Garmin 396 Weather avoidance..

For those of you with a Garmin 396, how do you avoid dangerous weather,
avoid yellow and steer clear of the lightning strike indications? I am
considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan

The first thing you need to understand is that the weather you see on the
396 is several minutes old...possibly as much as eleven minutes. So you need
to watch the display and figure out which way the echoes are going, and plan
on passing them on the upwind side. Then you need to realize that radar
reflects only decent size rain droplets, not vertical currents, not the tops
of clouds, not turbulence. Bottom line is: Stay well clear of anything
green...yellow and red go without saying. If you have to get into the green,
make the incursion as short as possible.

Saw a revealing presentation at a NATCA controller's conference. They showed
a slide with several large cells being displayed, and indicated the position
of a 172 when the scenario began. The pilot told the controller that if he
could have a certain heading, he would be clear of the cell he saw on his
screen and could proceed to his destination. Unfortunately, by the time he
got to the geographical area which was nice and clear on his cockpit display
at the time he asked for the heading, the cell had moved directly into his
path with predictable results. The message to the controllers in attendance
was "What the pilot sees in the cockpit and real life are two different
things."

Bob Gardner

"Dan" wrote in message
oups.com...

For those of you with a Garmin 396, how do you avoid dangerous weather,
avoid yellow and steer clear of the lightning strike indications? I am
considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan

Bob Gardner wrote:

Saw a revealing presentation at a NATCA controller's conference. They showed
a slide with several large cells being displayed, and indicated the position
of a 172 when the scenario began. The pilot told the controller that if he
could have a certain heading, he would be clear of the cell he saw on his
screen and could proceed to his destination. Unfortunately, by the time he
got to the geographical area which was nice and clear on his cockpit display
at the time he asked for the heading, the cell had moved directly into his
path with predictable results.

Do you have an NTSB report or an approximate date of this accident? As a
pilot of an aircraft equipped with in-cockpit WSI weather, I am interesting
in reading more of the details surround it.


--
Peter

No. The presentation was by the head man at the Air Safety Foundation,
though, and if you go to their web page you may be able to find it...or ask
them.

Bob Gardner

"Peter R." wrote in message
...
Bob Gardner wrote:

Saw a revealing presentation at a NATCA controller's conference. They
showed
a slide with several large cells being displayed, and indicated the
position
of a 172 when the scenario began. The pilot told the controller that if
he
could have a certain heading, he would be clear of the cell he saw on his
screen and could proceed to his destination. Unfortunately, by the time
he
got to the geographical area which was nice and clear on his cockpit
display
at the time he asked for the heading, the cell had moved directly into
his
path with predictable results.

Do you have an NTSB report or an approximate date of this accident? As a
pilot of an aircraft equipped with in-cockpit WSI weather, I am
interesting
in reading more of the details surround it.


--
Peter

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



Bob



"About WSI InFlight
The WSI InFlight system continuously broadcasts near real-time WSI aviation
weather information directly to the cockpit using a geo-synchronous
satellite service. Information includes current observed and forecast
conditions, as well as WSI NOWrad®, a high quality mosaic of the NEXRAD
Doppler radar system. WSI InFlight has complete, uninterrupted continental
United States signal reception at any altitude. The system features a
sophisticated 'high glance' value user interface that is easy to interpret
and thereby increases situational awareness. WSI aviation weather data is
provided on an 'always on' basis for a low cost, flat-fee subscription."

"Peter R." wrote in message
...
Bob Gardner wrote:

Saw a revealing presentation at a NATCA controller's conference. They
showed
a slide with several large cells being displayed, and indicated the
position
of a 172 when the scenario began. The pilot told the controller that if
he
could have a certain heading, he would be clear of the cell he saw on his
screen and could proceed to his destination. Unfortunately, by the time
he
got to the geographical area which was nice and clear on his cockpit
display
at the time he asked for the heading, the cell had moved directly into
his
path with predictable results.

Do you have an NTSB report or an approximate date of this accident? As a
pilot of an aircraft equipped with in-cockpit WSI weather, I am
interesting
in reading more of the details surround it.


