FWIW, the GNS480 displays an electronic HSI on its NAV page. I also plan to upgrade my panel with the GNS480, but after spending $11K on the GPS I can't justify spending more on a HSI that doesn't add that much extra. The NSD360 was the cheapest HSI I could find but after some research it seemed like a problem instrument. This quote is from the Avionics West article at http://avionicswest.com/articles/kno..._autopilot.htm

"The most popular Cessna HSI today is the Edo-Aire NSD-360 series. Cessna installed these units in thousands of single and multi-engine aircraft. This compass system is slaved in most cases, but be advised there are many non-slaved NSD-360's in the field. Even with a slaved NSD-360, you must set the compass card once the aircraft is running. After that if everything is working as it should, you shouldn't have to set the compass card again. This HSI, slaved or not, MUST have BOTH vacuum and electrical inputs in order to operate. In other words, if you lose vacuum or the electrical system, this HSI compass card will quit! Expect to pay between $300-500/year to keep your NSD repaired. Sure, you may not need a repair for several years but when your unit does, it really hits the ole pocket book "

This next quote is from an AVWEB article at http://www.avweb.com/news/reviews/182525-1.html

"Not long thereafter, my vacuum-driven NSD-360 HSI started acting up. On several occasions, the slaved heading gyro suddenly wound up 20 or 30 degrees in error, causing the autopilot to take me on an unplanned off-route excursion each time. Although I subsequently diagnosed the problem as being a clogged central vacuum filter, it reminded me that the NSD-360 was a pretty vulnerable instrument, and one that had required (and would continue to require) overhauls every few years at a cost of around $2,800 a pop. Somehow, that made the $8,000 price of the Sandel seem a lot more reasonable. "

So that finished me on the NDS360 and all the other HSI's were way too expensive. I'm going to keep my DG and get a new MD200 CDI to go with the GNS480.

-Brenor

"Dave Butler" wrote in message ...
Please excuse the hijacking of this religious/political forum to raise a
question about flying.

My partners and I are faced with a decision. What would you do?

We plan to update our outdated panel with a GNS480. The CDIs currently installed
are not compatible with the GNS480, so one of them will be replaced.

We could replace the existing CDI with a compatible one for $2000.

We could install a non-slaved NSD360 HSI instead for $3500.

If we install the HSI, the no-longer-used CDI hole can be used for the electric
AI that's been waaaay over on the other side of the panel.

I think I know what we will do (go for the HSI), but I'm collecting opinions.

Is the NSD360 likely to become a maintenance headache?

In the electronic age, does it make sense to install an electromechanical aid to
situational awareness?

Thanks,

Dave