LPV is it precison or non-precision

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.
 
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Areeda said:
OK I'm doing a LPV approach RNAV http://poa.areeda.com/dttp/index.php?act=viewDoc&inline&db=ttp&docn=1896
You may have to register. Start with username dttp, password: poatester

You are doing an IPC does this one count as a precsion or no-precision approach.

Joe
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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.
 
Ron Levy said:
Can you point to a source document for that?
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This is my problem. The only approaches defined as precision were the ILS and PAR and GLS. APV is in a different class.

14CFR Part 1 said:
Nonprecision approach procedure means a standard instrument approach procedure in which no electronic glide slope is provided.

Precision approach procedure means a standard instrument approach procedure in which an electronic glide slope is provided, such as ILS and PAR.
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AIM 5-4-5(a)(7) said:
(a) Precision Approach (PA). An instrument approach based on a navigation system that provides course and glidepath deviation information meeting the precision standards of ICAO Annex 10. For example, PAR, ILS, and GLS are precision approaches.

(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.

(c) Nonprecision Approach (NPA). An instrument approach based on a navigation system which provides course deviation information, but no glidepath deviation information. For example, VOR, NDB and LNAV. As noted in subparagraph h, Vertical Descent Angle (VDA) on Nonprecision Approaches, some approach procedures may provide a Vertical Descent Angle as an aid in flying a stabilized approach, without requiring its use in order to fly the procedure. This does not make the approach an APV procedure, since it must still be flown to an MDA and has not been evaluated with a glidepath.
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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
 
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Ron Levy said:
Can you point to a source document for that?
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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.
 
ghogue said:
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.
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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.
 
ghogue said:
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.
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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.
 
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Areeda said:
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
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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.
 
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.
 
lancefisher said:
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.
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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
Inverse%20A%20Icon.gif
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
Inverse%20A%20Icon.gif
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
Inverse%20A%20Icon.gif
NA from RNAV (GPS) and GPS procedures will take some time.


gary
 
ghogue said:
Lance,
Is this what you were referring to? The info is in AIM (see below).
gary
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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.
 
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.
 
lancefisher said:
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.
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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
​
 
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.
 
Ron Levy said:
Can you point to a source document for that?
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In the Introduction to the proposed new instrument PTS it is made clear that there are no satellite-based precision approaches.

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

Bob Gardner
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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.
 
Ron Levy said:
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.
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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:

For flight planning purposes, weather information
must be reviewed in order to determine the necessity
and suitability of alternate airports. For Part 91 operations,
the 600-2 and 800-2 rule applies to airports with
precision and nonprecision approaches, respectively.
Approaches with vertical guidance (APV) are considered
semi-precision and nonprecision since they do not
meet the International Civil Aviation Organization
(ICAO) Annex 10 standards for a precision approach.
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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
 
"semi-precision"?

How do those measure up in a flight check with a "precision" approach?
 
KennyFlys said:
"semi-precision"?

How do those measure up in a flight check with a "precision" approach?
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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.
 
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".
 
Ron Levy said:
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.
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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
 
TMetzinger said:
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".
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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.
 
Ron Levy said:
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.
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Yah - I missed the age of the original thread.
 
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
 
MauleSkinner said:
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
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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! :)
 
Notice that I responded to the 2007 original post with a 2007 reference <g>

Best,

Dave
 
Ron Levy said:
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.
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Ohhh MLS. I'm sad that it never made it! Just like ILS except more expensive!
 
sba55 said:
Ohhh MLS. I'm sad that it never made it! Just like ILS except more expensive!
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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.
 
Ron Levy said:
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.
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Yeah, but you can cook your Hot Pocket while shooting an approach to minimums.
 
Ron Levy said:
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.
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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.
 
KennyFlys said:
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"?
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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).
 
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?
 
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