RNAV Approach & TAA

Discussion in 'Pilot Training' started by RocktheWings, Mar 1, 2021.

  1. MauleSkinner

    MauleSkinner Final Approach

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    “Established on course” being distinctly different from “established on a published portion of the approach”.
     
  2. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    I really like these discussions! I have always thought the correct “until established” procedure was what David has been describing not just inside the TAA. Obviously this is not clear to all as to which is proper. And since no response yet from one of our several members of ATC I can’t help but wonder if it is a bit too loosely understood. Until someone from ATC clears this up I will take the more conservative action of “until established” means on the inbound leg with the needle(s) indicating proper proximity to the inbound route for a stabilized direction towards the runway.:popcorn:
     
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  3. luvflyin

    luvflyin Final Approach PoA Supporter

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    Established on ‘what’? There ain’t no ATC phraseology that is just ‘until established.’ It is always qualified somehow. Until established on [localizer, airway, radial, course to, bearing from, etc]. If just ‘until established’ is all the Controller said in the original post, then this is just a case of sloppy work by the Controller. @LesGawlik ’s example in post #8 is right out of the Controllers Handbook, 7110.65.
    Pertinent here also is the PC/G definition of TAA that @RussR quoted in post #33. Maybe they could go a little farther with that and say a TAA is a ‘segment’ of an Approach in addition to ‘published portions.’ In the original post @RocktheWings was already in the TAA. The Controller getting all untilestablishy, especially doing it incorrectly, just confused things. The correct clearance would have been simply ‘cleared for the approach.’
     
    Last edited: Mar 2, 2021
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  4. Deelee

    Deelee Cleared for Takeoff

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    Probably would have simply asked for clarification in this case. You are cleared for the RNAV XXX which includes a TAA, so you can descend as low as the altitude marked in your sector of the TAA. The maintain 3000 until established part is a bit confusing. If it were me, I would have asked, "please advise is N1234R authorized to descend to the charted TAA altitude or would you like me at 3 until (specify which leg here....)?"

    Just sayin. One of the things I have learned about flying IFR in the system is - if you are confused about something, don't hesitate to ask. In my (limited) experience, my requests for clarification have always been met with a clarification in a tone from the controller that seems appreciative. Never irritated. Never upset. Honestly, I wouldn't care if I upset someone by asking to clarify. Rather me and the controller be in sync on the instruction than I get a pilot deviation or worse - metal plate a hillside. I don't know this for sure, but it seems as thought he controllers appreciate pilots asking to confirm when instructions can be ambiguous.
     
  5. flyingron

    flyingron Touchdown! Greaser! PoA Supporter

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    Note that TAAs aren't limited to RNAV approaches. We have one on an ILS here.
     
  6. luvflyin

    luvflyin Final Approach PoA Supporter

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    What Approach is that? I’ve seen ILS Approaches that require RNAV. Needed for initial and intermediate segments, but not with TAA’s
     
  7. flyingron

    flyingron Touchdown! Greaser! PoA Supporter

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    Statesville (SVH) NC ILS or LOC Y RWY 23. You need the GPS for the TAA, but after you get to the center of the TAA (PEGTE, which is the intersection of the CLT 025 radial and the localizer), you only need the LOC.
    This is a fortunate addition as the old approach (now the Z version) has an IAF which is out in GSO's airspace. You never got that but rather vectors to final around PEGTE somewhere anyhow.

    I'm not sure why you need the GPS for the TAA other than some odd TERPS thing and you'd be hard pressed to determine the distance from PEGTE without it an old fashioned rho-theta RNAV.


    https://aeronav.faa.gov/d-tpp/2102/05683IYLY28.PDF
     
  8. RussR

    RussR Pattern Altitude

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    How would you navigate direct to PEGTE without GPS? I don't view that as an "odd TERPS thing".

