Garmin 396 Weather avoidance..

"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

Third, you need to understand that delayed weather is not a tactical
weather avoidance device.

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.

-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

On 9 Jun 2006 17:04:28 -0700, "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.

My take on this and I've been storm chasing longer than we've had
Loran, let alone down linked RADAR. I've seen 5 tornados and one
really big water spout. I even managed to get caught outdoors along
with two of my neighbors, in a little F-1 and that can certainly raise
your sense of awareness.

The 396 has some advantages and disadvantages when compared to
airborne RADAR. Starting with the good, it does not have the blind
spots you will find from time to time in airborne RADAR caused by
absorption in heavy precipitation which can hide some nasty stuff.
OTOH if you keep in mind that the display is probably 5 minutes old or
a tad more AND you have been following it you can pick your course.

However I agree with Robert. Take a conservative approach and learn to
interpret what you are seeing on the display, how to track, and how to
predict. Learn to follow both cell and frontal movement. They are
rarely the same. Usually the cells are traveling at right angles to
the front, but NOT ALWAYS. Learn to identify upper level winds by the
rain blown off creating plumes that may or may not go in the direction
of the front or cells. You normally want to stay away from those
plumes as they may contain hail and that can be as much as 5 to 10
miles ahead of the storm at altitude. Speaking of hail and altitude,
you really don't want to run into hail in front of a cell at altitude.
It is a *lot* larger than what we see at ground level.

BTW when on the ground and in front of an approaching storm. If the
wind is blowing toward the storm that is "inflow" and a sign of a
storm with very strong convective activity.

Once you learn to determine cell movement, remember that cells can
"pop up" behind the ones you are watching. Has the storm shown a
tendency for cells to pop up along, ahead of, or behind the front. Are
the cells associated with frontal movement or a general wide spread
instability?

Knowing the storm and front movement, speed and direction along with
the knowledge the information you are seeing is at least 5 minutes old
would certainly tell me I would want to give a lot of space when
flying in front of the front or cells. OTOH Cells growing up along a
line may start to pop up on the "up wind" side of current activity.
Some times the growth of this line can be a real surprise and it can
contain some really nasty stuff.

As was said earlier. Get all the information available about the
activity and area through which you will be flying. Then use that
information along with what the RADAR is showing. A storm scope can
be really helpful in extending your "real time" knowledge of what is
going on and should be a good indicator of where those RADAR images
are headed as well as what to expect from them.

Just remember that conservative approach.

-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

Yellow and even red may not indicate anything other than heavy rain if
it's not associated with convective activity. You learn what you are
seeing, where it is compared to the display, and where it is going.
Then stay out of its way. All this takes practice and liberal use of
FSS can help.

Good Luck,


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


considering the purchase of one and am wondering how to use the info
safely, but yet with the maximum utility.

Dan

Roger wrote:

On 9 Jun 2006 17:04:28 -0700, "Robert M. Gary"
wrote:


The 396 has some advantages and disadvantages when compared to
airborne RADAR. Starting with the good, it does not have the blind
spots you will find from time to time in airborne RADAR caused by
absorption in heavy precipitation which can hide some nasty stuff.
OTOH if you keep in mind that the display is probably 5 minutes old or
a tad more AND you have been following it you can pick your course.

All systems have their limitations, including airborne weather radar.
That is the reason that the prudent operation of airborne weather radar
requires minimim avoidance distances, depending upon altitude and
weather the outside air temp is above freezing.

The limitation you cite indeed exists but can be avoided through use of
distance-to-avoid parameters and not pushing the envelope to get the
mission accomplished, so to speak. The EAL wind shear crash at JFK, the
Delta L-1011 wind shear crash at DFW, and the Soutern Airways DC-9 crash
in southern Georgia all happaned when penetration rather than avoidance
was attempted..

The ideal setup in high-end aircraft today is airborne radar with the
largest feasible antenna and piped in weather radar for planning
purposes. The latter doesn't work in much of the world, though, just
like the 396 won't provide weather outside the 48 states.

On Mon, 12 Jun 2006 06:16:21 -0700, Sam Spade
wrote:

Roger wrote:

On 9 Jun 2006 17:04:28 -0700, "Robert M. Gary"
wrote:


The 396 has some advantages and disadvantages when compared to
airborne RADAR. Starting with the good, it does not have the blind
spots you will find from time to time in airborne RADAR caused by
absorption in heavy precipitation which can hide some nasty stuff.
OTOH if you keep in mind that the display is probably 5 minutes old or
a tad more AND you have been following it you can pick your course.

All systems have their limitations, including airborne weather radar.
That is the reason that the prudent operation of airborne weather radar
requires minimim avoidance distances, depending upon altitude and
weather the outside air temp is above freezing.

The limitation you cite indeed exists but can be avoided through use of
distance-to-avoid parameters and not pushing the envelope to get the

But again in the context of the OP it takes experience to realize
these things exist.

