Dave Butler wrote:
Kelly wrote:

Also, I know how the 396 and 496 differ, but would like to know if
you think the 496 is worth the extra $600. I should also mention
that I like the "6-pack" panel page on the Garmins as a potential
backup in the event of vacuum pump or electrical failure, and wonder
how much difference the faster refresh rate on the 496 makes for
this page.

I think the 396 and 496 both update their navigation solution at 1 Hz.

The difference in refresh rate refers only to the graphic screen
update when you (for example) slew the moving map. I stand ready to be
corrected on this point, however.

I have the 396 and it's fine for depicting nexrad. The graphic screen
update is indeed a bit slow if you're navigating with it and
frequently change scales or slew the map around with the cursor.

I think for the uses you describe, the 396 will do fine in a 172. I
wouldn't depend on either of them as a backup for vacuum in a fast,
slippery airplane.

From Garmin's website.

".Faster 5 Hz GPS updating of map data and "panel page" gives a smoother,
nearly real-time presentation of turn coordinator and HSI."

I'm planning on putting a 496 in my 601XL that's only other flight
instrument is going to be a Dynon EFIS. Because of this the GPS derived
panel in the 496 is of great interest to me as an emergency pack up.

To test I went up in a 496 equipped 172, a hood and another pilot and
simulated a panel is dead and in the soup. I used the 496 Panel page and was
able to get to 500 feet and the right end of the runway with the shiny side
up. I'm sold on the thing. It is critical though to give the instrument time
to average out. Especially airspeed. Don't chase it.