LP approach without other minimums lines on the chart

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pstan

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Stan
Hoping the wisdom of the group can help me here. I'm looking for an LP approach to a runway where there is NOT an LNAV, LNAV/VNAV, nor an LPV approach.

That is, the approach chart does NOT have a line for LNAV, LNAV/VNAV, nor LPV minimums, but does for LP.

And....as an aside....just a thought here....is there any approach with an LP minimums line AND LPV minimums line?

thanks

Stan
 
The RNAV Z approaches for both 12 and 30 at Half Moon Bay, KHAF, are both LPV mins only. The RNAV Y approaches for both runways only have LNAV and circling mins

Edit: whoops misread the post. Thought it was asking for LPV only. My bad
 
pstan said:
Hoping the wisdom of the group can help me here. I'm looking for an LP approach to a runway where there is NOT an LNAV, LNAV/VNAV, nor an LPV approach.

That is, the approach chart does NOT have a line for LNAV, LNAV/VNAV, nor LPV minimums, but does for LP.

And....as an aside....just a thought here....is there any approach with an LP minimums line AND LPV minimums line?

thanks

Stan
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LP won't be used if the vertical obstacle surfaces in the final segment permit LPV (and the necessary vertical surveys are done and the runway is correctly marked). If LPV doesn't qualify, then neither will LNAV/VNAV. And, LP won't be published unless at least a 20' reduction in MDA can be achieved from LNAV minimums.
 
pstan said:
Hoping the wisdom of the group can help me here. I'm looking for an LP approach to a runway where there is NOT an LNAV, LNAV/VNAV, nor an LPV approach.

That is, the approach chart does NOT have a line for LNAV, LNAV/VNAV, nor LPV minimums, but does for LP.

And....as an aside....just a thought here....is there any approach with an LP minimums line AND LPV minimums line?

thanks

Stan
Click to expand...
I can't remember ever seeing that. It wouldnt follow much of a logic to do it. Maybe if there was an airport at the bottom of the Grand Canyon where the LP airspace to be protected was narrow enough to be between the rims but the LNAV space wasn't. The LNAV MDA would be like a Mile AGL. Even then the missed approach would probably prevent establishing an LP MDA that far down beneath the rims
 
That would be an interesting find. I find it difficult to imagine a GPS-based approach that req
aterpster said:
LP won't be used if the vertical obstacle surfaces in the final segment permit LPV (and the necessary vertical surveys are done and the runway is correctly marked). If LPV doesn't qualify, then neither will LNAV/VNAV. And, LP won't be published unless at least a 20' reduction in MDA can be achieved from LNAV minimums.
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Which makes sense - no LP if there are LPV minima. From a required equipment standpoint, they are the pretty much the same - GPS plus WAAS.
 
midlifeflyer said:
That would be an interesting find. I find it difficult to imagine a GPS-based approach that req

Which makes sense - no LP if there are LPV minima. From a required equipment standpoint, they are the pretty much the same - GPS plus WAAS.
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An approach cannot have both LP and LPV minimums because of the WAAS path record in the database. Can't have two path records in one RNAV approach.
 
AKiss20 said:
The RNAV Z approaches for both 12 and 30 at Half Moon Bay, KHAF, are both LPV mins only. The RNAV Y approaches for both runways only have LNAV and circling mins

Edit: whoops misread the post. Thought it was asking for LPV only. My bad
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I'm not sure you are really misreading.
aterpster said:
An approach cannot have both LP and LPV minimums because of the WAAS path record in the database. Can't have two path records in one RNAV approach.
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So I can remove the "pretty much" in my post? :D
 
midlifeflyer said:
Interesting. An FMS approval issue rather than an RNAV issue since an FMS will handle the approaches differently. Makes sense. Thanks.
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I could be misremembering but I believe the 480's earlier software releases did not support LP approaches either. I'm not certain since although I have the most recent software (2.4), I've yet to fly an LP.
 
azure said:
I could be misremembering but I believe the 480's earlier software releases did not support LP approaches either. I'm not certain since although I have the most recent software (2.4), I've yet to fly an LP.
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The limitations of equipment is a different issue than what appears on the charts. Given equipment limitations, I can certainly see an equipment provider choosing not to include LP-specific items on an LPV approach (even if the chart has minimums for both). The reasons to fly an LP when you have LPV capability are pretty limited.

