LPV is it precison or non-precision

Discussion in 'Cleared for the Approach' started by Areeda, Jun 16, 2007.

  1. Areeda

    Areeda Pattern Altitude

    Joined:
    Aug 21, 2005
    Messages:
    2,189
    Location:
    Los Angeles, CA
    Display Name:

    Display name:
    Areeda
  2. Fast n' Furious

    Fast n' Furious Line Up and Wait

    Joined:
    Mar 4, 2005
    Messages:
    580
    Location:
    WI
    Display Name:

    Display name:
    iJustLanded
    That darn ICAO.......

    http://www.faa.gov/about/office_org...policies_guidance/tils/media/TIL03-048att.pdf

    Annex 10 to ICAO drives the definition of what is and what isn't a Precision Approach. As a signatory to ICAO, we have to play along. Given that the majority of the ICAO states went a different way with space based NAV (preferring to focus on the enroute rather than the terminal) it's no wonder that there might be some resistance to updating the definition shown in ICAO Annex 10.
     
    Last edited: Jun 17, 2007
  3. gismo

    gismo Touchdown! Greaser!

    Joined:
    Feb 28, 2005
    Messages:
    12,676
    Location:
    Minneapolis
    Display Name:

    Display name:
    iGismo
    The official FAA position is that LPV is not a precision approach. Apparently it takes more than vertical guidance to make one. AFaIK if and when LAAS becomes a reality, those approaches will be considered precision. The only effect this has on anything I can think of is for an IR checkride and for the weather requirements to list an airport as an IFR alternate.
     
  4. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,482
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
  5. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    Can you point to a source document for that?
     
  6. cherokeeflyboy

    cherokeeflyboy Line Up and Wait

    Joined:
    Mar 6, 2005
    Messages:
    719
    Display Name:

    Display name:
    Cherokeeflyboy
  7. Areeda

    Areeda Pattern Altitude

    Joined:
    Aug 21, 2005
    Messages:
    2,189
    Location:
    Los Angeles, CA
    Display Name:

    Display name:
    Areeda
    This is my problem. The only approaches defined as precision were the ILS and PAR and GLS. APV is in a different class.

    The reason for my question is to define the minimum necessary for an IPC in a WAAS enabled aircraft to meet the PTS requirements.

    I use the minimum to allow the people who really don't need an IPC to prove it as quickly (cheaply) as possible. We can do this in about 1.0 if ATC isn't too busy.

    I'm coming to the conclusion that I should add the LPV approach rather than substitute it for one of the others.

    Thanks for the discussion.

    Joe
     
    Last edited: Jun 17, 2007
  8. ghogue

    ghogue Pre-takeoff checklist

    Joined:
    Sep 15, 2006
    Messages:
    118
    Location:
    Smyrna, TN
    Display Name:

    Display name:
    ghogue

    Ron,
    I agree with Lance on this. Not long ago I read a document from FAA that said an LPV did not meet the lateral accuracy to meet precision requirements (yet). I can't remember where it is, but I'm looking and will post it when I locate it. I thought I had saved it on my computer, but haven't found it yet. I don't expect anybody to just take my word for this without documentation, but I suspect what I'm looking for is also what Lance was referring to.
     
  9. gismo

    gismo Touchdown! Greaser!

    Joined:
    Feb 28, 2005
    Messages:
    12,676
    Location:
    Minneapolis
    Display Name:

    Display name:
    iGismo
    I think we saw the same thing. What I'm remembering was from the FAA and the only thing I'm sure of is that it clearly stated that for flight plan alternate's, LPVs require non-precision weather mins (800/2). I believe the document I saw was in the form of a letter answering a question.
     
  10. ghogue

    ghogue Pre-takeoff checklist

    Joined:
    Sep 15, 2006
    Messages:
    118
    Location:
    Smyrna, TN
    Display Name:

    Display name:
    ghogue
    Well, I feel rather ignorant. The document I was referring to and couldn't find was the AIM. As posted earlier by Areeda it says:

    AIM 5-4-5(a)(7)

    (b) Approach with Vertical Guidance (APV). An instrument approach based on a navigation system that is not required to meet the precision approach standards of ICAO Annex 10 but provides course and glidepath deviation information. For example, Baro-VNAV, LDA with glidepath, LNAV/VNAV and LPV are APV approaches.

