Backup plates on PDA

There have been a number of threads in this and other forums about which
approach charts to use, and about how the availability of free downloadable
charts from NACO affects the decision. Some pilots purchase full US or
regional subscriptions, others download and print just the charts they
expect to use on a flight (primary and alternate), others fret that, if they
do that, they will not have charts available for an unplanned airport should
it become necessary to divert. I have two partners in our airplane. We
have been pondering these questions also.

Two of us have been buying the full U.S. set of NACO TPPs each year through
the AirChart system. I more and more find myself always downloading and
printing new charts for every flight and taking along the AirChart TPPs for
backup (and also other info like Departure Procedures), rather than going
through the updates. Of course, I still have to check NOTAMs and update the
charts for that.

We just upgraded our AnyWhereMap system to AnyWhereWx (XM Wx) with a new
iPAQ, and we decided to try something different. The idea is to download
from NACO and print the charts for our primary and alternate airports, and
to have current backup digital charts in the iPAQ for the event of having to
use an unplanned airport. The Sporty's digital subscription is lower cost
than NACO, but I don't know how their software is for accessing the charts.
Last night I loaded Adobe Reader for Pocket PC into the iPAQ, along with a
NACO chart, and as expected the display is small, but it looks usable. With
proper choice of zoom for readability, the amount of the chart that is
visible in one view is pretty good, and doesn't require too much panning.
It certainly is not like looking at the chart through a soda straw as I
thought it might be. So now I think we will take the next step and try one
cycle of the Sporty's charts.

If this works out, it will cost considerably less than two sets of TPPs.
Actually it is less than one set of TPPs, $120 for a year's subscription, or
$9.95 per 28-day cycle. It looks like it includes full TPP info.

The full set takes 3GB of storage, but the software allows downloading
selected states. With three 1GB SD cards for the iPAQ (about $50-60 each on
sale), it might work out OK. Actually, a 1GB SD and a 1GB CF will fit in
the iPAQ simultaneously, so about 2/3 of the country can be accessible at
once. There is still about 80MB of nonvolatile storage available in the
iPAQ 4700 for programs, databases, and backup.

The downside is that the storage cards will have to be reloaded every 28
days.

Control Vision also offers their product Pocket Plates, will display
aircraft position on the chart. These charts have to be individually
georeferenced by tapping on two navaids, as I understand it, plus they are
more expensive. We will first try the Sporty's charts.

I'll report back on how this seems to work. If anyone has already tried it,
comments are welcome.

Stan