Here's an example of the same thing. If you load an ILS or LOC approach in a Garmin GNS or GTN with a Jepp database, you will not see any LOC step-down fixes inside the FAF. For example, if you load the KTTA ILS or LOC 3, AMIRS is not included. That's a choice Garmin made to limit the size of the Jepp worldwide database used in the units. OTOH, the same units with the Garmin database have separate loads for the ILS and the LOC since the database is smaller.
 
midlifeflyer said:
The limitations of equipment is a different issue than what appears on the charts. Given equipment limitations, I can certainly see an equipment provider choosing not to include LP-specific items on an LPV approach (even if the chart has minimums for both). The reasons to fly an LP when you have LPV capability are pretty limited.
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As I said previously a WAAS IAP cannot have both LP and LPV minimums.

Here's an example of the same thing. If you load an ILS or LOC approach in a Garmin GNS or GTN with a Jepp database, you will not see any LOC step-down fixes inside the FAF. For example, if you load the KTTA ILS or LOC 3, AMIRS is not included. That's a choice Garmin made to limit the size of the Jepp worldwide database used in the units. OTOH, the same units with the Garmin database have separate loads for the ILS and the LOC since the database is smaller.
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Are you saying if I subscribe to Garmin's Americas database I will see AMIRS but I will not if I have Garmin's Worldwide database? My impression was they are limiting the Worldwide database to airports with runways of 4,000 feet in length, or greater. (to try to stay within their 20 megabyte capacity.)
 
midlifeflyer said:
The limitations of equipment is a different issue than what appears on the charts. Given equipment limitations, I can certainly see an equipment provider choosing not to include LP-specific items on an LPV approach (even if the chart has minimums for both). The reasons to fly an LP when you have LPV capability are pretty limited.
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I posted my comment because the thread had wandered into discussion of equipment limitations (specifically an FMS). I'm well aware they are separate issues.

(Though in the case of the 480 it was not an approval issue, but a technical software limitation.)
Here's an example of the same thing. If you load an ILS or LOC approach in a Garmin GNS or GTN with a Jepp database, you will not see any LOC step-down fixes inside the FAF. For example, if you load the KTTA ILS or LOC 3, AMIRS is not included. That's a choice Garmin made to limit the size of the Jepp worldwide database used in the units.
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Yes, that's true with the 480 as well. You need to refer to the chart and use the "DME" from the RWxx waypoint to determine the stepdowns.

But that's not exactly the same thing as what I was talking about, since AFAIK it wasn't a decision to not include the LP approaches in the database. Rather the earlier software did not have support for the newer approach type - possibly the scaling of the course width on the FAS, though I'm not sure of the exact reason.
 
aterpster said:
As I said previously a WAAS IAP cannot have both LP and LPV minimums.
Are you saying if I subscribe to Garmin's Americas database I will see AMIRS but I will not if I have Garmin's Worldwide database? My impression was they are limiting the Worldwide database to airports with runways of 4,000 feet in length, or greater. (to try to stay within their 20 megabyte capacity.)
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Yep. Just a minor correction, the worldwide database in the Garmin units is from Jepp; the North America database is Garmin's.

If you subscribe to Garmin North America and load approaches to KTTA, there will be separate entries for the ILS 3 and the LOC 3 (4 all due to the Y and Z flavors). The LOC has AMIRS, the ILS 3 does not.

If you subscribe to Jepp Worldwide and load approaches to KTTA, there will only be entries for the ILSes and AMIRS will not be listed as a waypoint on the approach. AMIRS is in the database; just not part of the approach.

