How did I survive without on board weather?

[swingwing]

I did three "light" IMC flights this weekend and I feel so much safer flying with nexrad weather on the handheld gps. It is really nice to get a picture of the weather that the controller is vectoring you around. It has been the most useful upgrade to my steam gauge slant alpha cockpit. I'm not sure I would fly blind anymore without it.

 

[nyoung]

Agree 100%.

I did three "light" IMC flights this weekend and I feel so much safer flying with nexrad weather on the handheld gps. It is really nice to get a picture of the weather that the controller is vectoring you around. It has been the most useful upgrade to my steam gauge slant alpha cockpit. I'm not sure I would fly blind anymore without it.

 

[dmccormack]

Yep -- agreed -- especially flying blind with potential embedded CB.

Stay tuned for the obligatory "YOU CAN'T USE JUST XM WEATHER!" posts to follow... B)

(Of course, flying IMC in areas of convective activity, XM with StormScope or other sferics device should be minimum equipment, IMHO)

 

[PittsDriver]

XM isn't the only thing to use but it's definitely a game changer.

 

[jtheune]

Does the lightening strike information have the same time lag issues as the radar?

 

[Areeda]

Does the lightening strike information have the same time lag issues as the radar?

Pretty much.

XM is very useful, I love it. Like any tool it has appropriate and inappropriate uses. My favorite use is on a long cross country you can see an issue on your route and divert a few degrees adding very little time to the whole flight. Whereas flying up to a storm and flying around it is very inefficient.

IMHO it should not be used to penetrate storms but rather to avoid them.

Joe

 

[nyoung]

I believe so. The issue is that the weather provider has to assemble the weather information, send it to XM, get uplinked to the satellite, and then broadcast on the XM channels.

I don't know how long the first 3 steps take, but the last step is (relatively) time consuming (several minutes). I used to have an WxWorx box that displayed XM WX on a PC. Their application dumped the data stream from the XM radio into a series of files on the PC. It took several minutes for the XM radio to receive an entire library of info before starting the next/new library.

Does the lightening strike information have the same time lag issues as the radar?

 

[FlyerJosh]

Yep -- agreed -- especially flying blind with potential embedded CB.

Stay tuned for the obligatory "YOU CAN'T USE JUST XM WEATHER!" posts to follow... B)

(Of course, flying IMC in areas of convective activity, XM with StormScope or other sferics device should be minimum equipment, IMHO)

I'll be the first to say it... :wink2:

I love XM, but having seen how large a difference there can be between onboard weather radar and XM, I use XM wholly as a "strategic tool" for avoiding weather by large margins.

Remember that in addition to the satellite/transmission lag inherant to XM, there is also an additional 5-10 minute delay due to the nature of how NEXRAD images are compiled and transmitted. For those of you who don't know, XM transmits the NEXRAD Composite image, which is a series of vertically stacked "slices" of radar data. Each composite image consists of however many slices it takes to "paint" the weather from top to bottom. Since each slice requires one full rotation of the radar antenna, a very large cell may take several minutes to compile the data.

Even if the XM says you have data that is less than one minute old, part of what you're looking at is at LEAST 5 minutes old. When dealing with heavy convective activity(tops above 30K), that's significant. Remember that storms have been recorded with growth of up to 6000 FPM and groundspeeds in excess of 60MPH. A LOT can change in a few minutes.

It's a good tool, but recently I've met some pilots with G1000 equipped aircraft that are flying hard IMC around severe weather using only XM as their source for weather. That's a good way to end up scattered across a large swath land when you encounter 6000+ FPM shears inside an imbedded cell.

 

[Ted]

IMHO it should not be used to penetrate storms but rather to avoid them.

100% agree. I have both XM and on-board radar. I'll use the XM for wide area awareness and to get a general idea of what's going on. However yesterday I penetrated a tiny hole to get into my airport (ended up making a visual approach, even), but I used the on-board Sanford & Son radar to do so. The XM gave me general idea of what was going on, and the Sanford & Son radar showed me this nice hole to fly through. Worked great. Wouldn't have done it with XM only.

