WAAS for GNS 430/530?

Roy Smith wrote:
In article ,
Matt Barrow wrote:

"Andrew Gideon" wrote in message
agonline.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.



A factor I didn't see mentioned:

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

"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.

"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.

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.

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. 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?

- Andrew

"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
...
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.

Doug wrote:

A pilot can use either technique. Depending on the pilot, the aircraft,
and the approach, there are positives and negatives to using dive and
drive vs. stabilized constant descent technique.

The accidents stats don't support any positives for dive-and-drive.



One thing you frequently hear is that you could IMMEDIATELY descend
(helicopter) to the next altitude once you pass the waypoint. NOT true.
There is a maximum decent allowed. I don't know what it is, and it is
quite steep, but it's not vertical.

What is the number? Why express any uncertainty? With one exception you
have full obstacle clearance at the earlist point at which a fix can be
received (i.e., considering adverse fix error).

The exception is in the non-precision final approach segment where a 7:1
gradient may, or may not, be applied to the FAF and/or some stepdown fix in
the final approach segment. A pilot has no way of determing from the
approach chart whether this design option has been applied (TERPs,
Paragraph 289).

wrote in message ...


Doug wrote:

A pilot can use either technique. Depending on the pilot, the aircraft,
and the approach, there are positives and negatives to using dive and
drive vs. stabilized constant descent technique.

The accidents stats don't support any positives for dive-and-drive.

Cite?

Matt Barrow wrote:

wrote in message ...


Doug wrote:

A pilot can use either technique. Depending on the pilot, the aircraft,
and the approach, there are positives and negatives to using dive and
drive vs. stabilized constant descent technique.

The accidents stats don't support any positives for dive-and-drive.

Cite?

How can I cite the negative? There are many, many NPA crashes over the years.