The full Jepp database includes both the ILS and the LOC (including AMIRS); this is Garmin's choice of what to include. Same reason as you say - database size. Multiply the KTTA approaches by the number of ILS or LOCs with a similar FAC stepdown and multiply that by the approaches doubled up with Y and Z flavors, and you have a pretty big increase in size.

I came across this weirdo as the result of a question from another instructor. He was doing an IPC and wanted to do the LOC only as the nonprecision approach. It was the first time he used the ILS 3 and was surprised to find no AMIRS. Knowing my head is full of aviation trivia, he asked me if I knew what was up. I had no clue, but having lived about 5 minutes from Jepp for 20 years I knew the right folks to ask. Whether it's tru of other GPS units, I don't know.
 
azure said:
since AFAIK it wasn't a decision to not include the LP approaches in the database. Rather the earlier software did not have support for the newer approach type - possibly the scaling of the course width on the FAS, though I'm not sure of the exact reason.
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Can you explain that a bit more? It had the support to laterally scale an LPV with both horizontal and vertical scaling but not an LP with only lateral scaling?
 
midlifeflyer said:
Can you explain that a bit more? It had the support to laterally scale an LPV with both horizontal and vertical scaling but not an LP with only lateral scaling?
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If it didn't know anything about that type of approach, how could it know what scaling to apply or whether to apply LNAV scaling or LPV scaling? ;)

Again, this is just a guess. I really am not sure how these details are stored internally in the database, whether it is explicitly with scaling or with identifiers for each of the legs that are looked up in a table stored in firmware to give the scaling descriptions. I am assuming it is the latter and that a different identifier is used for the FAS for an LP approach than for an LPV, that the earlier software had no knowledge of. It could always be something totally different too. :)
 
midlifeflyer said:
Can you explain that a bit more? It had the support to laterally scale an LPV with both horizontal and vertical scaling but not an LP with only lateral scaling?
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LP certification came later than LPV. Some boxes aren't certified for LP.
midlifeflyer said:
I came across this weirdo as the result of a question from another instructor. He was doing an IPC and wanted to do the LOC only as the nonprecision approach. It was the first time he used the ILS 3 and was surprised to find no AMIRS. Knowing my head is full of aviation trivia, he asked me if I knew what was up. I had no clue, but having lived about 5 minutes from Jepp for 20 years I knew the right folks to ask. Whether it's tru of other GPS units, I don't know.
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It does apply to other units. I think the AC for GPS units specifically states that step down fixes inside the FAF may be omitted, and distance from the MAP can be used to identify these fixes.

Of course, some genius in a brain trust somewhere decided to start coding fixes outside the FAF as step downs, which will also be omitted...including a mandatory altitude fix (PESME) on the RNAV X RW6 at Teterboro.:eek:
 
azure said:
If it didn't know anything about that type of approach, how could it know what scaling to apply or whether to apply LNAV scaling or LPV scaling? ;)
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what LNAV scaling? We're talking about LP vs LPV: Localizer Performance vs Localizer Performance with Vertival guidance.
 
Sounds like you're in an argumentative mood Mark. Not in the mood to engage you right now. I just wanted to comment that even some GA GPSs may not support the new LP approach styles for software reasons. Having done that I'll bow out and let you have the last word...
 
azure said:
If it didn't know anything about that type of approach, how could it know what scaling to apply or whether to apply LNAV scaling or LPV scaling? ;)

Again, this is just a guess. I really am not sure how these details are stored internally in the database, whether it is explicitly with scaling or with identifiers for each of the legs that are looked up in a table stored in firmware to give the scaling descriptions. I am assuming it is the latter and that a different identifier is used for the FAS for an LP approach than for an LPV, that the earlier software had no knowledge of. It could always be something totally different too. :)
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Both LP and LPV have a complex path record, which is on the source document and must be coded by Jeppesen and LIDO into the approach database. Attached is the path record for F70 LPV Rwy 18:
 

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azure said:
Sounds like you're in an argumentative mood Mark. Not in the mood to engage you right now. I just wanted to comment that even some GA GPSs may not support the new LP approach styles for software reasons. Having done that I'll bow out and let you have the last word...
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I'm not arguing. I'm asking. I really don't understand what LNAV scaling has to do with the difference between LP and LPV. I don't claim to be a TERPS expert, GPS certification guru, or database programmer. I assume that two approaches that use localizer performance for lateral navigation use the same lateral scaling. If I'm wrong in that, I'd like to understand.

