LPV minimums higher than LNAV/VNAV?

Landis

Landis

Well-Known Member
During a FIRC class yesterday we were discussing GPS WAAS and the instructor mentioned that there were some approaches that had higher LPV minimums than LNAV/VNAV minimums. Does anyone know of any examples I could look at?

I'm familiar with approaches with higher LNAV/VNAV minimums than LNAV minimums, but haven't yet noticed any with higher LPV than LNAV/VNAV on the same approach.

Thanks in advance.
 
I've seen higher LPV than LNAV (only) because of where the MAP is. I think it was due to the min gradient clear of obstacles from the MAP (closer in on the LPV).
 
I can understand LPV mins higher than LNAV but still can't quite grasp the why or where of higher LPV mins than LNAV/VNAV. Does anyone know of a way to search approaches based on the type of approach rather than the airport?
 
Landis said:
I can understand LPV mins higher than LNAV but still can't quite grasp the why or where of higher LPV mins than LNAV/VNAV. Does anyone know of a way to search approaches based on the type of approach rather than the airport?
Click to expand...
Try this with Google.
site:airnav.com xxxxx
xxxxx being whatever you want to search for.
e.g.
RNAV (GPS)
ILS rwy
VOR rwy 32
ATIS
Smith
Runway 15

The results will show each airnav.com airport entry containing the data you entered.
 
I found one!!! Sceeming thru the apprch plates from FL I found this apprch:
http://204.108.4.16/d-tpp/1008/05232R35.PDF

It is wierd that I didnt thought of this apprch alittle bit sooner since I`ve flown it a couple of times:)


And just for the fun of it Im adding the FAA`s definition on both!

LNAV/VNAV (Lateral Navigation / Vertical Navigation) approaches use lateral guidance (556m
lateral limit) from GPS and/or WAAS and vertical guidance provided by either the barometric
altimeter or WAAS. Aircraft that don’t use WAAS for the vertical guidance portion must have
VNAV-capable altimeters, which are typically part of a flight management system (FMS). FMS
avionics are more expensive than WAAS receivers. When the pilot flies an LNAV/VNAV
approach lateral and vertical guidance is provided to fly a controlled descent, a safer maneuver,
to the runway. The decision altitudes on these approaches are usually 350 feet above the
runway.
Click to expand...


LPV (Localizer Performance with Vertical guidance) is similar to LNAV/VNAV except it is
much more precise (40m lateral limit), enables descent to 200-250 feet above the runway, and
can only be flown with a WAAS receiver. LPV approaches are operationally equivalent to the
legacy instrument landing systems (ILS) but are more economical because no navigation
infrastructure has to be installed at the runway.
Click to expand...

Youre welcome :beer:
 
Landis said:
And there it is. Very nice and much appreciated.

I'm still not convinced as to WHY that happened, but I appreciate seeing the example of one in action. If anyone knows for sure (preferably with citations) how this can happen, I'd appreciate it. But for now I can rest much easier.

Thanks!
Click to expand...

That's weird too, flight visibility requirements for LPV and LNAV/VNAV on those approaches are also higher (1 3/4 versus LNAV and circling minimums of 580/1 (Cat A, B)). A more dangerous maneuver requires less flight visibility (!)...:dunno:

But wait, there's more. Quoth Airnav:

RY 35 RY 35 APCH RATIO 50:1 AT DSPLCD THLD DUE TO PLINE 1020 FT FM THE END OF RY OB.
Click to expand...

That probably has something to do with these requirements. Someone who really groks TERPS (especially the subtle differences between LNAV/VNAV and LPV glidepaths) should fill us in, though.
 
Hattiesburg, MS (HBG) has an RNAV Y (LPV; I think) and Z (LNAV only; again, I think) to runway 13. Higher minimums on the LPV edition.
 
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