    Unless you're asking about non-GPS forms of RNAV, but one of those, DME/DME/IRU, requires an evaluation of the DME station geometry (so I guess that could be an "odd TERPS thing"), and the other, VOR/DME RNAV, while there are still rules in TERPS for that, it is all but phased out with zero of those type of approaches left in the U.S.
     
  9. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    I called the local FISDO in Lincoln for a clarification. The individual I spoke with gave me his thoughts as follows and is my interpretation of the conversation:

    Just being inside the TAA does NOT constitute established! To be established it is expected that you have no more than 1/2 needle deflection. This may be a GPS indication on a RNAV approach at the IAF on the T segment of the approach. Or for a ILS or VOR approach definitely on the inbound leg with less than 1/2 needle deflection and inside the plate distance requirement. But on the outbound leg and during the procedure turn when the needle deflection exceeds 1/2 is definitely a gray area of being established and until better defined is not something recommended.

    I have not shot a VOR approach in actual for a long time but there is an ILS approach at GRI that I occasionally use without radar vectors and I am not going to an altitude below an instruction for until established until I am inbound with needles inside 1/2 deflection.
     
  10. MauleSkinner

    MauleSkinner Final Approach

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    So he’s saying that a TAA is not an operational altitude, but is exactly the same as an MSA, contrary to the AIM and IPH guidance.
     
  11. EdFred

    EdFred Taxi to Parking

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    Well the Memphis FSDO also said that GPS couldn't be used to identify an NDB, so not surprising.
     
  12. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    He is saying that being inside the TAA by itself does not constitute being established on an approach, more simply to be established you have to have at least 1/2 needle deflection on your Navigation source for the approach. Again this was my interpretation but that seems pretty straight forward to me and what I would expect. Surprised me that it also included the T leg between an RNAV IAF and the final course leg to the runway.
     
  13. MauleSkinner

    MauleSkinner Final Approach

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    What navigation source for the approach extends beyond (prior to) the IAF but doesn’t have its own altitude to start with?
     
  14. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    I am missing your point? Regardless of the navigation source ATC can assign an altitude above the minimum and specify an altitude not to be left from "until established". Which means to me you can't descend from that assigned altitude until the IAF is reached and a maximum 1/2 deflection of the needle. This is more generous than what I originally thought as I had previously felt you had to be inbound and on the final course heading. And I think is also what David was implying. What am I missing?
     
  15. MauleSkinner

    MauleSkinner Final Approach

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    That interpretation makes TAAs no different than MSAs. The FAA documentation specifically says they’re different.
     
  16. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    So do you think the gentleman I spoke with at FISDO is incorrect? How would you word the "until established" on the approach definition differently.
     
  17. MauleSkinner

    MauleSkinner Final Approach

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    Yes.

    “Established on a published portion of the approach” is within the TAA area and cleared for the approach, which is distinctly different from “established on course”, which would be the definition you got from the FSDO.
     
  18. RussR

    RussR Pattern Altitude

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    Yes, I think the FSDO is incorrect. From your description of the conversation, it sounds like the FSDO person may never have flown a TAA or a GPS approach, for that matter. Experience levels do vary. If he really said "you have to be within half-scale (first of all, that's not defined anywhere either so it is apparently his opinion), does he not realize that within the TAA, when you go direct to the IAF, the CDI is immediately centered?

    So if the test is just "must be within half-scale", and you are within the TAA, and cleared direct to the IAF like normal, then yes you are within half scale and therefore by his test, "established".
     
  19. RussR

    RussR Pattern Altitude

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    From the 7110.65Y, 4-8-1j
    1. Aircraft that are within the lateral boundary of a TAA, and at or above the TAA minimum altitude, are established on the approach and may be issued an approach clearance without an altitude restriction.

    There are several examples of proper terminology in this situation, none of them use the words "maintain XXXX until established".