If you are just saying that the GPS or FMS or whatever was not programmed to recognize the existence of an LP-based approach that didn't have a vertical guidance component, yeah. I have no reason to disagree and accepted that there will be equipment limitations a bunch of posts ago.
 
midlifeflyer said:
I'm not arguing. I'm asking. I really don't understand what LNAV scaling has to do with the difference between LP and LPV. I don't claim to be a TERPS expert, GPS certification guru, or database programmer. I assume that two approaches that use localizer performance for lateral navigation use the same lateral scaling. If I'm wrong in that, I'd like to understand.
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I don't follow this. Having said that LP and LPV are an angular system, exactly like LOC and ILS. The angular ramp down of LP and LPV begins 2 miles prior to the FAF and reaches a width of + or - 300/350 feet about 1,000 feet from the approach end of the runway. The TERPs protected area for LP are the same as for a LOC approach. LPV is the same as ILS.

LNAV is a linear system and goes from terminal width + or -1 mile to + or - 0.30 miles. This ramps down from 1.0 to 0.3 begins 2 miles prior to the FAF. Garmin elected in their WAAS navigators to have LNAV ramp down exactly like LP and LPV. But, the alerting and monitoring remain at 0.30 in the final segment, unlike LP and LPV, where alerting an monitoring follow the decreasing angular width until Suspend appears at the MAP.

FWIW.
 
As the OP, thanks to all, especially PNWGuy for finding the ORS approach, and aterpster for his insights. Stan
 
aterpster said:
I don't follow this. Having said that LP and LPV are an angular system, exactly like LOC and ILS. The angular ramp down of LP and LPV begins 2 miles prior to the FAF and reaches a width of + or - 300/350 feet about 1,000 feet from the approach end of the runway. The TERPs protected area for LP are the same as for a LOC approach. LPV is the same as ILS.

LNAV is a linear system and goes from terminal width + or -1 mile to + or - 0.30 miles. This ramps down from 1.0 to 0.3 begins 2 miles prior to the FAF. Garmin elected in their WAAS navigators to have LNAV ramp down exactly like LP and LPV. But, the alerting and monitoring remain at 0.30 in the final segment, unlike LP and LPV, where alerting an monitoring follow the decreasing angular width until Suspend appears at the MAP.

FWIW.
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I think we are on exactly the same page.
 
Mark,

The original WAAS Garmin systems did not support LP approach types at all. LPV procedures came before LP procedures were ever charted. Many G1000 systems do not support LP to this day. Unless one sees LP as the annunciation, one may not fly an RNAV (GPS) procedure to the LP minimums. The original Garmin systems did not support LP+V similar to LNAV+V and many installed systems are not able to do the +V. The original WAAS Garmin AFMS supported GPS approach to LPV, LNAV/VNAV and LNAV. LNAV+V advisory GP was also supported if it annunciated. Later LP was added. Even later LP+V was added. Not all systems have the software updates for LP and LP+V. A charting standard several years back screwed up the Garmin GPS navigators because of a bright idea to put a glide angle of zero in the database. This was intended to indicate that advisory vertical guidance should not be used with the LP procedure in cases where it was not appropriate. It had the unintended consequence that it caused a flight time software failure in the Garmin systems that did not even support advisory vertical guidance at the time. The only solution for Garmin was to delete all of the affected procedures (some 60+) from the database until a software fix could be implemented.

As far as LP verses LPV, they can't be included on the same procedure for both technical and policy reasons. The main difference is that LPV is a vertically guided procedure and LP is not.
 
