Bob,
Can you tell me what the difference is between an RNAV and RNAV-Y approach please?

About 10 to 20% of the RNAV approaches in the DAPs are listed as RNAV approaches and the majority are RNAV-Y approaches. I've spent hours googling this and cannot find an answer. There are lots of sites that talk about the difference between RNAV-Z and RNAV-Y, but none that mention RNAV vs RNAV-Y.

I was also intrigued as to why Air Services Australia labels circling only RNAV approaches by the N, E, S or W quadrant the approach comes from rather than following their convention of labeling other circling only NDB or VOR approaches as "A" as in NDB-A.

I was further intrigued again when I found VOR-Z Rwy 03 at YCFS, but no VOR-Y. Is there any reason to use the Z identifier when there is only one VOR approach to Rwy 03?

Happy New Year,

Joe Luxford

Hi Joe,
You can find some of your answers from the infomation pages in the DAP. I have attached the link below.
As it explains, it is to say that there are differences between the approaches to the same runway. For example, YMAV RWY 18 ILS uses either AV DME for ILS-Y or IAV DME for ILS-Z.

For the RNAV approaches, the prefix letter indicates the direction the approach is coming from. North, South, East and West.

To answer your question about YCFS only having a VOR-Z approach. It used to a VOR-Y some years ago which has probably been scrapped. The main differences were that Y was for Cat A & B aircraft only with a higher S-I minima and Z has a S-I from 12nm CFS DME published.
www.airservicesaustralia.com/aip/current/dap/GINNO04-137.pdf

Hope this all helps.

Cheers,

Mister W.

Thanks for the comments, but my original question still remains: what is the difference between the RNAV and RNAV-Z approaches in the DAPs?

I said RNAV-Y in my original question: it should have been RNAV-Z.

About 20% of the approaches in the DAP are RNAV and the other 80% are RNAV-Z. There are RNAV-Y approaches (curved RNP ones) at Norfolk Island.

From what I can gather there is no difference between the two and RNAV-Z is how they prefix the new charts. All the old RNAV charts are being called RNAV-Z after being re-validated. If you look at the currency date you will see the RNAV charts are about 4 years old. 10-20% of charts being RNAV only sounds about right. They will all be RNAV-Z by the end of the year. I have an old YBLT RNAV plates at home and it's the same as the RNAV-Z in the latest ammendment.

Another reason is for the programming of the FMC database. Because there are so many different approaches the FMC is looking for RNAV-dash-something to entered.



Cheers,

Mister W

Thanks for that. I checked some of the ADs that were listed as RNAV in my 2013 DAPs and they are now RNAV-Z in the latest plates in AvPlan - and showing PROC NAME in the list of changes at the bottom of the plate.

There seems to be widespread uncertainty about this area. Judging by the obscure reference in the AIP I doubt if anyone in CASA has much of a clue either! There are many cases in the DAP where the sole ILS, NDB, VOR or RNAV approach to a particular runway still contains the Z, Y, A, or B suffix. I have asked a few test officers about it and they are always very evasive in their answers. I am currently doing further research into this and I'll let you know if anything useful turns up.

Bob