Brenor Brophy wrote:
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.


Thanks for the great references, Brenor... and thanks to everyone who replied,
though I won't attempt to apply individually to each.

Dave