--
Peter

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

Bob,

I would think some green would be OK if not convective (even yellow
perhaps if it is simply a heavy rain)

How can the lightning info be used? There are two types of weather
packages avaliable for the 396. One is more expensive, but includes
lightning.

Dan





Bob Gardner wrote:
The first thing you need to understand is that the weather you see on the
396 is several minutes old...possibly as much as eleven minutes. So you need
to watch the display and figure out which way the echoes are going, and plan
on passing them on the upwind side. Then you need to realize that radar
reflects only decent size rain droplets, not vertical currents, not the tops
of clouds, not turbulence. Bottom line is: Stay well clear of anything
green...yellow and red go without saying. If you have to get into the green,
make the incursion as short as possible.

Saw a revealing presentation at a NATCA controller's conference. They showed
a slide with several large cells being displayed, and indicated the position
of a 172 when the scenario began. The pilot told the controller that if he
could have a certain heading, he would be clear of the cell he saw on his
screen and could proceed to his destination. Unfortunately, by the time he
got to the geographical area which was nice and clear on his cockpit display
at the time he asked for the heading, the cell had moved directly into his
path with predictable results. The message to the controllers in attendance
was "What the pilot sees in the cockpit and real life are two different
things."

Bob Gardner

"Dan" wrote in message
oups.com...

For those of you with a Garmin 396, how do you avoid dangerous weather,
avoid yellow and steer clear of the lightning strike indications? I am
considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan

I'm not a weather radar expert, although I have attended Dave Gwinn's
seminars on the subject. The presence of lightning means thunderstorm. In
fact, NWS people will not positively say "thunderstorm" until they have seen
lightning. So I would stay far, far away from lightning. One of the causes
of lightning is the imbalance of charges built up when air masses move in
opposite directions...like up and down.

Pure green with no yellow or red? Sure, thats plain precip. Maybe I was too
graphic in my earlier post.

The Air Safety Foundation has some dandy DVDs on this subject.

Bob



"Dan" wrote in message
ups.com...
Bob,

I would think some green would be OK if not convective (even yellow
perhaps if it is simply a heavy rain)

How can the lightning info be used? There are two types of weather
packages avaliable for the 396. One is more expensive, but includes
lightning.

Dan





Bob Gardner wrote:
The first thing you need to understand is that the weather you see on the
396 is several minutes old...possibly as much as eleven minutes. So you
need
to watch the display and figure out which way the echoes are going, and
plan
on passing them on the upwind side. Then you need to realize that radar
reflects only decent size rain droplets, not vertical currents, not the
tops
of clouds, not turbulence. Bottom line is: Stay well clear of anything
green...yellow and red go without saying. If you have to get into the
green,
make the incursion as short as possible.

Saw a revealing presentation at a NATCA controller's conference. They
showed
a slide with several large cells being displayed, and indicated the
position
of a 172 when the scenario began. The pilot told the controller that if
he
could have a certain heading, he would be clear of the cell he saw on his
screen and could proceed to his destination. Unfortunately, by the time
he
got to the geographical area which was nice and clear on his cockpit
display
at the time he asked for the heading, the cell had moved directly into
his
path with predictable results. The message to the controllers in
attendance
was "What the pilot sees in the cockpit and real life are two different
things."

Bob Gardner

"Dan" wrote in message
oups.com...

For those of you with a Garmin 396, how do you avoid dangerous weather,
avoid yellow and steer clear of the lightning strike indications? I am
considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan

Bob,

Was this a center or approach control facility and more
specifically, was the weather info display primary or
NEXRAD? If NEXRAD, did they discuss the amount
of delay in the weather info on the controller's display? I'm
wondering if it is significantly shorter? I know the satellite
broadcast distribution adds some additional delay, but as I
undersrand it, NEXRAD radar systems take a few minutes
to build the composite view from several sweeps. Point is,
the controller's display may be a few minutes old as well.

Also, as you point out, the weather chances quickly and
the radar is only showing precip. Thus, it is not showing
the radid air currents of a developing storm. Until you have
experienced being sucked up into a radily developing convective
storm by flying through an area that your StrikeFinder and ATC
agreed was the best path, you don't fully appreciate how danerous
this type of weather can be.