 

[SCCutler]

In my limited experience with XM (and why have I not yet bought mine? Indecision as to which platform to get, that's why), I find that the XM for strategic use (as described above), and the unmatched combination of Mk. I Eyeballs and StrikeFinder for up closer, all seems to work well.

 

[tonycondon]

i would've liked to have XM for gastons weekend, or any of my trips home to see parents and etc. but instead i have gone old school and resorted to flight service, 122.0, center, and eyeballs.

 

[dmccormack]

i would've liked to have XM for gastons weekend, or any of my trips home to see parents and etc. but instead i have gone old school and resorted to flight service, 122.0, center, and eyeballs.

I've had to do that a few times and gotta say -- nothing is as easy as looking at a map with an overlay.

Flight Service telling me "Convective activity along a line between Syracuse and Atlanta" just isn't that helpful.

 

[dmccormack]

I'll be the first to say it... :wink2:

I love XM, but having seen how large a difference there can be between onboard weather radar and XM, I use XM wholly as a "strategic tool" for avoiding weather by large margins.

Yep -- this topic should have the dead horse flag...

Anyway, you'll see I mentioned 'sferics in conjunction with XM.

 

[tonycondon]

I've had to do that a few times and gotta say -- nothing is as easy as looking at a map with an overlay.

Flight Service telling me "Convective activity along a line between Syracuse and Atlanta" just isn't that helpful.

it is important to ask the right questions and get clarification. but flight service is just one datapoint. combined with what center (or preferably, approach) sees on their radar plus what you see outside the window, can make for a pretty complete picture.

I flew with XM all the time when I was in college and flying charters. I don't disagree that it is choice but successful IFR flying is certainly possible without it.

 

[Ted]

Also keep in mind there are lots of places where you don't get XM at all. Where I went in Canada this weekend I got satellite overlay, but no radar whatsoever. Forget about weather reporting stations, there aren't any airports to report. Oh, and you can't even get Quebec radio on th radio in some places, so forget about getting much in the way of help. Eyedar, on-board radar, that's what you got. Work with it and make decisions accordingly.

 

[mantakos]

Does the lightening strike information have the same time lag issues as the radar?

There is an inherent time lag in the sense that your data cannot be any fresher than the time since the last periodic broadcast. In the cast of lightning and XM, this is 5 minutes.

But there are some lags that are unique to the process of collecting Nexrad radar, because it is generated from a physical device that takes real time to "sweep" the sky and has to repeat this process at multiple elevations. I don't think there's any corresponding delay in collection of lightning data, though I've never seen any description of what that process looks like.

So, yes, there's a delay, but there's reason to believe that the delay SHOULD be shorter than for Nexrad.
-harry

 

[dmccormack]

it is important to ask the right questions and get clarification. but flight service is just one datapoint. combined with what center (or preferably, approach) sees on their radar plus what you see outside the window, can make for a pretty complete picture.

I flew with XM all the time when I was in college and flying charters. I don't disagree that it is choice but successful IFR flying is certainly possible without it.

Oh, absolutely!

But I have a motorcycle and a bicycle. Guess one is easier to ride?

 

[jtheune]

That is what I thought should be the case as well. I looked at the xm web site and could not find that level of detail about it. I have a 69gdl attached to my 530 but my partnership only gets the aviator lite sub so I don't have the lightening info nor some of the other goodies.

 

[vontresc]

I would have loved to have XM on my way home. Mainly because I had to listen to some VFR bonanza driver monopolizing Flightwatch for like 20 minutes...

 

[tonycondon]

I would have loved to have XM on my way home. Mainly because I had to listen to some VFR bonanza driver monopolizing Flightwatch for like 20 minutes...

i had the same issue so i found a local flight service frequency that was clear. it was a little difficult hearing everything the FSS guy was saying though as he was stepped on at least twice by a Cirrus pilot trying to get ahold of him. apparently he didnt have the volume turned up.

 

[poadeleted20]

To answer the title question, my luck bag was a lot fuller back then than it is now. Fortunately, here in the 21st century, pilots have available the tools to rely more on technology than luck in surviving the process of filling their experience bags.

 

[Everskyward]

I've had to do that a few times and gotta say -- nothing is as easy as looking at a map with an overlay.

I've never flown a small airplane with XM weather and a larger airplane only once. I can see how it would be a nice tool, however.

