RNAV Approach or RNP Approach how to read Chart?

[downscc 1,327]

 

 

RNAV does not use ground-based navigation

 

I read it does?

 

Kyle is ahead of my... what he said.  Also, in the context of current systems RNAV is space-based augmented by WAAS/SBAS.  I am old enough to remember VOR-based RNAV using the King KNS-80 so in that context RNAV uses ground-based navaids... but, let's be reasonable with definitions and keep the context current.

[Akila 39]

OK, Now I am really confused.

I know what Navaids are and they are not RNAV nor RNP.

what I don't understand is, you guys saying that if a chart has RNAV (GNSS) on it it means RNP required and if no (GNSS) is present than it is a normal RNAV?

That is rather confusing, GNSS is a simple European naming for GPS.. also RNAV needs GPS to perform such navigation,

then how does GNSS (EU term for GPS) on the chart makes it RNP when all it means is that GPS  is needed on board.

Also RNAV equipped Airplanes have GPS on board or they will not be able to RNAV...  

 

RNAV (GNSS) - to me it sounds that you are required to have a GPS on board, that's it.

[skelsey 765]

 

 

OK, Now I am really confused.
I know what Navaids are and they are not RNAV nor RNP.
what I don't understand is, you guys saying that if a chart has RNAV (GNSS) on it it means RNP required and if no (GNSS) is present than it is a normal RNAV?
That is rather confusing, GNSS is a simple European naming for GPS.. also RNAV needs GPS to perform such navigation,
then how does GNSS (EU term for GPS) on the chart makes it RNP when all it means is that GPS  is needed on board.
Also RNAV equipped Airplanes have GPS on board or they will not be able to RNAV...  
 
RNAV (GNSS) - to me it sounds that you are required to have a GPS on board, that's it.

 

Told you the chart naming was confusing!

 

Firstly, as far as I'm aware, all chart providers/aviation organisations are phasing out the "GPS" wording in favour of "GNSS" -- because GPS is (as you know) a specific system run by the US military, whereas GNSS is a generic term referring to all the various satellite navigation systems.

 

To deal with the question about RNAV (GNSS) -- here's a quote from the UK CAA website that explains it:

 

 

 

The instrument approach procedures associated with RNP APCH are entitled RNAV (GNSS) to reflect that GNSS is the primary navigation system. With the inherent onboard performance monitoring and alerting provided by GNSS, the navigation specification qualifies as RNP, however these procedures pre-date PBN, so the chart name has remained as RNAV.

 

So an RNAV (GNSS) approach is an RNP approach, requiring the aircraft to be authorised for RNP APCH operations. But for historical reasons the chart does not have RNP in the title.

[scandinavian13 5,192]

 

 

RNAV (GNSS) - to me it sounds that you are required to have a GPS on board, that's it.

 

If you're in FAA-land:

RNAV(GPS) - RNP optional.*

RNAV(RNP) - requires RNP (and authorization required, or "AR").

 

*Our GNSS approaches - called WAAS or LAAS - are simply added as lower minimum versions of RNAV(GPS) approaches as "LPV." RNP is not required, but you use higher minimums. If you're flying with GPS only, then you use the highest mins. If you have LNAV/VNAV, then you can use those lower minimums. LPV is the only RNP-required min on those procedures.

 

 

Elsewhere? Good luck...but my understanding is:

RNAV - is not RNP.

RNAV (GNSS) - is RNP (down to 0.3)...probably using ground-based augmentation of some sort (GBAS/GRAS).

RNAV RNP (AR) - is RNP (from 0.3 to 0.1).

 

 

So an RNAV (GNSS) approach is an RNP approach, requiring the aircraft to be authorised for RNP APCH operations. But for historical reasons the chart does not have RNP in the title.

 

Per ICAO, maybe, but even they are falling victim to the GNSS misconception.

 

GNSS simply refers to navigation by satellite system. Putting that on a chart to indicate "RNP" seems very misguided, because it's only when you add GBAS/GRAS that it gets to the level where RNP even comes into play. That's why we have it as RNAV(GPS) with LPV (WAAS/LASS which is equivalent to GBAS/GRAS) listed as a different minimum. Since WAAS/LAAS is implemented in units that run their own RAIM checks, and their precision is much more than RNP 0.1, the RNP would be redundant. RNAV(RNP) is what we list our procedures as, because GNSS or GPS would be too vague.