John Collins said:
Mark,

The original WAAS Garmin systems did not support LP approach types at all. LPV procedures came before LP procedures were ever charted. Many G1000 systems do not support LP to this day. Unless one sees LP as the annunciation, one may not fly an RNAV (GPS) procedure to the LP minimums. The original Garmin systems did not support LP+V similar to LNAV+V and many installed systems are not able to do the +V. The original WAAS Garmin AFMS supported GPS approach to LPV, LNAV/VNAV and LNAV. LNAV+V advisory GP was also supported if it annunciated. Later LP was added. Even later LP+V was added. Not all systems have the software updates for LP and LP+V. A charting standard several years back screwed up the Garmin GPS navigators because of a bright idea to put a glide angle of zero in the database. This was intended to indicate that advisory vertical guidance should not be used with the LP procedure in cases where it was not appropriate. It had the unintended consequence that it caused a flight time software failure in the Garmin systems that did not even support advisory vertical guidance at the time. The only solution for Garmin was to delete all of the affected procedures (some 60+) from the database until a software fix could be implemented.

As far as LP verses LPV, they can't be included on the same procedure for both technical and policy reasons. The main difference is that LPV is a vertically guided procedure and LP is not.
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Thanks. I understood all of that from the beginning except the bold partS.
 
Airborne equipment limitations aside, has anyone found any other approaches that have only LP and Circling minimums besides that one at ORS?
 
midlifeflyer said:
I'm not arguing. I'm asking. I really don't understand what LNAV scaling has to do with the difference between LP and LPV. I don't claim to be a TERPS expert, GPS certification guru, or database programmer. I assume that two approaches that use localizer performance for lateral navigation use the same lateral scaling. If I'm wrong in that, I'd like to understand.
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I never said that. LNAV and LP are similar in that both have only lateral guidance, but the scaling and lateral profile are completely different. LPV and LP have the same lateral scaling AFAIK, but LPV has vertical guidance and LP does not. What I'm not sure of is how the unit calculates the scaling from the info in the database, and was suggesting that MAYBE due to the internal representation of that information in the database, the unit doesn't know how to properly calculate that scaling for LP without a software upgrade. (Though from the path record that @aterpster posted, that seems unlikely to me now.)
If you are just saying that the GPS or FMS or whatever was not programmed to recognize the existence of an LP-based approach that didn't have a vertical guidance component, yeah. I have no reason to disagree and accepted that there will be equipment limitations a bunch of posts ago.
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And that is basically all I was saying; everything else was a WAG on my part.
 
John Collins said:
Mark,

The original WAAS Garmin systems did not support LP approach types at all. LPV procedures came before LP procedures were ever charted. Many G1000 systems do not support LP to this day. Unless one sees LP as the annunciation, one may not fly an RNAV (GPS) procedure to the LP minimums. The original Garmin systems did not support LP+V similar to LNAV+V and many installed systems are not able to do the +V. The original WAAS Garmin AFMS supported GPS approach to LPV, LNAV/VNAV and LNAV. LNAV+V advisory GP was also supported if it annunciated. Later LP was added. Even later LP+V was added. Not all systems have the software updates for LP and LP+V. A charting standard several years back screwed up the Garmin GPS navigators because of a bright idea to put a glide angle of zero in the database. This was intended to indicate that advisory vertical guidance should not be used with the LP procedure in cases where it was not appropriate. It had the unintended consequence that it caused a flight time software failure in the Garmin systems that did not even support advisory vertical guidance at the time. The only solution for Garmin was to delete all of the affected procedures (some 60+) from the database until a software fix could be implemented.

As far as LP verses LPV, they can't be included on the same procedure for both technical and policy reasons. The main difference is that LPV is a vertically guided procedure and LP is not.
Click to expand...
Thanks for the details John. It appears, then, that the reason the pre-2.4 480 did not support LP is simply that it didn't know about the approach type and therefore couldn't annunciate "LP"?

