WAAS for GNS 430/530?

"Jon Carlson" wrote:

Does the computed glideslope indication meet obstacle clearance (i.e.
stepdown altitudes and whatnot) even if the approach is flown a couple
of dots low on the glideslope indication? Or does the pilot/autopilot
need to be absolutely sure that the approach is flown smack in the
middle or a couple dots high?

I think that's kind of like asking, "Does the MDA meet obstacle clearance
even if you go below it?".

I think the answer to both questions is the same, "There's some
TERPs-defined buffer built in, but from the pilot's point of view, all you
gotta know is don't go below what the procedure says until you can see the
runway".

I think that's kind of like asking, "Does the MDA meet obstacle
clearance
even if you go below it?".

Sort of, but one of the advantages of WAAS generated glideslopes is
that it enables autopilot coupled approaches with vertical guidance.
So... if a dot or two off runs you through a hill, that might be a
nice thing to know and correlate with your autopilot's level of
precision...


I think the answer to both questions is the same, "There's some
TERPs-defined buffer built in, but from the pilot's point of view,
all you
gotta know is don't go below what the procedure says until you can
see the
runway".

Yes, we are still responsible for not descending below the MDA. But we
need to understand the limitations of the box if we're going to let
the box help us so that we can know what we have to do to live up to
those responsibilities.

-Jon C.