 

[dmccormack]

I've never flown a small airplane with XM weather and a larger airplane only once. I can see how it would be a nice tool, however.

It's odd, but I think small, slow airplanes need XM more than fast twins and jets. After all, during a 3-5 hour XC the weather can change significantly when you're averaging 110 knots, and we're usually slogging along in the middle of the stuff.

 

[Everskyward]

It's odd, but I think small, slow airplanes need XM more than fast twins and jets. After all, during a 3-5 hour XC the weather can change significantly when you're averaging 110 knots, and we're usually slogging along in the middle of the stuff.

Jets do 3-5 hour legs too, they just go further in that time.

I do agree that they get to fly above the weather more when enroute but there's always the departure and the arrival. Also they tend to fly in worse weather because they are capable of it, besides they pretty much all have onboard radar.

 

[sba55]

Does the lightening strike information have the same time lag issues as the radar?

I guess both NEXRAD and lightening data is broadcast every 5 minutes now, but didn't lightening data used to be broadcast every minute? That seems much more useful to me. Why the change? Bandwidth issues?

 

[swingwing]

100% agree. I have both XM and on-board radar. I'll use the XM for wide area awareness and to get a general idea of what's going on. However yesterday I penetrated a tiny hole to get into my airport (ended up making a visual approach, even), but I used the on-board Sanford & Son radar to do so. The XM gave me general idea of what was going on, and the Sanford & Son radar showed me this nice hole to fly through. Worked great. Wouldn't have done it with XM only.

Ted:
That may have been the same storm I flew around. I departed IPT around noon and something substantial was moving in from the west.

Thanks to ever one for the responses. XM has its limitations and really has not changed how I fly. It does make me feel a lot safer having a better picture of what I'm dealing with.

 

[mantakos]

I guess both NEXRAD and lightening data is broadcast every 5 minutes now, but didn't lightening data used to be broadcast every minute?

Digging around, it looks like lightning has been a 5 minute update for at least 3 years now. I can't find any record from before then. I don't actually recall it ever being different from that, but my memory could be wrong.

They do have "storm track" which updates every 1.25 minutes.
-harry

 

[flyersfan31]

I've been fortunate to have had XM/equivalent in every aircraft I've owned, even the humble Sundowner (via 396). I'm not a bold pilot, so I use it to tell me where not to go, and when to fly carefully. I would say that, as a result of several flights where I have flown weather armed with only XM and Stormscope, I really would like radar. If I still had the Sundowner, it would be pointless, but the Matrix can cover a lot of ground and radar would be a very useful addition. Not to thread needles -- I've done that, and it's a lot of no fun. I would rather have as much information as I possibly can.

 

[ArrowFlyer]

I have a question for you seasoned pilots and weather watchers. The DA40 that I fly has lightning detection on the GNS530. Is it really necessary to add the XM WX on top of that? While I was returning Saturday on a flight, I saw some lightning on the 530's map out to the NW that I knew wouldn't affect my flight. I have a iPad that I use for its moving map functionality but I wonder if I wouldn't be better off looking at a used 396 for the benefit of adding the XM weather. During my training, my CFII would religiously bring his 496 along when the conditions were favorable for t-storms. Of course, my training was being done in a Cessna 150 and 172 which doesn't have the GNS530.

John

 

[Ted]

XM is another tool on top of your stormscope that helps you detect where not to fly. Sometimes you can have heavy precipitation that is just that - heavy precipitation. There's a whole combination of things that make an area good or bad to fly through.

"Really necessary" I don't know about, but I think it's a good tool to have. Right now I fly with XM and on-board radar. No stormscope, but that's on the list of things I want to add.

 

[ArrowFlyer]

Ted and Scott,

Thanks for the replies. Scott I am heading to your site now to sign up for your newsletter, etc. Probably very valuable information that I will have available to me.

John

 

[intubatmd]

Frankly, the $30 some odd bucks a month I pay for the XM Aviator Light is some of the best aviation money that I have spent so far. This weekend I flew down to the Outer Banks using my new IR. On the trip down there was a nice big cell over HPW. I asked for a deviation 30 some miles out to get a jump on things since I only have 160 ponies up front. Coming home yesterday I again had a deviation west of activity over HPW. It was interesting to see the stuff on the screen and then look out the window to compare the two. I was able to slip into the field just ahead of another cluster. For me, a new IR pilot, the ability to have a general picture of what is ahead really helps me stay ahead of the airplane.

