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

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

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

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

I wish I had an easy answer for you. However, wx is a non-trivial
subject. There are two ways you can make use of your 396 in wx. First,
you can fly with a CFI who is experienced in flying cross country.
Second you can start out very, very conservative and learn as you go
how the wx on your 396 affects your flight.

-Robert, CFI


Dan wrote:
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

"Robert M. Gary" wrote:

I wish I had an easy answer for you. However, wx is a non-trivial
subject. There are two ways you can make use of your 396 in wx. First,
you can fly with a CFI who is experienced in flying cross country.
Second you can start out very, very conservative and learn as you go
how the wx on your 396 affects your flight.

Agree.

I have a lot of hours using XmWx to dodge CBs. I have found it to be a
wonderful tool, but it is definitely something you want to ease into as you
learn how the colored blobs you see on the screen translate to what you see
out the window.

--
Dan
C172RG at BFM

Dan wrote:
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 have only been in a few such situations since I bought the 396 last
year, and my experience is that you can fly through green all day long.
Yellow is okay as well provided it's not convective (forecasts, a
nearby lightning strike or cell data icon are a few ways one may
determine that). I always stay clear of red, since it's always
convective. The deep orange color can go either way -- I remember a day
of soaking rains that were displayed as yellow and orange, but there
were no thunderstorms in the area because the temperature and
atmospheric conditions simply didn't support convection on that scale.

I have also confirmed the lag in delivery and concur with the other
poster who suggested you determine the direction of movement and
circumnavigate on the upwind side of the cells only. I was flying
commercially one day, relocating an aircraft for some jump operations,
and had to wind my way through many cells.

I expedited my departure from the Danbury, CT airport as I watched one
cell about 10NM in diameter approach the airport. The outer edges of
the cell, depicted as green, reached the edge of the airport where I was
doing my runup when light rain started. But that cell was crawling --
almost stationary.

Enroute, I watched one cell literally explode and move at better than
30K. It took a mere three updates (15min) from this to go from one
pixel, or 2sq nm green (a "harmless shower") to a cell being tracked
upwards of 25K feet with lots of red in its core. As I watched it in
real time outside the window, it was clearly several (7-10) miles ahead
of its indicated location, though the diameter of the rain shaft
appeared roughly correct.

I just flew from NJ to SC and used the 396 for its true intended purpose
-- peace of mind. I could see the top-down weather picture and make
sure that the weather was not developing outside the scope of the
forecast. That is the way the 396 weather capability should be used --
not for close-in tactical avoidance. If you want to play that game, get
on-board radar and a stormscope...and even then second guess whether you
want to fly in those conditions.

A few caveats:

Keep in mind that I've seen shower activity (level 1, maybe 2) that does
NOT show up on the Garmin AT ALL. Do not expect to use the 396 to stay
dry. For whatever reason, it doesn't work that way.

Also, the 396's lightning data is derived from a network that records
cloud-to-ground strikes only. Cloud to cloud strikes are thus not shown
on the 396 -- you need a stormscope to see those.

Hope this helps. Safe flying,

-Doug

--------------------
Doug Vetter, ATP/CFI

http://www.dvatp.com
--------------------