    And AIM 1-1-20. Wide Area Augmentation System (WAAS)

    b. Instrument Approach Capabilities

    1. A new class of approach procedures which provide vertical guidance, but which do not meet the ICAO Annex 10 requirements for precision approaches has been developed to support satellite navigation use for aviation applications worldwide. These new procedures called Approach with Vertical Guidance (APV), are defined in ICAO Annex 6, and include approaches such as the LNAV/VNAV procedures presently being flown with barometric vertical navigation (Baro-VNAV). These approaches provide vertical guidance, but do not meet the more stringent standards of a precision approach. Properly certified WAAS receivers will be able to fly these LNAV/VNAV procedures using a WAAS electronic glide path, which eliminates the errors that can be introduced by using Barometric altimetery.
     
    Last edited: Jun 17, 2007
  11. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,482
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    I do believe to meet the criterion of an IPC, you won't be able to substitute the LPV for the ILS (or other PA) and meet the letter of the law. For all intents and purposes of practical demonstration of ability though, I don't see it making a rat's a$$ of a difference. Same indicator operating in the same fashion, the only difference is the precission of the indicator. I think this is another example of when technology out paces rule revision. You might consider pointing this out to the FAA for next years revision.
     
  12. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    Interesting -- so now there are three types of approaches: precision, APV, and nonprecision. Guess we have to wait for the IR PTS to catch up with that.
     
  13. ghogue

    ghogue Pre-takeoff checklist

    Joined:
    Sep 15, 2006
    Messages:
    118
    Location:
    Smyrna, TN
    Display Name:

    Display name:
    ghogue
    Lance,
    Is this what you were referring to? The info is in AIM (see below).

    1-1-20. Wide Area Augmentation System (WAAS)
    Para c.7.(a)
    (a) Due to initial system limitation, there are certain restrictions on WAAS operations. Pilots may plan to use any instrument approach authorized for use with WAAS avionics at a required alternate. However, when using WAAS at an alternate airport, flight planning must be based on flying the RNAV (GPS) LNAV minima line, or minima on a GPS approach procedure, or conventional approach procedure with "or GPS" in the title. Code of Federal Regulation (CFR) Part 91 nonprecision weather requirements must be used for planning. Upon arrival at an alternate, when the WAAS navigation system indicates that LNAV/VNAV or LPV service is available, then vertical guidance may be used to complete the approach using the displayed level of service. The FAA has begun removing the [​IMG] NA (Alternate Minimums Not Authorized) symbol from select RNAV (GPS) and GPS approach procedures so they may be used by approach approved WAAS receivers at alternate airports. Some approach procedures will still require the [​IMG] NA for other reasons, such as no weather reporting, so it cannot be removed from all procedures. Since every procedure must be individually evaluated, removal of the [​IMG] NA from RNAV (GPS) and GPS procedures will take some time.


    gary
     
  14. nosehair

    nosehair Cleared for Takeoff

    Joined:
    Jan 4, 2007
    Messages:
    1,011
    Location:
    Myrtle Beach
    Display Name:

    Display name:
    nosehair
    :rofl: :rofl: :rofl: :rofl:
     
  15. gismo

    gismo Touchdown! Greaser!

    Joined:
    Feb 28, 2005
    Messages:
    12,676
    Location:
    Minneapolis
    Display Name:

    Display name:
    iGismo
    I'm pretty sure the document I saw was in the form of a letter from the FAA chief counsel's office and I believe it said specifically that LPV and LNAV/VNAV were not considered to be precision approaches and therefore required the forecast to meet the standard for non-precision approaches if you wanted to list it as an alternate on an IFR flight plan. IIRC it also stated that when they became available (some) LAAS approaches would be treated as precision types.
     
  16. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    My remark earlier referred to the fact that the IR PTS requires two nonprecision and one precision approach, with no reference to APV's. Does that mean you have to turn the VNAV or LPV off if you fly a GPS approach with a WAAS GPS or it doesn't count since APV is neither precision nor nonprecision? And if it does count, since it requires vertical nav tracking, would it not adequately demonstrate your ability to fly a two-needle approach, especially if there was an APV approach around but not a convenient ILS for the practical test?

    As I said, the FAA needs to keep all its pubs up to date and consistent, and in this case, it has not.
     