 

[Ted]

Just make sure you realize the limitations of the system. XM is not on-board radar, and shouldn't be treated as such. It gives you the big picture. On-board radar tells you where that cell is real time so that you can thread the needle.

I fly with both, and am happy about that. If I had to pick one, though, it'd be on-board.

 

[Sticky1]

New to this XM stuff..... Can one get cloud bases and tops on XM

 

[Sticky1]

Sort of. First, XM-delivered satellite weather provides PIREPs. So you can gain a bit of knowledge there if pilots are reporting tops/bases (MSL). Second, you have the ability to see an echo tops product. These are not cloud tops, however. They report the MSL altitude (at 5,000 ft increments) where the reflectivity is 18 dBZ or greater and has some important limitations as I discuss in this workshop. Third, you can get bases of the clouds by looking at surface observations (METARs). Fourth, an infrared satellite image is available that can provide information on the tops of clouds in 5,000 ft increments. This product also has some important limitations as I describe in this workshop.

And during the winter, the Current Icing Product (CIP) might give you some information on the top of the icing layer which also may be associated with the tops of clouds in some circumstances. CIP is part of their premium service, Aviator Pro. Lastly, AIRMET Zulu in some circumstances can give you some help with tops as well during the winter months in the same way that CIP can help.

So I gather there isn't a good way of getting good information on cloud tops and bottoms.

Metars and TAF run up to and over an hour late. NO GOOD...proven last week on my trip back from Fla to NY.

In all I am not impressed with what XM delivers.

On a side note, why would the receiver loose the initalization signal from XM..? The efis tells me that the signal is good and I have a lock; however no info...I have to re-register when I power up the plane.

 

[Ted]

So I gather there isn't a good way of getting good information on cloud tops and bottoms.

Metars and TAF run up to and over an hour late. NO GOOD...proven last week on my trip back from Fla to NY.

In all I am not impressed with what XM delivers.

I've flown probably about 500 or 600 hours with XM. If you're not impressed with what it delivers, then you probably had too much in the way of expectations on it or else relied on it too much. It's a tool just like anything else. I've found the data is typically just as up to date as what flight service offers me, and I can get it quicker and graphically.

Know its limits and it's fine. If you're relying on it as a necessary item, then of course you're going to be disappointed. I use it as another source of info to piece together with everything else I have. It is not a no-go item for me, I have flown without it plenty since I bought it. However I do like having it along.

On a side note, why would the receiver loose the initalization signal from XM..? The efis tells me that the signal is good and I have a lock; however no info...I have to re-register when I power up the plane.

Now that is a complaint I've had. Since my XM is an external unit, I've just unplugged it and plugged it back in. But that is something I'm confused about, seems to have gotten worse in the past few months.

 

[Ted]

That's about the best you are going to do with cloud bases...and that's not necessarily a shortcoming of XM-delivered weather. You'd have that same issue if you used ADDS.

...or Center. They frequently give you hour-old information, too.

One of my students is a big fan of his XM weather. While out flying he was using it to get airport weather instead of the AWOS, so I just turned the power off on it and told him to tune in the AWOS. All in how you use it, just like anything else.

 

[azure]

METARs and TAFs get transmitted every 12 minutes. So, if there's a change to the METAR (a SPECI gets issued for example), it will be broadcast within 12 minutes or less. But it depends on the observation. If there's no change that crosses over the SPECI criteria, then it won't be updated until the next regular observation happens about 55 minutes past the hour.

METARs that are only reported on ATISes are only updated once an hour, yes (except for SPECIs)... but what about the many automated AWOSes such as (locally here) at KVLL, KPHN, KOZW? On both WSI and SkyVector they seem up be updated three times an hour. That's just an observation, but it seems as if new observations are transmitted fairly frequently. I wonder if I misunderstood what you were saying?

Not that this is necessarily relevant to the XM discussion as I haven't made a point to check how often they're updated on XM.