Garmin 396 Weather avoidance..

Bob Gardner wrote:

This is from WSI's web page. Note the "near real-time" qualifier and
"mosaic."

Thanks, Bob. I am aware of the limitations of this and any downlinked
RADAR mosaic. In addition to Flight Service/Flight Watch, ATC weather
radar (where applicable), and eyeballs, I do use WSI for tactical (big
picture) weather avoidance. It is because of this that I was interested in
reading of the details of this particular accident.

There seem to be some vague details in the explanation of this accident
that I would like to explore. The fact that the accident aircraft was a
C172 (TAS 125 knots) and that it flew into an area of previously
convection-free activity suggests that the downlinked RADAR data were very
stale.

I certainly don't have the experience you have, but I have seen areas go
from no precipitation to level 5 precipitation in about 15-20 minutes. Is
it possible for a strong thunderstorm cell to mature quicker than that?

WSI advertises (at least when I first bought the receiver) that the radar
download would never be more than 4 minutes old. However, add to that the
"pre-processing" that they apply to the data and perhaps the picture is up
to ten minutes old.

With my WSI install, I have experienced numerous downlink outages (which
were attributable to both WSI system outages and installation problems at
my end) and significant delays in the data of up to 25 minutes, so I
learned long ago that this tool could never be used as a replacement to
active, on-board radar for navigating through a convective line.

It is worth mentioning that when the system was working and refreshing once
every four minutes, I did find the precipitation levels seem to match that
through which I was currently flying or that which I could see in the
distance.


--
Peter