  17. ghogue

    ghogue Pre-takeoff checklist

    Joined:
    Sep 15, 2006
    Messages:
    118
    Location:
    Smyrna, TN
    Display Name:

    Display name:
    ghogue
    Lance,
    I thought we had perhaps read the same document, but after re-looking at the AIM, I'm pretty sure that's what I was remembering. I did find this statement in AIM 1-1-20. Wide Area Augmentation System (WAAS):

    a. General
    1. The FAA developed the Wide Area Augmentation System (WAAS) to improve the accuracy, integrity and availability of GPS signals. WAAS will allow GPS to be used, as the aviation navigation system, from takeoff through Category I precision approach when it is complete. WAAS is a critical component of the FAA's strategic objective for a seamless satellite navigation system for civil aviation, improving capacity and safety.

    gary
     
  18. joemurffy

    joemurffy Filing Flight Plan

    Joined:
    Jan 25, 2008
    Messages:
    15
    Location:
    SW Iowa
    Display Name:

    Display name:
    Joe Murphy
    Was looking for the statement that if you have WAAS, you don't need to meet the requirement of choosing an alternate airport that has something other than GPS approaches. Still haven't found it specifically stated that way, but since WAAS is allowable as single-source navigation, it makes sense - as long as you only plan on using the LNAV altitudes.

    Okay, back on the post's topic. The original question of whether or not an LPV approach is to be considered a precision approach was answered - it is not. But it is also not a non-precision approach, but an approach with vertical guidance. So, what should you use as your standard alternate minimums in this case? Here are the answers and references I found one day in looking for all of this. I cut this from a post I made elsewhere. For those of you who think that the FAR/AIM is the beat-all, end-all of the rules, good luck with that. :)


    Concerning the construction and use of instrument approaches, here is what I've learned and what I've confirmed:

    - There are three types of instrument approach procedures (AIM, 5-4-5, 7):
    o Precision Approaches
    o Nonprecision Approaches
    o Approaches with Vertical Guidance (APV)

    - Approaches with Vertical Guidance are considered semi-precision and nonprecision in their accuracy
    o FAA-H-8261-1A, pg 5-5

    - Approaches with Vertical Guidance shall use 800ft/2sm for the standard alternate minimums.
    o FAA-H-8261-1A, pg 5-5
    o FAA Order 8260.3B Chg 20, Table 3-12

    - Although WAAS LPV approaches are not considered precision, the groundwork is laid to classify them as precision once LAAS comes online.
    o FAA-H-8261-1A, pg 5-49,50
    o AC 150/5300-13 Chg 6, Appendix 16

    Baro-VNAV, LDA with glidepath, LNAV/VNAV and LPV are all Approaches with Vertical Guidance. Concerning the definition of precision and nonprecision IAPs, I just don't think that they have caught up with the times by strictly tying them to the existance of a glideslope/glidepath.
     
  19. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    800-2.
     
  20. bobmrg

    bobmrg En-Route

    Joined:
    Aug 13, 2007
    Messages:
    2,864
    Display Name:

    Display name:
    Bob Gardner
    In the Introduction to the proposed new instrument PTS it is made clear that there are no satellite-based precision approaches.

    Bob Gardner
     
  21. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    I would point out that the FAA has, in the two years since I asked that question, provided better guidance in the AIM and other documents.
     
  22. gismo

    gismo Touchdown! Greaser!

    Joined:
    Feb 28, 2005
    Messages:
    12,676
    Location:
    Minneapolis
    Display Name:

    Display name:
    iGismo
    Since we're resurrecting the dead here, I thought I'd add that I dug this out of my latest copy of the Instrument Procedures Handbook Chapter 5 the information that the new third type of approach is apparently called a "semi-precision" approach:

     
  23. Dave Siciliano

    Dave Siciliano Final Approach

    Joined:
    Feb 27, 2005
    Messages:
    6,438
    Location:
    Dallas, Texas
    Display Name:

    Display name:
    Dave Siciliano
    In the 2007 instrument Procedures Handbook at 5-42 top left:

    There are three types of procedures based on the final approach course guidance:
    Precision Approach (PA)-an instrument approach based on a navigation system that provides course and glidepath deviation information meeting precision standards. Precision Approach Radar (PAR). ILS, and Microwave Landing System (MLS) procedures are examples of PA procedures.

    Approach with Vertical Guidance (APV) - an instrument approach based on a navigation system that is not required to meet the precision approach standards but provides course and glidepath deviation information. Baro-VNAV, LSA with glidepath and LPV are examples of APV approaches.

    Nonprecision Approach (NPA).....

    Best,

    Dave
     
  24. KennyFlys

    KennyFlys Guest

    "semi-precision"?

    How do those measure up in a flight check with a "precision" approach?
     
  25. TangoWhiskey

    TangoWhiskey Touchdown! Greaser!

    Joined:
    Feb 23, 2005
    Messages:
    14,209
    Location:
    Midlothian, TX
    Display Name:

    Display name:
    3Green
  26. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    If by "flight check" you mean an instrument practical test or IPC, they don't. Gotta be an ILS unless you have one of the two airplanes in the US equipped with MLS and you're at one of the two airports in the US with MLS approaches.
     