[Akila 39]

OK here is a chart that has RNAV (GNSS) on it (ICAO).

 

Is this an RNP Req' or not (Regular RNAV)?

If true how did you determine this apart from the Title "RNAV (GNSS)"

 

 

[Jepps are copyrighted]

[scandinavian13 5,192]

is this an RNP Req' or not (Regular RNAV)?

 

No.

 

 

 

if true how did you determine this apart from the Title "RNAV (GNSS)"

 

The only mins listed are LNAV-only. Plus, the M in the vertical profile shows that there's a missed approach point (the threshold of the runway). Both of these mean that the approach is a non-precision approach. I've never seen an RNP non-precision approach.

 

The mins box would also say "RNP" if it was RNP (instead of LNAV).

[Driver170 42]

I think kyle and simon have nailed it on the head

[skelsey 765]

GNSS simply refers to navigation by satellite system. Putting that on a chart to indicate "RNP" seems very misguided, because it's only when you add GBAS/GRAS that it gets to the level where RNP even comes into play. That's why we have it as RNAV(GPS) with LPV (WAAS/LASS which is equivalent to GBAS/GRAS) listed as a different minimum. Since WAAS/LAAS is implemented in units that run their own RAIM checks, and their precision is much more than RNP 0.1, the RNP would be redundant. RNAV(RNP) is what we list our procedures as, because GNSS or GPS would be too vague.

 

I agree -- the chart titling is confusing!

 

As I've found the quote about RNP (AR) per the UK CAA, I'll reproduce it here for completeness:

 

 

RNAV (RNP) approach operations are GNSS-based and flown using chart procedures titled RNP. Note: FAA charts may be labelled RNP (SAAAR). This type of approach operation is typically flown at aerodromes with difficult terrain or in challenging ATC environments and may require an RNP as low as 0.1 NM. The required RNP will be labelled on the chart next to the minima. Aircraft will require certification in accordance with EASA AMC 20-26 and crews should be specifically trained for each RNAV (RNP) Approach operation.

Any EASA AOC or private operator wishing to carry out such approach operations must hold an approval issued by the State of aircraft registry and may require special permission from the State of the aerodrome.

 

 

 

OK here is a chart that has RNAV (GNSS) on it (ICAO).

is this an RNP Req' or not (Regular RNAV)?

 

if true how did you determine this apart from the Title "RNAV (GNSS)"

 

You'd have to check the Jeppesen chart legend to see how they title their charts!

The only mins listed are LNAV-only. Plus, the M in the vertical profile shows that there's a missed approach point (the threshold of the runway). Both of these mean that the approach is a non-precision approach. I've never seen an RNP non-precision approach.

 

The mins box would also say "RNP" if it was RNP (instead of LNAV).

 

Not necessarily true:

 

 

Approach Applications

Approach Applications which are classified as RNP Approach (APCH) in accordance with ICAO Doc 9613 Performance Based Navigation (PBN) Manual (and ICAO state Letter SP 65/4-10/53) give access to minima (on an Instrument Approach Procedure) designated as:

• LNAV (Lateral Navigation) – This is a Non-Precision Approach with Lateral navigation guidance provided by Global Positioning System (GPS) and an Aircraft Based Augmentation System. (ABAS) Receiver Autonomous Integrity Monitoring (RAIM) is a form of ABAS.  

 

Full information (and a handy diagram): http://www.caa.co.uk/default.aspx?catid=1340&pageid=13338

[Driver170 42]

That chart is what it says RNAV (GNSS) RNP. Whats in the brackets is what you need to carry out that 3D APV

Also that chart is NPA 2D approach with an MDA. You will have to add company mins to that MDA.

[Akila 39]

 

No.

 

 

 

 

The only mins listed are LNAV-only. Plus, the M in the vertical profile shows that there's a missed approach point (the threshold of the runway). Both of these mean that the approach is a non-precision approach. I've never seen an RNP non-precision approach.

 

The mins box would also say "RNP" if it was RNP (instead of LNAV).

 

 

It is not RNP, even though it has RNAV (GNSS) on the chart tile?

