RNAV1 and RNP

Discussion in 'Cleared for the Approach' started by PilotRPI, Feb 3, 2019.

  1. PilotRPI

    PilotRPI Line Up and Wait

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    I found somewhere that WAAS GPS's are RNP 0.3. The plane I'm using for my checkride has a non-waas Garmin 430. KOLE has 3 approaches which mention the need for RNAV 1.0 or say RNP Approach. Can a non-waas Garmin 430 fly these approaches? The procedures do not say approval required, which is what I usually see for an RNP approach. I just can't find for certain that a non-waas is or is not RNP/RNAV-1.

    Thanks!
     
  2. MauleSkinner

    MauleSkinner Final Approach

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    I’m not seeing any mention of those requirements for any KOLE approaches. Where on the chart are you seeing them?
     
  3. Unit74

    Unit74 Final Approach

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    Last check, part 91 drivers were not authorized RNP procedures. You rocking an advanced AP, BARO nav capabilites and the letter of authorization in that bug smasher?
     
  4. asicer

    asicer En-Route

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    Not sure, but I think the OP is talking about this:
    Clipboard01.png
     
  5. Walboy

    Walboy Cleared for Takeoff

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    This spreadsheet from Garmin might be helpful.
     

    Attached Files:

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  6. RussR

    RussR Cleared for Takeoff

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    Note in the spreadsheet linked by @Walboy , the 430/530 non-W models are "yes" for both RNAV 1 and RNP APCH.

    The KOLE LOC RWY 22 is kind of a hybrid approach, since you need to use an RNAV unit to enter the procedure. This is because of the decommissioning (or pending decommissioning) of the ELZ VORTAC which previously provided a feeder into the procedure and the missed approach holding pattern. Since there is no other suitable NAVAID nearby, RNAV is required, to the RNAV-1 "NavSpec". Your 430 meets this.

    This of course creates an unusual situation, since if you have an RNAV unit, it is probably also able to conduct RNAV (GPS) approaches at least to the LNAV minima, in which case you'd just fly the RNAV (GPS) RWY 22, which actually has a 20 foot lower MDA. I suppose this is for the corner cases of an RNAV unit that is not approach-approved.

    The RNAV procedures at the OLE require "RNP APCH" capability. This is the new terminology for what we've been doing all along. Yes, your 430 can do these.

    Blog post here, starting about 2/3 of the way down I talk about RNP APCH:
    http://cfiruss.blogspot.com/2018/05/goodbye-dme-hello-equipment.html
     
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  7. Walboy

    Walboy Cleared for Takeoff

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    I really wish this subject was dealt with in an easier to understand way in the AIM and Instrument Procedures handbook. It seems to be needlessly confusing.

    Maybe some of the members here who know the powers that be can mention this.

    @RussR 's explanation in the link he provided is the clearest I've seen so far. Maybe you can moonlight writing manuals for the FAA. Haha.
     
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  8. MauleSkinner

    MauleSkinner Final Approach

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    +1 on Russ' article...the changes being made to RNAV(GPS) terminology is going to make things more confusing for a while.
     
    Last edited: Feb 3, 2019
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  9. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    Is it possible for a gps to have approaches (or other procedures) in it, for which it is not legal to fly because of the limitations of that same device?
     
  10. Tspin

    Tspin Pre-Flight

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    Yes. A non-WASS GPS can be used to fly an approach to LNAV minimums, but not to LPV minimums. These minimums can be on the same approach.
     
  11. PilotRPI

    PilotRPI Line Up and Wait

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    Thank you. I ended up finding this as well in an AOPA article. Took over an hour of my life looking for something this simple. Just had to pick the perfect words for Google to find it.

    AIM and FAA pubs make stuff like this so difficult. AIM should sinply sat something like to check with manuf for RNP applicability categories.

    This article is good in that it discusses the format changes to plates as well as expected combinations of rnav and radio based procedures to come.

    https://www.aopa.org/advocacy/airpo...n-and-charting/instrument-approach-procedures
     
  12. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    Thanks
    How about rnav sids/stars for which the device does not have the required rnp? Would you find those in the database, and will it allow you to fly them?
     