I second your recommendation to stay well clear of this type of
weather.

Ronnie


"Bob Gardner" wrote in message
. ..
The first thing you need to understand is that the weather you see on the
396 is several minutes old...possibly as much as eleven minutes. So you
need to watch the display and figure out which way the echoes are going,
and plan on passing them on the upwind side. Then you need to realize that
radar reflects only decent size rain droplets, not vertical currents, not
the tops of clouds, not turbulence. Bottom line is: Stay well clear of
anything green...yellow and red go without saying. If you have to get into
the green, make the incursion as short as possible.

Saw a revealing presentation at a NATCA controller's conference. They
showed a slide with several large cells being displayed, and indicated the
position of a 172 when the scenario began. The pilot told the controller
that if he could have a certain heading, he would be clear of the cell he
saw on his screen and could proceed to his destination. Unfortunately, by
the time he got to the geographical area which was nice and clear on his
cockpit display at the time he asked for the heading, the cell had moved
directly into his path with predictable results. The message to the
controllers in attendance was "What the pilot sees in the cockpit and real
life are two different things."

Bob Gardner

"Dan" wrote in message
oups.com...

For those of you with a Garmin 396, how do you avoid dangerous weather,
avoid yellow and steer clear of the lightning strike indications? I am
considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan

Honestly don't know whether it was Center or terminal, but I suspect that it
was Center. The whole discussion was about delays. In precipitation mode,
the image is updated every 4 to 6 minutes. This link gives the NWS
explanation of NEXRAD.
http://weather.noaa.gov/radar/radinfo/radinfo.html. The WARP (Weather and
Radar Processor) system, which is the weather display at Center consoles,
suggests further delays as the radar information is processed (duh). I have
been beating the drums, writing letters to the editor, etc, to try to
eliminate the phrase "real-time weather" from articles and advertisements.
NO ONE gets real-time weather, not even the folks at the NWS radar sites.

Because the presentation was by the Air Safety Foundation, you might find
more info on their web site.

Bob


"Ronnie" wrote in message
. com...
Bob,

Was this a center or approach control facility and more
specifically, was the weather info display primary or
NEXRAD? If NEXRAD, did they discuss the amount
of delay in the weather info on the controller's display? I'm
wondering if it is significantly shorter? I know the satellite
broadcast distribution adds some additional delay, but as I
undersrand it, NEXRAD radar systems take a few minutes
to build the composite view from several sweeps. Point is,
the controller's display may be a few minutes old as well.

Also, as you point out, the weather chances quickly and
the radar is only showing precip. Thus, it is not showing
the radid air currents of a developing storm. Until you have
experienced being sucked up into a radily developing convective
storm by flying through an area that your StrikeFinder and ATC
agreed was the best path, you don't fully appreciate how danerous
this type of weather can be.

I second your recommendation to stay well clear of this type of
weather.

Ronnie


"Bob Gardner" wrote in message
. ..
The first thing you need to understand is that the weather you see on the
396 is several minutes old...possibly as much as eleven minutes. So you
need to watch the display and figure out which way the echoes are going,
and plan on passing them on the upwind side. Then you need to realize
that radar reflects only decent size rain droplets, not vertical
currents, not the tops of clouds, not turbulence. Bottom line is: Stay
well clear of anything green...yellow and red go without saying. If you
have to get into the green, make the incursion as short as possible.

Saw a revealing presentation at a NATCA controller's conference. They
showed a slide with several large cells being displayed, and indicated
the position of a 172 when the scenario began. The pilot told the
controller that if he could have a certain heading, he would be clear of
the cell he saw on his screen and could proceed to his destination.
Unfortunately, by the time he got to the geographical area which was nice
and clear on his cockpit display at the time he asked for the heading,
the cell had moved directly into his path with predictable results. The
message to the controllers in attendance was "What the pilot sees in the
cockpit and real life are two different things."

Bob Gardner

"Dan" wrote in message
oups.com...

For those of you with a Garmin 396, how do you avoid dangerous weather,
avoid yellow and steer clear of the lightning strike indications? I am
considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan