"Gerry Caron" wrote in message
...

"Charles Talleyrand" wrote in message
oups.com...

What you get with a real FMS is a whole host of functions that the G1000
can't even contemplate -- sophisticated vertical nav options, take-off
and
landing performance calculations, etc. Those features won't be
obsoleted by
a new nav sensor.

I agree with Karl, no comparison.


I'm not arguing. I just don't understand.

The takeoff and landing calculations seem nice, but not worth zillions
of dollars.
What sophisticated vertical nav functions does a real FM Shave that a
Garmin does not? What's the "needed feature" that's worth an extra
zillion dollars?

P.S. Anyone know the price difference between a Garmin and a Collins
Pro Line?


The T/O and landing calcs may seem like a nicety to a piston driver, but
it's an everyday need in most jets unless every place you fly has 9,000 ft
or more of runway. Add in the fact that fuel and passengers/cargo can be
30 - 50% of your MTOW. Add in temperature and altitude and there can be
significant effort involved in calculating what is essential data. You
really do need to know you can handle an engine failure just before V1 and
still stop on the runway (or continue the takeoff if it fails just after
V1.) Sure, it ain't free, but it's not in the realm of zillions of
dollars.

The vnav and other functions add incremental capabilities. What's the
needed feature? That depends on the plane and who's flying it and the
type of flying they do. Do you need RVSM? CAT II autoland? Part 25
certification?

Quite true for that context.


The price question is hard to answer. First, it's buried in the cost of
the plane and I doubt Cessna (or Hawker/Beechcraft, or Bombardier, etc.)
is willing to explain what their costs are. The second is that Collins
Pro Line is a wide ranging line of avionics that can be tailored to the
needs of anything from a Cessna CJ1 up to a Bombardier CRJ700. Although
many of the pieces are the same, what's in a CJ isn't the same as what's
in a CRJ. At the low end, it appears the functionality and cost of the
Pro Line in the CJ1 was more than Cessna felt they needed or could afford
to include in the Mustang. In general, as aircraft get bigger the
avionics get more complex; so a good rule of thumb is that the overall
avionics cost is typically about 10% of the manufacturer's cost of the
entire plane. (Engines can be 40 - 50%.)

From what that article I linked to (WAAS Benefits Register) in an earlier
post, most of the FMSs out there are not even close to the state-of-the-art
today. Much of the calculation functions will be easily handled by a WAAS
based FMS such as the G1000 (any day now, according to Garmin).

In the end, I think the G1000 will continue to get more features making it
more like the big FMSes. The Collins system will also continue to evolve.

Indeed! Each as the requirements dictate.