When you see a line and particularly a bow that starts out green on
your side, then yellow and then red followed by nothing it's time to
go some where else. That is no guarantee that sever weather exists
behind that line but it's a good indicator.

Like you and others have said, being conservative, using all available
information, and education are the important items.

mission accomplished, so to speak. The EAL wind shear crash at JFK, the
Delta L-1011 wind shear crash at DFW, and the Soutern Airways DC-9 crash
in southern Georgia all happaned when penetration rather than avoidance
was attempted..

When this stuff can take the "big boys" down the smaller stuff should
be some where else entirely.


The ideal setup in high-end aircraft today is airborne radar with the
largest feasible antenna and piped in weather radar for planning
purposes. The latter doesn't work in much of the world, though, just
like the 396 won't provide weather outside the 48 states.

There are areas where it won't do that good a job inside the US
either, but for the most part it can be a very useful tool,
particularly when used in conjunction with other available
information.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

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
--------------------

"Doug Vetter" wrote:
I always stay clear of red, since it's always convective.

Not always, but it is probably safest to assume it is.

--
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've had a 396 for a year, but not that much weather flying with it. I
drive a lot and it's fun to analyze from the ground.

I think one of the big dangers as mentioned here before it getting into
a rapidly building tower cumulous which might not show up if you're in
the soup with your 396. I remember in Robert Buck's book "Weather
Flying" I think he said the worst turbulence he ever experienced was
in a cloud that hadn't produced rain yet.

My solution is to try to stay either above to see the buildups, or
below and avoid the rain shafts. But the 396 can also be used to find
areas of less cloud cover and lower tops. The echo tops have that
feature where you can scroll through the altitudes and watch where
cloud appears. Then you can just look for the holes in the regular
satellite display.

So to me the trick it so combine all these: The 396 weather features,
what image ATC is painting, the overall weather picture to determine if
the ingredients for convection are there, what you see out the window,
PIREPS and ride reports, tactical weather flying to try to keep
yourself visual as much as possible. Green or yellow may be fine on
days when you know there is little chance of buildups. But if green is
next to a steep gradient of yellow, into orange to red. Steer clear.

I think the 396 is an amazing tool. You can sit on the ground in your
airplane and it's almost like having the internet in your lap. I sat
on the ramp at Midway a few weeks ago and waited for a hole in the
weather using the 396. I practice with Elite simulator which will now
drive your 396 plugged into a serial port. I can put the satellite
antenna out the window to get real weather, download through Elite and
the internet real weather, and I can do near real time weather practice
sim flying. And you get a great automotive navigator for a few extra
bucks. ... akiley

I agree completely with akiley here.

To me, the 396's value is in adding more detail to what's already
available. Especially in terms of calibrating your eyeballs. If you
try to stay in the clear as much as possible and use the 396 to add
dimensions to what you see (and hear from ATC/pireps), you'll find it a
tremendous aid.

Having said that, any hard rules about flying thru purple and never
flying thru fuscia are generalizations at best. It's all about getting
the big picture, forecasts, actual, trends, and filling in the details.
Rain in non-convective conditions is completely different from
convective rain. Sometimes the value is all about being able to see
what's going on beyond that wall of clouds in front of you.

One of my early experiences flying north out of FL into Savannah - I
swear I was doing better with the 396 than the guys with onboard radar.
What I was seeing was probably less important to them than to me but
being able to see around corners enabled me to make the best fuel stop
while they seemed more dependent on ATC advice. Pretty amazing when
compared to pre-396 days.

akiley wrote:
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.
a cloud that hadn't produced rain yet.

My solution is to try to stay either above to see the buildups, or
below and avoid the rain shafts. But the 396 can also be used to find
areas of less cloud cover and lower tops. The echo tops have that
feature where you can scroll through the altitudes and watch where
cloud appears. Then you can just look for the holes in the regular
satellite display.

So to me the trick it so combine all these: The 396 weather features,
what image ATC is painting, the overall weather picture to determine if
the ingredients for convection are there, what you see out the window,
PIREPS and ride reports, tactical weather flying to try to keep
yourself visual as much as possible. Green or yellow may be fine on
days when you know there is little chance of buildups. But if green is
next to a steep gradient of yellow, into orange to red. Steer clear.

I think the 396 is an amazing tool. You can sit on the ground in your
airplane and it's almost like having the internet in your lap. I sat
on the ramp at Midway a few weeks ago and waited for a hole in the
weather using the 396. I practice with Elite simulator which will now
drive your 396 plugged into a serial port. I can put the satellite
antenna out the window to get real weather, download through Elite and
the internet real weather, and I can do near real time weather practice
sim flying. And you get a great automotive navigator for a few extra
bucks. ... akiley

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.

I just want to add to those who suggested getting your feet wet a little at a
time and using the 396 information conservatively until you have some experience
with it:

The 396 I think still comes with the automobile kit, so on a day with some
active weather you can stick the 396 in your car and drive around looking for
interesting conditions. Its' a lot cheaper and safer to experiment in your car.

Dave