LPV DA NA - Can I fly this approach and to what minimums?

[MauleSkinner]

I don't know of a case where it makes sense to turn off WAAS other than as part of a training exercise.

The only case I could think of is the one you mentioned earlier, which does exist in some airplanes/FMSs.

There are some LNAV/VNAV that are charted with the note "WAAS VNAV not authorized", example TJSJ RNAV (GPS) Rwy 10 in Puerto Rico. I would assume, but don't know for sure that some high end FMS systems that support LPV and Baro/VNAV for the vertical on an LNAV/VNAV could downgrade from LPV using WAAS vertical to LNAV/VNAV using Baro/VNAV for the vertical.

some kind of WAAS outage would require disabling WAAS to use Baro VNAV in these aircraft as well.

 

[Palmpilot]

I don't know of a case where it makes sense to turn off WAAS other than as part of a training exercise. If the GPS is TSO C146, then with an annunciation of LPV, you can fly the procedure to the LPV, LNAV/VNAV or LNAV straight In or circling minimums. If the Annunciation is L/VNAV, then you can fly the procedure to the LNAV/VNAV or LNAV straight in or circling minimums. If the annunciation is LP or LP+V, you can fly to the LP or LNAV straight in or circling minimums. If the annunciation is LNAV or LNAV+V, you can fly to the LNAV straight in or circling minimums. Of course this presumes there are no limitations specified on the approach chart or in a NOTAM and that the charted procedure includes multiple options. The minimums are specified on the chart in a hierarchical order, top to bottom.

Helpful information, but I still haven't managed to memorize what some of those abbreviations stand for!