CNX-80 vs Garmin 430/530

On Sun, 23 Nov 2003 19:38:41 -0800, Jeff wrote:


I am just as happy with using my altimiter, vnav lets you decend about an extra 20 ft or so
( the approach I did today was a 20 ft difference) its not something that is necessary for
me, and its not going to open 100 more airports for me, vnav simply gives you a lower MDA
and its nothing like ignoring a glideslope.
A ILS is a precision approach and a gps approach is not.
Also Vnav is not in wide use as of yet, it will be sometime before its widely available.
You have gone this long without using vnav, why is it a must for you now?
not flamming or anything negative, just a curious question.

At GAI the GPS 14 LNAV has an MDA of 700 AGL, the LNAV/VNAV has a DA
of 400 AGL, and THE LPV (when equipment becomes available) will have a
DA of 300 AGL. That is as good as some ILS approaches. Since the
approach plates do use the term DA for the approaches, that sure makes
me think they are in fact precision approaches.

I went downstairs and got my approach plates, your right its shown as DA, also I was thinking
that a requirement for a precision approach is verticle navagation, so maybe vnav will (or is) a
precision approach, I havnt read enough about it.
Where I live, if we have low clouds, they are full of ice, the sky is clear most of the year,
average 6 inches of rain a year. When I fly to california, where it does get foggy, low clouds
and such, every other airport seems to have an ILS, so vnav is not a big issue for me.

Where I flew today, cedar city, Ut the DA for the ILS is 5800 and a 1/2 mile, the GPS approach
using vnav is 6000 and 1 mile, the airport elevation is 5622 so the ILS gets you down to 200 agl
and the vnav gets you down to 400 AGL. My preference to flying any approach in IMC, where I may
have to decend to minimuns is to use an ILS. My reasoning is because around here, alot of the
VOR and GPS approaches turn you around mountains, not something I really want to do when I cant
see the mountains. So my reasoning for not having a need for vnav is based on several things,
mainly I dont think I would use it because we dont have the weather and the main places I fly
that does have weather I have a choice of airports with ILS's. But I am curious if this vnav is
actualy going to be a precision approach.

Jeff
http://www.turboarrow3.com


ArtP wrote:



At GAI the GPS 14 LNAV has an MDA of 700 AGL, the LNAV/VNAV has a DA
of 400 AGL, and THE LPV (when equipment becomes available) will have a
DA of 300 AGL. That is as good as some ILS approaches. Since the
approach plates do use the term DA for the approaches, that sure makes
me think they are in fact precision approaches.

In article , Jeff
writes:

I heard the update was like $1000, but it may be 1500$, its one of those.
Personally I dont think I will use the vnav, thats why I got the 430, with
exception of vnav and entering in flight plans via the airways they are
esentially the same box.

I have a 430 and like it but they are NOT the same box. The 80 engine is about
5 times faster that the 430. I'm sure that the 1.5K update (late next year)
will make then nearly the same box.

Chuck