Also: are the Jepp databases for the 480 supposed to contain the "+V" for LP and LNAV procedures where it is appropriate? The reason I ask is because there used to be advisory vertical guidance on the RNAV 35 @ KMPV a couple of years ago, but it disappeared and I have not seen it since either here or anywhere else. I'm not sure if it was simply decided that the +V should be deleted from those approaches (and there might well be obstacle clearance issues at KPMV that preclude it) but retained in others, if Jepp simply elected to not support that feature any more in the database for the 480, or whether the 2.4 software upgrade eliminated support for it.
 
Azure,

GNS480 software Version 2.3 added LP. Version 2.4 added support for LP+V. The RNAV (GPS) 35 at KMPV is LNAV only and it does not have a published VDA/TCH, it also has the old profile note "Descent Angle NA" which was an indication that there were obstacles along the path in the visual segment as determined by Flight test along the path from the "unpublished VDP" to the runway threshold, so regardless if there were LP minimums or just LNAV minimums, +V was not authorized. The note has been superseded for newly published procedures to read as "Visual Segment - Obstacles". Current standards for a straight in LNAV or LP publish a VDA and TCH when +V is permitted. Prior to the time the procedure was last amended, it would likely have been LNAV+V, but subsequent flight tests indicated that the obstacles in the visual segment were hazardous, the +V was dropped. LP would have been published if it allowed at least a 20 foot reduction in the MDA.
 
The GNS480 never had the bug that would have blocked some LP procedures from being in the database. If the approach was approved for LP, it should have been supported from Version 2.3 onward.
Some airports up in the NE that should have LP+V would be: KRUT 1; KEFK 36; KFSO 19; 1B0. One that would have LP but no +V would be KHUL 5.
 
John Collins said:
The GNS480 never had the bug that would have blocked some LP procedures from being in the database. If the approach was approved for LP, it should have been supported from Version 2.3 onward.
Some airports up in the NE that should have LP+V would be: KRUT 1; KEFK 36; KFSO 19; 1B0. One that would have LP but no +V would be KHUL 5.
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I know it was an issue of lack of support for the approach type, not firmware bug. It might have been version 2.2 I guess, though I thought the announcement said we would have to upgrade to 2.4 to get LP approaches. It's been a couple of years now, my memory might be faulty.

I will check out one of those approaches next time I'm out to see if I get the +V.
 
John Collins said:
Azure,

GNS480 software Version 2.3 added LP. Version 2.4 added support for LP+V. The RNAV (GPS) 35 at KMPV is LNAV only and it does not have a published VDA/TCH, it also has the old profile note "Descent Angle NA" which was an indication that there were obstacles along the path in the visual segment as determined by Flight test along the path from the "unpublished VDP" to the runway threshold, so regardless if there were LP minimums or just LNAV minimums, +V was not authorized. The note has been superseded for newly published procedures to read as "Visual Segment - Obstacles". Current standards for a straight in LNAV or LP publish a VDA and TCH when +V is permitted. Prior to the time the procedure was last amended, it would likely have been LNAV+V, but subsequent flight tests indicated that the obstacles in the visual segment were hazardous, the +V was dropped. LP would have been published if it allowed at least a 20 foot reduction in the MDA.
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That's pretty much what I expected. The obstacle is likely a ridgeline about a half mile south of the threshold. There is a classic video somewhere on the AOPA site of two pilots who came very close to some trees on that ridge flying that approach at night. I'm not sure if that was before the "NA for night landing on rwy 5, 35" note was added, but if you try to descend from MDA before crossing that ridge, you could get uncomfortably close to those treetops. I flew that approach a few times before that note was added (including before the +V was removed) and was always nervously aware of that ridge.
 
John Collins said:
Mine too, that's why I looked up the SB's for 2.3 and 2.4 software upgrades. I keep all that junk.
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I don't have the SB for 2.3 because I'm pretty sure that was the revision installed when I bought the airplane. But I kept the 2.4 SB and just looked it up. You're definitely right, it was support for LP+V, as well as a correction for a scaling bug that affected certain LNAV/VNAV and LNAV+V approaches. As a matter of fact I probably just misread the 2.4 SB back then in haste. Mea culpa. :redface:
 
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