I bought the ‘C’ package primarily for the vertical nav capabilities of the autopilot. The ability to couple an ILS is to me a much more significant safety addition than the second NAV radio and OBS head (though having redundancy there is also a good thing.) I find I use Vs hold quite a bit, particularly for descent planning (“lessee, I need 400 fpm down.” click click.)
Worth the extra cash? Hard to measure. Makes for a very pretty avionics stack tho.
With the “B” package there is only the HSI as I understand.
No, that’s not correct. The GNC420 has its own dedicated OBS indicator (bottom left of the panel). So if the HSI goes out, you still have the #2 GPS fully functional. But in any case, the 430 and 420 both have a track indicator on the default nav page, so you could have both nav heads fail and still be able to quite happily fly en-route or a GPS approach - just a little more work (and probably less smoothly if the HI part of the HSI was out too).
With the “B” package there is only the HSI as I understand.
No, that’s not correct. The GNC420 has its own dedicated OBS indicator (bottom left of the panel). So if the HSI goes out, you still have the #2 GPS fully functional. But in any case, the 430 and 420 both have a track indicator on the default nav page, so you could have both nav heads fail and still be able to quite happily fly en-route or a GPS approach - just a little more work (and probably less smoothly if the HI part of the HSI was out too).
Clyde:
Thanks for correcting that. My understanding now is that each unit, whether a 430 or a 420, has a nav head. The 420 would not have the glideslope I guess. But they both ALSO have the map features in the unit that ALSO allows course guidance. So the unit , in essence, backs up itself to some degree if the nav head fails. THAT IS QUITE NICE.
How many of you out there cureenly fly with 2 vor/glideslope nav heads.
Brain
With the “B” package there is only the HSI as I understand.
No, that’s not correct. The GNC420 has its own dedicated OBS indicator (bottom left of the panel). So if the HSI goes out, you still have the #2 GPS fully functional. But in any case, the 430 and 420 both have a track indicator on the default nav page, so you could have both nav heads fail and still be able to quite happily fly en-route or a GPS approach - just a little more work (and probably less smoothly if the HI part of the HSI was out too).
Clyde:
Thanks for correcting that. My understanding now is that each unit, whether a 430 or a 420, has a nav head. The 420 would not have the glideslope I guess. But they both ALSO have the map features in the unit that ALSO allows course guidance. So the unit , in essence, backs up itself to some degree if the nav head fails. THAT IS QUITE NICE.
How many of you out there cureenly fly with 2 vor/glideslope nav heads.
Brian
All of you with the “B” package: Do you see any advantages to the other upgrades in the “C” package such as the better auotopilot, electric HSI and extra alternator?
the 2nd alternator is, I think, a must for serious IFR - but you can add it to the B package (we did). The fancy autopilot is not worth the difference in price (to me anyway). And the electric HSI is probably more reliable, but you do at least have a backup vacuum pump, which appears to work well. I hope that Cirrus will make the SR20 an all-electric system in the future. Surely that could not cost much more than the present system with 1 alt and 2 vacuum pumps.
You raise some good points. The cost benefit analysis of the difference between the"B" & “C” package may not be worth the price especially if you add the second alternator. Is there a way ti isolate one alternator from the other in the electrical system?
I would like to hear from folks with the “C” package their analysis of why they went the extra mile.
brian