WAAS for GNS 430/530?

Victor J. Osborne, Jr. wrote:

But does this feature work as enhancements to existing SDF/LOC approaches?

My reading of the advertising-speak is that it can build a descent profile
for any approach. I've some question about that (ie. what if the straight
line from FAF to VDP passes under a stepdown), but I don't know that I've
interpreted the advertising-speak accurately.

- Andrew

"Roy Smith" wrote in message
...
In article ,
Matt Barrow wrote:

"Andrew Gideon" wrote in message
gonline.com...
Matt Barrow wrote:

Think about breaking out at the MAP...you've got 0.2 seconds to make
your
decision.

Perhaps I'm misinterpreting what you've written, but how is this
different
than a 'real' precision approach?


When you reach the MAP after D&D, you're stable in three axes. How would
you
rather be when looking for the runway?

When you reach the MAP after following a glide slope, you should also
be stable in three axes (heading, pitch, and bank should all be
constant). Even better, if you see the runway, you can continue to
hold that attitude down to the surface.

If anything, the slight nose-down pitch attitude should make it easier
to see the runway, compared to having to search for it over the nose
in level flight after a dive-and-drive.

And at the MAP, your rate of descent must be reduced to zero, so the
stability in three axes doesn't hold.

"Scott Moore" wrote in message
...
Andrew Gideon wrote:
Matt Barrow wrote:


Think about breaking out at the MAP...you've got 0.2 seconds to make
your
decision.


Perhaps I'm misinterpreting what you've written, but how is this
different
than a 'real' precision approach?

- Andrew


I believe he is saying that dive and drive gets you broken out sooner,
since
you are down at the minimum altitude considerably befor the map.

You've got it.

Did you read Deakins article? He's a much better writer/spokesman than I.

"Andrew Gideon" wrote in message
gonline.com...
Scott Moore wrote:

Think about breaking out at the MAP...you've got 0.2 seconds to make
your
decision.


Perhaps I'm misinterpreting what you've written, but how is this
different than a 'real' precision approach?

I believe he is saying that dive and drive gets you broken out sooner,
since you are down at the minimum altitude considerably befor the map.

Perhaps, but that's still the same as a precision approach.

No, it's not. A PA breaks you out AT the MAP, D&D breaks your out eealier,
perhaps _much_ earlier.

If reaching the
MDA at the same moment that one much decide whether or not to continue the
approach (ie the VDP) is a Bad Thing, why isn't it bad on a precision
approach?

It's the dreaded "approach to minimums". In the turbine equipment, it's
piloted by (usually) more experienced pilots. In such equipment it HAS to be
done as a stabilized approach. Why would a prop/piston driver put that onus
on themselves?

"Scott Moore" wrote in message
...



If anything, the slight nose-down pitch attitude should make it easier
to see the runway, compared to having to search for it over the nose
in level flight after a dive-and-drive.



A factor I didn't see mentioned:

A coupled autopilot can fly a WAAS approach. It cannot do dive and drive.


A coupled approach does let you keep your eyes outside, especially during
the transition phase, but how many are equipped with AP's that can do
coupled approaches?

Remember: CONTEXT.

Matt Barrow wrote:


A coupled approach does let you keep your eyes outside, especially during
the transition phase, but how many are equipped with AP's that can do
coupled approaches?

Remember: CONTEXT.




I've got an WAAS-enabled GPS, GPSS, and an autopilot that will fly
coupled approaches.

"Ron Natalie" wrote in message
m...
Matt Barrow wrote:


A coupled approach does let you keep your eyes outside, especially
during
the transition phase, but how many are equipped with AP's that can do
coupled approaches?

Remember: CONTEXT.




I've got an WAAS-enabled GPS, GPSS, and an autopilot that will fly
coupled approaches.

So do I. We're a distinct minority. So what?

Remember: CONTEXT.

"Andrew Gideon" wrote in message =
online.com...
Victor J. Osborne, Jr. wrote:
=20
But does this feature work as enhancements to existing SDF/LOC =
approaches?
=20
My reading of the advertising-speak is that it can build a descent =
profile
for any approach. I've some question about that (ie. what if the =
straight
line from FAF to VDP passes under a stepdown), but I don't know that =
I've
interpreted the advertising-speak accurately.
=20
- Andrew

I agree the "advertising-speak" seems to say what you interpreted.
But I've yet to encounter a computed glide slope for any SDF/LOC
or VOR approaches in my CNX80.
(If some are there, though, someone will surely tell us so.)

However, it seems like all RNAV (GPS) approaches, as well as a majority
of the plain-vanilla GPS approaches do give me vertical guidance,
to which I can couple my 3-axis autopilot if I so choose.
During practice, I make sure I'm comfortable either coupled or =
uncoupled.

Regarding the "straight line from FAF to VDP passing under a stepdown",
that's handled by a charting a delay before descending until reaching a =
point
from which the stabilized descent *will* meet obstruction-clearance =
criteria.
The CNX80/GNS480 follows that charting.
It does not start the descent from the FAF when it's incorrect to do so.

Matt Barrow wrote:
"Ron Natalie" wrote in message
m...

Matt Barrow wrote:


A coupled approach does let you keep your eyes outside, especially

during

the transition phase, but how many are equipped with AP's that can do
coupled approaches?

Remember: CONTEXT.




I've got an WAAS-enabled GPS, GPSS, and an autopilot that will fly
coupled approaches.


So do I. We're a distinct minority. So what?

Remember: CONTEXT.


Anybody with a IFR capable GPS is a minority. Anybody with
a really capable IFR panel that's legal to use IFR is a minority.

What freaking CONTEXT are you talking about.

John R. Copeland wrote:

Regarding the "straight line from FAF to VDP passing under a stepdown",
that's handled by a charting a delay before descending until reaching a
point from which the stabilized descent will meet obstruction-clearance
criteria. The CNX80/GNS480 follows that charting.
It does not start the descent from the FAF when it's incorrect to do so.

That's a nice solution; I wish I could see it for myself grin.

- Andrew