John R. Copeland wrote:
"Sam Spade" wrote in message ...

John R. Copeland wrote:


"Sam Spade" wrote in message ...


With LPV, the sensitivity continues to increase (course width decreases)

from the FAF to the runway. That causes LPV to be an angular system
from the FAF to the runway. Not so with other RNAV.


Thanks. I didn't know of the difference. I'll watch for it.


I getting up to speed on the 145/146 spec. The LNAV approach also
reduces in the lateral mode similar to the laternal mode of the LPV
approach. When you reach the MAP, it is only 350 feet full scale
deflection, instead of the 0.3 mile defection for TSO 129 LNAV final.


I'm definitely gonna have to set up an experiment over that!
I'd expect to have noticed it, if my CNX80 behaved that way.
Is that a behavior demanded by TSO-C145/146, or merely allowed?


The following language suggests that LNAV must always be 350 feet at the
MAP. Both Figures 2-12 and 2-13 show 350 at the MAP.

2.2.3.3.1 Approach Path Definition

If the pilot has not selected a VTF approach, deviations shall be
provided with respect to the active leg of the approach procedure. See
Figure 2-12. If the pilot has selected a VTF approach, deviations shall
be provided relative to the inbound course to the FAF. See Figure 2-13.
The active waypoint shall initially be the FAWP. The equipment should
also account for short turns onto the final approach where the FAWP may
not be crossed.

Note 1: A VTF approach can be selected at any time.