  13. MauleSkinner

    MauleSkinner Final Approach

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    You shouldn’t find anything there that the box can’t fly...you may, however, find some procedures that are operator-specific, but you won’t have charts for those, so you wouldn’t be able to fly them anyway.
     
  14. WeekendWarrior

    WeekendWarrior Filing Flight Plan

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    The whole "RNP APCH" thing is something new as of mid-2018, called the PBN Box. Performance Based Navigation. Eventually, you'll start seeing that on most all RNAV procedures. You'll also start seeing more specific RNAV requirements. Along with PBN for RNAV approaches, a similar box is being added in the same location of traditional ground-based approaches listing required equipments. It gets confusing when you have multiple chart notes in multiple places that specify things like "ADF Required", etc. The intent of the new boxes is to simplify equipment requirement notes and consolidate them to one standard location.

    The confusion seems to come from the choice of letters, RNP. RNP, or Required Navigational Performance, is nothing more than a spec of how precise the GPS is. Where the confusion comes is in the naming - currently, the FAA names "general" RNAV procedures "RNAV (GPS) Rwy xx". Those are procedures that bug-smashers like us in the 91 world can fly. "RNAV (RNP) Rwy xx" procedures are limited to operators who have specific authorization to use them, generally via an OpSpec or LOA. We call them RNP-AR approaches - authorization required. They require fancier hardware and training. A lot of those procedures will contain things like RF, or Radius-to-Fix legs, and other fun elements that a majority of GA GPS units cannot fly. The GTNs do have the ability to fly RF legs after a certain software update, but I don't believe there are any non-AR approaches with RF in the US NAS. Bottom line - you shouldn't ever see a procedure in your GPS that you won't be able to fly. Just know the line(s) of minima that you can use, and choose your DA/MDA based on that. Non-WAAS limits you to LNAV minima, while WAAS opens up LP and LPV. In some cases, the LPV minima will be as low as 200', which match most standard Cat I ILS minima.

    Almost all applicable RNAV procedures that have been amended since, I believe, AIRAC 1806, have had this added. It doesn't mean too much to the average 91 pilot, as long as you have a suitable approach-capable GPS unit. The link posted earlier helps explain it. A non-WAAS 430/530 will still allow you to fly the approaches, but only to the LNAV MDA minima. Newer units like the 430W (W being the abbreviation for WAAS) and the GTN series will allow you to fly down to the lowest minima published as long as GPS integrity is maintained. If the unit loses the required number of satellites during the approach, it will display some sort of RAIM loss annunciation and/or display LNAV annunciations, depending on the unit.
     
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  15. MauleSkinner

    MauleSkinner Final Approach

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    There is, however, a non-AR SID with RF legs out of KSNA...the STAYY 1 uses RF legs to approximate flying over the river to the coast.

    https://aeronav.faa.gov/d-tpp/1902/00377STAYY.PDF
     
  16. RussR

    RussR Cleared for Takeoff

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    There is one that I know of - KCRQ RNAV (GPS) X RWY 24

    https://skyvector.com/files/tpp/1902/pdf/05310RX24.PDF
     
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  17. WeekendWarrior

    WeekendWarrior Filing Flight Plan

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    I suspected there were a few, but I haven't come across them as of yet. Good to know. I believe we will start seeing more of them over time, but for the time being, there may only be a few out there, this being one
     
  18. aterpster

    aterpster Pattern Altitude

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    Russ is doing what the FAA should be doing.
     
  19. aterpster

    aterpster Pattern Altitude

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  20. aterpster

    aterpster Pattern Altitude

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  21. aterpster

    aterpster Pattern Altitude

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    Great work, Russ!

    "RNP APCH" replacing "DME/DME RNP-0.3 NA" probably will create a new set of confusions for those old RNAV birds that were made before GPS, such as a lot of 767s and early ABs. (Sure there are others I don't know about.) The old note was quite clear for those operators. Not so with "RNP APCH." And, some of those old 767s are now being operated Part 135 rather than 121, so the training is not as concise.
     
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