Well, let me posit a scenario.

Flight Plan:

KABC WPTA WPTB WPTC KDEF

After passing WPTB, I either conclude on my own that APPRCH 1 to KDEF is
what I expect, or I am told to expect it. So I select APPRCH1, from IAF1,
and load it. Now the flight plan is

KABC WPTA WPTB WPTC KDEF IAF1 IF FAF MAP MAHP.

I delete the destination airport which causes a discontinuity (lots of
buttons and knobs):

KABC WPTA WPTB WPTC IAF1 IF FAF MAP MAHP.

Now I am still flying with WPTC as the TO waypoint, with the next waypoint
being IAF1.

Now, Case 1: I continue flying to WPTC, on passing it the machine sequences
to IAF1. But I have not been cleared to IAF1, I am still cleared to KDEF.
Problem. Requires unexpected actions. I have to fix it by entering direct
to a waypoint not in the flight plan. Lots of button/knob actions. I'm too
lazy to type it all in.

Case 2: Before reaching WPTC, I am cleared direct to IAF1. Requires pilot
intervention: FPL, press small button to get cursor, scroll down using
large knob to IAF1, Direct, Enter, Enter, FPL. Or, FPL, press small button
to get cursor, scroll down using large knob to WPTC, CLR, ENTER, FPL.

Case 3: I continue flying original flight plan, navigator continues to
sequence along cleared flight plan until I am cleared to fly direct IAF1.
PROC, ENTER, done.

Case 4: I figure that I will get Vectors To Final. So I load the approach,
with an IAF selected or with VTF selected. I delete the destination airport
waypoint. After passing the last enroute waypoint, the machine will
sequence to the IAF, if any, or to the FAF, if VTF. Is its action
consistent with my clearance at that point? As opposed to: upon receiving
the first vector, press PROC, ENTER (if VTF was loaded, otherwise scroll to
the VTF option on the menu and ENTER).

Do these scenarios miss the point?

Stan







"Stan Prevost" wrote in message
...

"Sam Spade" wrote in message
...
Stan Prevost wrote:

FPL, push small knob to get cursor, scroll down to airport, CLR, ENTER
to confirm, FPL to get back to NAV page.

vs

PROC, ENTER.

True enough. But, the bit of extra stuff earlier on is none the less
easier and I don't have to worry about making sure I am where I am
supposed to be if I "activate."



(and from another post)
I took another look at it and disagree. Once the IAP is selected removing
the airport can be done prior to a critical phase of flight, then
everything sequences without pilot intervention

Sam, I have reread your posts trying to make sure I understand your
points. First of all, I didn't know the Garmins would self-activate, so
that is something new I have learned from this thread. More on that
later. I understand that you prefer to perform a more complex task rather
than a two-button-task if you can move the task to a less busy period of
the flight. But the "without pilot intervention" part only happens if you
were already direct to the IAF at the time you deleted the airport
waypoint, or deleted the airport waypoint to make the navigator sequence
to the IAF when instructed to proceed direct to the IAF. Either way, it
is the same result as the simpler activation procedure performed at the
same point in time. If that is not true, then I am missing something in
the scenario. Perhaps a simple example would help.

As far as I can determine, the self-activation feature is not mentioned in
the Garmin manuals. I believe another poster said the same. Personally,
I am a bit uneasy about using undocumented "features" of software in
critical situations. For one thing, we don't really know what is
happening and if it has even been tested. Does it do the required RAIM
predictions prior to the FAF? How would you know, unless it fails? Does
this "feature" work under all conditions? Another thing, you don't know
if the "feature" will still exist, or work the same way, if the software
is updated.

I wonder what the response would be if one called Garmin and asked if they
approve using the navigator this way? Or the FAA?

Stan