 

so in that case the claim that was heard here before that claims if a chart has RNAV (GNSS) in the tile is an RNP Req, is not true?

we back to score one.

how do we know for ICAO charts what is RNP Req or not?  :mellow:  :(

 

Just in case you might suspect JEPPESEN Chart is the issue, here is the Original AIP Chart.

it also states RNAV (GNSS) 

 

[Driver170 42]

Also notice it doesn't say NA TEMP BELOW -XX

 

Because its already been cold temp corrected

That chart is an RNP

1 RNAV(GNSS) = RNP approach

2 RNAV(RNP)= RNP AR approach

 

So all 2 are RNP approaches

 

Or...

 

RNAV (GNSS) Approach (RNP APCH)

RNAV (RNP) Approach (RNP AR APCH)

 

 

 

This is from CAA

 

 

These are sometimes called RNP Approach Operations, they are GNSS-based and flown to minima labelled LNAV and LNAV/VNAV on a chart titled RNAV/GNSS.

 

LNAV approach operations are flown on Non-Precision RNAV(GNSS) procedures which are charted to a Minimum Descent Altitude (MDA).

 

LNAV/VNAV approach operations are flown with vertical guidance from the aircraft's barometric altimetry system (Baro VNAV) on an RNAV (GNSS) approach procedure, and are charted with a Decision Altitude (DA).

 

Any EASA AOC operator wishing to carry out such approach operations must hold an approval issued by the state of aircraft registry. Private operators do not currently require a formal approval.

[Akila 39]

Also notice it doesn't say NA TEMP BELOW -XX

 

Because its already been cold temp corrected

That chart is an RNP

1 RNAV(GNSS) = RNP approach

2 RNAV(RNP)= RNP AR approach

 

So all 2 are RNP approaches

 

Or...

 

RNAV (GNSS) Approach (RNP APCH)

RNAV (RNP) Approach (RNP AR APCH)

 

but "scandinavian13" claims it is not (he has a valid point there explaining why)

http://forum.avsim.net/topic/467875-rnav-approach-or-rnp-approach-how-to-read-chart/page-2#entry3231030

 

 

that means relaying on the Title "RNAV (GNSS)" alone to determine rather it is an RNP or not is not sufficient.

that means the UK RNP publication that was mentioned above is incorrect 

[skelsey 765]

 

 

that means relaying on the Title "RNAV (GNSS)" alone to determine rather it is an RNP or not is not sufficient.
that means the UK RNP publication you mentioned above is incorrect 

 

If it is an ICAO chart, RNAV (GNSS) means it is RNP. Just because there is no vertical guidance does not mean it is not RNP, as explained in the CAA link above.

 

FAA charts may differ as explained by Kyle.

[Driver170 42]

Thankyou simon

Driver170, on 01 May 2015 - 7:00 PM, said:

Also notice it doesn't say NA TEMP BELOW -XX

 

Because its already been cold temp corrected

That chart is an RNP

1 RNAV(GNSS) = RNP approach

2 RNAV(RNP)= RNP AR approach

 

So all 2 are RNP approaches

 

Or...

 

RNAV (GNSS) Approach (RNP APCH)

RNAV (RNP) Approach (RNP AR APCH)

 

but "scandinavian13" claims it is not (he has a valid point there explaining why)

http://forum.avsim.n...-2#entry3231030

 

 

that means relaying on the Title "RNAV (GNSS)" alone to determine rather it is an RNP or not is not sufficient.

that means the UK RNP publication you mentioned above is incorrect

 

Its all in the link that simon has posted

[Akila 39]

then how come "scandinavian13" insisted it is not an RNP Approach.

the Min' is also way behind 400ft as you guys claimed earlier...

 

also from the statement above (CAA) I understand that since it indicates LNAV only it is not RNP (Non-Precision).

 

LNAV approach operations are flown on Non-Precision RNAV(GNSS) procedures which are charted to a Minimum Descent Altitude (MDA).

 

the chart above is an LNAV only (not RNP) ,Also the Chart states "MDA" (non-precision).

However the chat's title is RNAV (GNSS) which suggests it is an RNP.

which one is the correct one?

 

Is there such thing as a non-precision RNP approach?

I thought RNP is all about precision.....