WAAS GPS approach question.

On 04/20/06 15:24, wrote:
WAAS Approaches have vertical guidance but they
are not classified as "Precision"

Bill Hale


Are you sure about that? I thought the P in LPV stood for Precision?
Also, the LPV approaches have a DA rather than an MDA, which also
implies a precision approach, doesn't it?


--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

Officially, LPV refers to "Localizer Performance with Vertical
Guidance". Officially it's not precision, perhaps
not-so-non-precision. With horizontal and vertical accuracies in the
1-2m range, its arguably more accurate than a Cat III ILS. It does not
however,have the integrity of a Cat III. The LPV approach does indeed
have a decision altitude which currently is as low as 250ft HAT, and
the recent approval of 200' DA's will likely start showing up on
procedures next year.

Brad

On 20 Apr 2006 15:24:09 -0700, "
wrote:

WAAS Approaches have vertical guidance but they
are not classified as "Precision"

Bill Hale

What makes you say that. The only definition I'm aware of (in the P/CG)
only requires that the approach provide electronic vertical guidance:

"PRECISION APPROACH PROCEDURE- A standard instrument approach procedure in
which an electronic glideslope/glidepath is provided"

I might argue that an LNAV approach with "advisory" vertical guidance does
not really meet that definition, but surely an LPV approach provides
"electronic vertical guidance".
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)