not sure if your box is certified call the manufacturer or an avionics shop. they should be able to tell you if it is certified or not for RNP sids and stars.
 

TonyC

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cezzna said:
If you are not RNP capable you file under a different suffix and they won't be assigned to you.
Shouldn't and won't are two different things. Every week I run across controllers that don't seem to understand that /W means I can do RVSM but I can't RNAV. Yeah, I'll take direct to the other side of the country, but I'm gonna need a heading to get me pointed there, please. :)


You SHOULD not be assigned a procedure that requires equipment that you do not have. However, in the event a controller makes a mistake (it has been known to happen on very rare occassions :) ) you should decline a clearance for a procedure you're not equipped to fly.





.
 

Thedude

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Got a link for those new equipment suffixes?
 

puddlejumper

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This is from the July 31, 2005 AFS-410 document revising the Aircraft Equipment Suffix Table. LINK /W aircraft are still expected to have limited RNAV capability, just not the Advanced RNAV to comply with Type A or B Terminal RNAV procedures.

c. Aircraft with RNAV Capability. For flight in RVSM airspace, aircraft with RNAV and RVSM capability, but not Advanced RNAV capability, will file “/W”. Filing “/W” will not preclude such aircraft from filing and flying direct routes in enroute airspace.

Here's a link to an FAA document to determine if your installed equipment is capable of complying with Type A or B RNAV procedures per AC 90-100. AC90_100 Compliance Table.
 

pilotmiketx

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Your AFM needs to say that the aircraft is "Approved for RNP X". This is completely separate from RVSM and International RNP requirements. I've got a letter from Collins on my desk addressing this but have been too busy flying to read it (those Jepps are gonna have to wait, too)
 

TonyC

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puddlejumper said:
This is from the July 31, 2005 AFS-410 document revising the Aircraft Equipment Suffix Table. LINK /W aircraft are still expected to have limited RNAV capability, just not the Advanced RNAV to comply with Type A or B Terminal RNAV procedures.

c. Aircraft with RNAV Capability. For flight in RVSM airspace, aircraft with RNAV and RVSM capability, but not Advanced RNAV capability, will file “/W”. Filing “/W” will not preclude such aircraft from filing and flying direct routes in enroute airspace.

Here's a link to an FAA document to determine if your installed equipment is capable of complying with Type A or B RNAV procedures per AC 90-100. AC90_100 Compliance Table.
Interesting. The subparagraph you've quoted seems to contradict a line from the first subparagraph of the same document and the table at the end.


1. Introduction. An effective time of “0901 UTC” is added for this update.

a. Effective September 1, 2005 at 0901 UTC, when filing an FAA Flight Plan (FAA Form 7233-1), operators will use a new set of aircraft equipment suffixes to indicate Advanced RNAV and RVSM capabilities. Either “/J”, “/K” “/L” or a newly defined “/Q” will be filed to indicate Advanced RNAV and RVSM capabilities. “/W” will continue to indicate RVSM capability only.


The last line of the Suffixes / Equipment Capabilities table shows /W is simply "RVSM." There is no mention of RNAV capability, Advanced or otherwise.


Maybe that's why the controllers are still confused.

:)




.

 
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