On Tue, 13 Mar 2007 21:53:19 -0500, "Stan Prevost"
wrote:


"Ron Rosenfeld" wrote in message
.. .
On Tue, 13 Mar 2007 19:31:58 -0500, "Stan Prevost"
wrote:


For an interesting GPS GP, look at the Jepp chart, if you have it, for the
RNAV (GPS) RWY 28 at KPQI. The GP starts down about 0.3 NM after the FAF.
This appears to be done in order to meet a crossing altitude restriction
insice the FAF, and still have a profile that brings you to an appropriate
height closer in to the runway.


I only have the NACO chart, and it doesn't show up that way. Shouldn't they
be the same if it is necessary to meet obstacle criteria?





I didn't think the NACO charts showed the GPS GP profile. Let me check at
KPQI ... Interesting difference.

On the Jepp chart it also shows a 3.25° GP, which intersects PESIC at
1200'.

The GP runs level from LISDE for 0.3 NM, with top of descent 4.4 NM from
HUMAX and ends at HUMAX but below the MDA.

The NACO chart also shows a 3.25° GP intersecting at PESIC at 1200', but it
appears to run smoothly from LISDE (which is 4.7 NM from HUMAX. Obviously
both cannot be correct.

Doing some trigonometry it appears the JEPP chart is correct:

PESIC--LISDE = 3.2 NM

PESIC--Top of Descent of GP = 2.9 NM (4.4-1.5)

The "triangle:


Height = 1000' (LISDE 2200- PESIC 1200)
Angle = 3.25°

Base = 1000 / tan (3.25°)

= 2.9 NM


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)