RNP Support with Navigraph 2204

[steku 22]

Navigraph announced today:

"We’re excited to announce that from AIRAC Cycle 2204 and onwards, the navdata provided by Navigraph supports RNP (Required Navigation Performance). (...) The Aerosoft CRJ is already compliant as of AIRAC Cycle 2204"

https://navigraph.com/blog/rnpsupport?utm_source=newsletter&utm_medium=email&utm_campaign=2204_2&utm_content=rnpsupport

 

What are the actual benefits for the CRJ pilots?

 

[Dopster198 131]

I was also a little bit confused by this, after reading in this same forum that the CRJ is not in fact capable of flying RNP approaches.

 

Maybe the FMC is in fact capable of dealing with the format, but the plane is not able to actually fly such approaches?

 

Perhaps I’m misinterpreting something.

[Thijs010 49]

Yes it is a very confusing message from Navigraph. Also for instance with the FlyByWire A320 I could already fly RNP approaches... so what's new in the update? And indeed the CRJ is not capable of flying these approaches I did read when it was released by Aerosoft 

[Aerosoft Team [Inactive Account] 51558]

I honestly do not know, will contact Navigraph.

[Richard Dastardly 108]

I don't know either - RNP approaches still appear in the FMS ( although I assume even if they're tagged by Navigraph they'd not be filtered out yet anyway ) and I flew a RNP AR approach ( without any VNAV, I don't have coupled VNAV on and I wouldn't know what to do with it anyway ).

 

Incidentally to add to the LNAV behaviour confusion, the -900 flew this perfectly - so perfectly that it didn't line up with the runway because the last WP is in the wrong place... ( or the runway is in the wrong place! ). I guess marginally cutting two WPs is out of the RNP spec? ( edit: flight instructor says a/c has to be RNP capable to fly an RNAV procedure - this is just LNAV. Nuances partially lost on me, must admit ).

 

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[Crabby 28]

According to my buddy who flew the CRJ for Envoy:

The CRJ is not AUTHORIZED to fly RNP approaches with CURVED segments like the one above.  This was explained to me to be due to the fixed bank angle used by the autopilot.  With a fixed bank angle the aircraft cannot compensate for wind changes during an approach like above and may not be able to maintain the RNP requirements for nav accuracy, listed on the chart and in most cases (all cases I have seen) needs be 0.3.  I think there was/is an available upgrade but that most operators have not adopted it due to cost.  Again, not my personal information and I don't know if the info is operator specific or plane specific. 

 

Now, what I have seen with the new Navigraph update, using both the data download for the CRJ and for MSFS itself.

1. I no longer see weird double segments on the ND display when selecting certain RNAV approaches.  By no longer I mean that I have flown 4 flights so far with the new AIRAC and have not seen it.  It was normal for me to see it about 40% of the time.  So I am encouraged.

2. DIR TO seems to work better.  Again, not many flights, but hey it's a start. 

[Richard Dastardly 108]

Yep, deliberately picked a RNP AR approach with curved segments ( and that was actually quite windy ) as something that our a/c should struggle with. I should probably have enabled VNAV to see if that worked too but as I said, don't know what I'm doing with it. I wonder what they did, be interesting to see what they tell Matthijs.

 

Edit: well, the 900 won't fly the usual ILS NDB approach to my local airport at all anymore - reliably sails straight across the ILS lobes & doesn't correct until far too late to pick up GS - so I'm not sure what they did, but I don't like it.