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Old January 7th 07, 05:33 AM posted to rec.aviation.ifr
Andrew Sarangan
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Posts: 382
Default LPV vs LNAV/VNAV?


Peter R. wrote:
Andrew Sarangan wrote:

Something I never understood is why LNAV approaches don't automatically
show a glideslope so that the airplane arrives at the MDA at the VDP.


Perhaps because it wasn't part of the certification at the time?


Perhaps my comment was not clearly stated. When you fly an LNAV
approach (or any nonprecision approach for that matter) instead of the
traditional dive and drive you can mentally calculate the vertical
speed required (VSR) to arrive at the VDP at a constant glide angle .
That mental calculation could be easily performed by the GPS and
displayed as a glideslope. But I have not seen any GPS do that.
Certification is irrelevant. We are not talking about a lower minimum
or anything new that we not already allowed to do.