The ODP out of MMK for runway 36 reads, "climbing left turn to 1800 via
325° bearing from MMK NDB before proceeding on course".

It seems to me that the easiest way to fly that with a GPS would be to
create a user waypoint which is a 325 bearing, 20 (or whatever) mile
offset from MMK NDB and insert that into your flight plan before the
first real waypoint in your clearance. Take off, track to the user
waypoint until reaching 1800, then do "direct" to the next waypoint.
Can anybody think of a good reason not to do it that way?

There are a couple ways of navigating this with the GPS, The best method
depends on what kind of GPS you are using. Here is my $.02 worth of
opinion:

If you have an IFR certified panel mounted GPS, I would execute a direct MMK
and use the OBS mode. If I read the AIM correctly, it appears that you
would have to have the CDI mode set to terminal sensitivity (normally 1 to
1.25 nm) to use the GPS for navigation without having an ADF (AIM 1-1-19f,
http://www.faa.gov/ATpubs/AIM/Chap1/aim0101.html#1-1-19). For example, on
the Garmin 400 series you would have to page 3 of the AUX menu to change the
CDI from enroute sensitivity. I would recommend displaying cross track
also. I would recommend a second opinion rather than depend on my quick
late night interpretation of the AIM.

When you are ready to go to the next waypoint in the flight plan, just
execute a direct. Depending on the GPS, it may come out of OBS mode, but
make sure that it does.


The technique that you mention should work. If you were to create a
waypoint as you say, on most GPS receivers you would want to make the first
point in the flight plan MKK and the second point the waypoint that you
create. When you activate the flight plan, the active waypoint will be the
created waypoint and MKK would anchor the first leg. The XTK value would
reference this leg. Be careful about using this technique with a VOR
because VOR's are often slightly out of alignment with magnetic north. Obvi
ously, make sure the GPS is set to reference magnetic rather than true
north.

If you are using a handheld aviation GPS with an HSI, you might consider
using the OBS and HOLD option with the 145 bearing. The needle will still
indicate the correct displacement direction even when set on the TO bearing,
but the advantage is that the line on the map will be along the 325
outbound -- better situational awareness. Obviously, the GPS would only be
for situational awareness and you would have an ADF. I tend to like data
fields and TURN, which is the difference between TRACK and BEARING, is one
of my favorites. You can use XTK (OFF COURSE on some handhelds) in
conjunction with TURN as data fields. Choose a heading to keep TURN between
L179 and R179 and make slight adjustments to XTK.

If you really want to be adventurous, just execute a direct to MKK. Moving
clockwise causes the bearing to increase and counterclockwise causes it to
decrease. Since the GPS bearing is the bearing TO, you would want to fly
outbound so that the GPS bearing was equal to 145. Once established, you
can use TRACK to help stay on course.

John Bell
www.cockpitgps.com