    We tend to think of ATC as some kind of robot that always gets everything right and uses the correct phraseology. But here's the thing. Any approach controller (maybe not center controllers) will be saying the words "maintain XXXX until established" about eleventy thousand times a day to aircraft on vectors to an ILS or RNAV approach. Then randomly one airplane pops up requesting an approach to another airport, that has a TAA. It's pretty reasonable to see that they might say the exact same words they've said thousand of times already, even if they are not quite correct. Especially since nobody is likely to question them - so it worked that one time today, it'll probably work next week, and the next time.
     
  20. Clip4

    Clip4 Final Approach

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    The question was not asked properly, so he got a wrong response.
     
  21. David Megginson

    David Megginson Cleared for Takeoff

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    Agreed -- this has been a great discussion.

    We don't have a definitive answer yet, but I've at least learned that it's not as cut-and-dry as I assumed when I posted the first response to the thread. The best answer I've seen was in another forum that picked up on the discussion — because the language was unclear, ask the controller what they mean. That's always good advice — as we've seen here, experienced IFR pilots have come up with opposite interpretations.

    On the other forum, one poster mentioned seeing the lights of another plane zoom by just 200 ft removed in altitude in a busy terminal area because someone involved had misinterpreted a similar instruction, so it's more important to be safe than to be "right". Armchair lawyering like we've all been involved in here (including me) is best confined to actual armchairs, not the cockpit.
     
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  22. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    You may be correct, I honestly do not know. I received my instrument rating 50 years go before anyone had heard of GPS equipment. Thought I had this figured out but you are certainly putting a doubt in my mind? I would not consider being established on the approach until after passing the IAF. So centering the needle by going direct to the IAF would be premature in my mind as established on the approach. And if you have been cleared to a specific IAF then after passing the IAF hitting direct & enter would not be OK in my mind? The approach should have been loaded and followed from the IAF.
     
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  23. EdFred

    EdFred Taxi to Parking

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    There a list of airports with TAA? All the approaches I picked around here locally just have the MSA circle.

    Edit, finally found 1 airport with them.
     
  24. David Megginson

    David Megginson Cleared for Takeoff

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    I'm on the same page as you (except I'd consider "established" to be on the centreline of any regular approach segment, not necessarily past the FAF), but I realise that many others are reading it differently, so I have a doubt in my mind now as well.
     
  25. luvflyin

    luvflyin Final Approach PoA Supporter

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    You certainly wouldn’t go direct enter after passing the IAF/IF. I think you may be responding to a post I put up and then deleted after thinking about it. If that’s what you responded to about the direct enter enter it was just to illustrate the point that @RussR had made in post #58. That when you’ve been cleared to the IAF/IF from out yonder, you will have a Track to follow that you can get off of by a half of a deflection from. My ‘quip’ about if you do, just hit direct enter enter and you’ll be back on again, should not be done. They cleared you direct and expect you to do so. Not meander around within the TAA chasing a Needle you keep changing.
     
  26. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    Yes you are correct, the response was a result of the deleted post.
     
  27. flyingron

    flyingron Touchdown! Greaser! PoA Supporter

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    Same way you do for the Z approach which doesn't require GPS. If you come in from the east side, you can skip the Hold-in-loo with the Y approach that you're obliged to do on the Z.

    My comment about the rho-theta RNAV was just that it would be hard to tell if you're in the TAA (30 miles or whatever) without either GPS or some other way to measure distance from PEGTE.
     
  28. RussR

    RussR Pattern Altitude

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    But the route from GSO to PEGTE using the GSO radial is not published on the Y. As far as being cleared for the Y, that routing does not exist and would not be a valid segment.

    If you're asking "why is there a Y and a Z to begin with", well that's a good question, but a different question. But "why is GPS required for the TAA on the Y" is just because there's no other way to navigate direct to a fix.
     
  29. pburger

    pburger Pre-takeoff checklist

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    Asked and answered.

    (I honestly thought "established" meant "established on a published approach segment" which would mean on an actual bold line shown on the approach plate. But RussR's reference clearly shows that being within the TAA is considered "established on the approach". I try to learn something new everyday, and in this case, I did.)
     
