On Fri, 22 Oct 2004 14:08:57 GMT, Nathan Young
wrote:

The Garmin 480 now supports LPV approaches which are ILS like
approaches using WAAS-GPS for both LNAV and VNAV.

My question. I'm assuming the LPV approach would target 1000ft down
the runway as the TDZ (just like an ILS). Does this mean that LPV
approaches will not be added to the airports with smaller runways?

For example, my homefield (3ck)has a 3058 runway. The 1000 ft TDZ
would only leave 2000 ft to get stopped, so I am wondering if an LPV
approach would ever be added at 3ck (or similar airports).

On a few LNAV/VNAV approaches I looked at, the chart was annotated with a
TCH 51'. So assuming you maintain the 3.00° glide path angle, you would
touch down approximately 973' from the runway threshold. That is also
called the Ground Point of Intercept or GPI.

The LPV approach at FDK has a TCH of 50' and a GP angle of 3° -- so it
seems that is about the same.

However, for airports served by smaller aircraft, the procedure specialists
have the option (I believe) of both increasing the GPA and decreasing the
TCH. This would decrease the GPI and allow the use of shorter runways.
How short? I dunno. It seems one could probably get a GPI of 500' or so
but I don't know what that does for minimum runway length for an LPV
approach.


--ron