  27. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    As noted above, in the two years since I asked that question, several FAA publications have provided that answer, and the issue is no longer in question as it was two years ago.
     
  28. TMetzinger

    TMetzinger Final Approach

    Joined:
    Mar 6, 2006
    Messages:
    9,885
    Location:
    Northern Virginia
    Display Name:

    Display name:
    Tim
    Where in the definition of "non-precision" is vertical guidance excluded? I'd suggest that all the APVs are non-precision (though much cooler) until the FAA specifically calls any of them "precision".
     
  29. TangoWhiskey

    TangoWhiskey Touchdown! Greaser!

    Joined:
    Feb 23, 2005
    Messages:
    14,209
    Location:
    Midlothian, TX
    Display Name:

    Display name:
    3Green
    Sorry, Ron... I fell into TWO classic traps here:

    1) The resurrected old post (didn't notice the date);
    2) Replying before reading the entire thread.

    You'd think I'd learn... :rolleyes: :D
     
  30. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    If you look in the books, they used to define a "precision" approach as one in which electronic glide path guidance was provided. Thus, the LPV approaches (and to a lesser extent, the LNAV/VNAV and Baro-VNAV) seemed to be precision approaches. Only since the FAA better clarified that within the last two years has the issue been clear by saying that GPS-based glidepath guidance is not considered to be the same "electronic glide path" that PAR, MLS, and ILS provide.
     
  31. TMetzinger

    TMetzinger Final Approach

    Joined:
    Mar 6, 2006
    Messages:
    9,885
    Location:
    Northern Virginia
    Display Name:

    Display name:
    Tim
    Yah - I missed the age of the original thread.
     
  32. MauleSkinner

    MauleSkinner Final Approach

    Joined:
    Oct 25, 2005
    Messages:
    5,171
    Location:
    Wichita, KS
    Display Name:

    Display name:
    MauleSkinner
    Maybe we need to get Joe to change the title of the thread to "LPV is it precision or non-precision? This is an old thread...ignore Ron's question in post #..." :D
     
  33. gprellwitz

    gprellwitz Touchdown! Greaser!

    Joined:
    Jun 19, 2005
    Messages:
    12,952
    Location:
    Romeoville, IL
    Display Name:

    Display name:
    Grant Prellwitz
    Or Ron could go edit the question himself, saying that it's been answered since! But then again, he may LIKE having to continually point out to people that he asked it two years ago! :)
     
  34. Dave Siciliano

    Dave Siciliano Final Approach

    Joined:
    Feb 27, 2005
    Messages:
    6,438
    Location:
    Dallas, Texas
    Display Name:

    Display name:
    Dave Siciliano
    Notice that I responded to the 2007 original post with a 2007 reference <g>

    Best,

    Dave
     
  35. sba55

    sba55 En-Route

    Joined:
    May 12, 2007
    Messages:
    2,558
    Location:
    Marin County, CA
    Display Name:

    Display name:
    sba55
    Ohhh MLS. I'm sad that it never made it! Just like ILS except more expensive!
     
  36. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    GPS put a big stake right through its heart. What surprises me is that there are still a couple of MLS approaches published out there -- the FAA has to pay to maintain the ground facilities and flight check the approaches periodically. Given that there are probably only like two planes in the USA with MLS equipment, that seems wasteful to me.
     
  37. TangoWhiskey

    TangoWhiskey Touchdown! Greaser!

    Joined:
    Feb 23, 2005
    Messages:
    14,209
    Location:
    Midlothian, TX
    Display Name:

    Display name:
    3Green
    Yeah, but you can cook your Hot Pocket while shooting an approach to minimums.
     
  38. KennyFlys

    KennyFlys Guest

    No, not the practical test. I was referring to the FAA flight checks done to test and verify approach equipment accuracy. Is there a difference in the tolerance they seek between "semi-precision" and "precision"?

    John may better know the answer to that question.

    As far as MLS being lost... thank Reagan. Of course, look at the en route navigation opened up to us as a result? Declassification was a good thing.
     
  39. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    Yes, there is, but I don't know the exact details. However, you can get a rough idea by looking in Section 1 of the AIM for the basic tolerances for each type of approach (e.g., ILS GS about 90 feet thick vertically at the MM [1.4 degrees at 4000 feet distance from antenna] vs 35-50 meter maximum vertical error for LPV).
     
  40. Graueradler

    Graueradler Pattern Altitude

    Joined:
    Apr 11, 2005
    Messages:
    2,021
    Location:
    Russellville, AR
    Display Name:

    Display name:
    Graueradler
    So I have to have 800-2 to use it as an alternate but can fly it to posted mins of 225-1 when I get there?