  30. Briar Rabbit

    Briar Rabbit Line Up and Wait

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    I did as well! The old dog new trick theory with some effort and help from friends at POA. Thanks
     
  31. Craigd31

    Craigd31 Pre-Flight

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    Consider the "or IAP" and the example that includes the verbiage "established on the final approach course" that is part of the same paragraph....but interpret it however you want.
     
  32. MauleSkinner

    MauleSkinner Final Approach

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    Considered again. No change.
     
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  33. flyingron

    flyingron Touchdown! Greaser! PoA Supporter

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    That just means you can't be considered on the approach at that point, not that it's not a valid means of navigation
    Well, the Z was there first (for all the time I've been flying down here). It's still the only approach if you don't have a GPS.
    As I pointed out, that the Y gives you the option of getting cleared to PEGTE without the hold-in-loo, something that didn't happen before without radar vectors (in fact, I've never not gotten radar vectors to just outside of PEGTE when I've had to fly that approach.
    Eh? There are tons of approaches with IAFs not on a navaid or airway. They don't have GPS required. Operationally, the only real reason is I can't see any way of determining you're WITHIN the TAA without it. The fact appears that the FAA has designated a TAA as an RNAV procedure regardless of what the nature of the fix in the middle of it is. It's an RNAV segment regardless of the underlying approach.
     
  34. RussR

    RussR Pattern Altitude

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    You can't mix and match different procedures. That radial is not published on the Y, therefore it's not a segment of the approach, nor is it approved for use on that procedure. If you want to use that radial, fly the Z. Additionally, if the GSO VOR goes down, or that radial becomes unusable, there will be no NOTAM issued against the Y, because it's not part of that procedure.

    True for IAFs. But then they should have a feeder route from a NAVAID or airway. And if not, then they should be labeled "RADAR Required" either in the planview (old style) or in the equipment requirements box (new style). Most ILS approaches at major airports are exactly like this - they start at an IF (not an IAF) and have RADAR Required. The whole reason for RADAR Required is that otherwise, the aircraft cannot self-navigate to the procedure (aircraft are not assumed to have GPS or any other form of RNAV on a ILS/VOR/NDB approach, unless specifically stated as a requirement.)
     
  35. John Collins

    John Collins Pattern Altitude

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    A perfect example of why calling the local FSDO is not always a useful idea. All you get is one more opinion and they are frequently wrong as in this case. FSDO does not speak for the FAA on these matters. You won't find any definition of what constitutes being established in any of the FAA guidance with two exceptions, there is a "Definition of “established” for RNAV and RNP operations" in the AIM, 5−5−16 RNAV and RNP Operations, a. Pilot, section 11 and in the instrument ACS which only applies to the practical test. There was a set of proposed wording that was offered by FAA HQ that defined what established means, but it never made it into guidance. BTW, there are many ILS now published that use a TAA, for example my airport at KUZA, Rock Hill, SC has an ILS or LOC Y Rwy 2 which uses a TAA and the ILS or LOC Z Rwy 2 which uses conventional navigation to join the localizer.

    If an aircraft is inside a TAA and at or above the charted TAA segment altitude, it is established. Just because one is established does not mean that the controller can't restrict the altitude, but if they don't restrict the altitude, a clearance for the approach is also a clearance to descend to the TAA altitude. However, the clearance will be different if there is an altitude restriction as the fix that the altitude is to be maintained will be specified in the clearance as a crossing restriction. The OP wrote: "ATC states "maintain 3000 until established, cleared for RNAV etc". This is non standard phraseology. If they intended the aircraft to maintain 3000 until a specific IAF, the phraseology would be is "Cross [fix name] at or above three thousand, cleared R−NAV Runway One Eight Approach." Since the OP clearance is confusing, you should clarify the meaning with the controller.


    Here are the two paragraphs that apply that is the guidance given to controllers from FAA order 7110.65:

     
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