Sandel RMI problem

My #2 RMI pointer on the Sandel would not point to GPS #2. When I had it checked at JA Air Center I was told that Cirrus says that GPS #2 is not hooked up to the Sandel. You can only get VOR #2 on the Sandel RMI #2. As I read the POH, p.3 & 4 of the Sandel Supp. you should be able to get GPS # 2. Does anyone else with the Sandel find this to be true?

My Sandel RMI #1 is connected to the VOR and RMI #2 is connected to GPS 1. I want to have this changed myself to RMI #1 connected to GPS 1, and RMI #2 connected to GPS 2. I think this would be a much better arrangement.

Our Sandel is wired the same way as Jim’s. I like it this way so I have a vor to go to if it is part of theapproach or missed approach. It is a great check and balance to have in case the sattelites fall out of the sky or go casters up.

Certainly not a bad idea, but my rationale is that if I’m using the VOR or ILS, I’ll have the CDI tuned to that. I’d like the flexibility of having a different box pointing to a different place rather than my primary navigation source. This would be great say for the outer marker for example via GPS #2. I’ll always know where I am. Another example would be the runway threshold using GPS #2. I can setup lots of scenarios with GPS 2 that don’t affect my primary navigation plan on GPS 1.

According to the POH you should be able to select VOR1, VOR2, GPS1 or GPS2 on either bearing pointer by pushing the “BRG” button and making a selection. My problem is I cannot select GPS2 on RMI2 because the wiring to do that was not installed by Cirrus. Does any other SR22 owner have the same problem. In other words, can you select GPS2 for bearing pointer #2?

In my Sandel equipped SR20, RMI #1 is the VOR from GPS #1 and RMI #2 is the GPS waypoint from GPS #1. GPS #2 is NOT connected to the Sandel.

James: I am expecting delivery of my SR22B next January or February. Officially it is supposed to be February, but Sherry Reynolds says January is possible. Thus, I can’t speak from personal experience on this topic.

However, there is considerable detailed information on this topic on the Sandel web site. Specifically, Sandel has posted the entire installation manual (current is Revision G(2)) which includes installation wiring diagrams.

According to Sandel, in a dual GNS 430 single Sandel SN 3308 install, pin 46 of P4001 of the #1 430 which is the GPS 429 out A goes to pin 10 of P3 of the 3308, pin 47 of P4001 of the #1 430 GPS 429 out B goes to pin 28 of P3 of the 3308.

Then pin 46 of P4001 of the #2 430 which is the GPS 429 out A goes to pin 26 of P3 of the 3308 and pin 47 of P4001 of the #2 430 goes to pin 7 of P3 of the 3308.

In other words, both GPS a&b outputs of both GNS 430 go to the Sandel 3308.

It appears from your post that Cirrus has only connected pins 46 and 47 of the #1 430 and has not connected pins 46 and 47 of the #2 430.

There is a serious lack of functionality by failing to make the necessary data connections. I do not intend to accept my SR22B without functionality of the #2 GPS as a source for either RMI pointer.

For further information on this, download the Sandel Installation Manual Revision G(2) and look at page 124 which is the Single SN3308/Dual GNS 430 wiring diagram. It is further identified as document #90106-10, sheet 25 of 28.

There is a similar circumstance going on with regard to the connections between the Goodrich WX500, the #1 GNS 430, and #2 GNS 430.

Here, Sandel specifies that the RS232-TX output which is pin 20 of J3 of the WX500 is connected in parallel to the RS232Rx pin of the #1 GNS 430 (pin number is missing from the drawing), the RS232Rx pin of the #2 GNS 430 (pin number is missing from the drawing) and pin 32 of P3 of the SN 3308 (by way of the data loader jack).

For further information on this, see the same Sandel Installation Manual at page 107, bearing document # 90106-10 sheet 8 of 28.

I have specific information by way of COPA Response that Cirrus has not followed the Sandel Installation Manual and has omitted the connections from the WX500 to either of the Garmin 430’s.

The result of this omission is that Stormscope data cannot be displayed on the “Weather” page of either GNS 430.

I likewise will not accept delivery of my SR22B until the Stormscope data displays on both of the GNS 430’s.

Sandel has specified three devices to be driven by the RS232-TX Stormscope data. According to information by way of COPA Response, there is no technical reason why the Stormscope data cannot display on the ARNAV, the #1 GNS 430, the #2 GNS 430 and the Sandel SN3308.

Both of these problems can be fixed by probably a few feet of #24 wire.

In both instances, the “receiving” device is set up to display the data.

In the case of the
SN 3308, there is a sub menu accessible by the switches on the front of the SN 3308 that is supposed to be able to bring in the #2 GPS data to either RMI pointer. For the want of the wire, it doesn’t work.

In the case of the Stromscope, if you look at the “Weather/Traffic” supplement to the GNS 430 pilot operating guide, you will see that Garmin spent considerable effort and software development time in working out the display of Stormscope data on their GNS 430. For the want of the wire, it doesn’t work.

Is there some shortage of #24 avionics grade wire in Duluth? We should insist that all data display options of all installed avionics are operational. If you have already taken delivery, you should insist that Cirrus make all data display functions of all installed avionics operate as the manufacturer intended.

There may be other problems out there. I do have assurance that the marker beacon outputs from the Garmin audio panel to the Sandel SN 3308 should be operational.

Anybody know of any similar problems not discussed here?

You should be able to change those selections by pushing the BRG button and changing the selection.

Actually I can’t. The #2 GPS on my plane is not connected to the Sandel at all.

Does this mean that I can have the #2 GPS connected to my Sandel and my Stormscope connected to my Garmins through a warranty repair? Is this a good COPA issue to tackle?

I have no reason to doubt the veracity of your comments about what can (and in your opinion should) be displayed on various instruments. I can only say that as someone who routinely flies in Midwest Thunderstorm country that the Stormscope display on the ARNAV is wonderful. The display on the Sandel is also helpful but I think that the screen display on the 430s is so small by comparison (especially if you use the data fields) that displaying the Stormscope data there as well is probably not going to be too useful. When you put the 430 display on, say, 100 miles, you will have a hard time interpreting the strikes in relation to your planned route. Everything is just going to be too close together. The ARNAV display is hugh by comparison and is really the ideal way to display this data.
I must confess that since picking up my 22 in July I have come to use the 430s to enter my flight plan and communicate. I rarely use the map feature in flight (in fact I keep the flight plan page of #2 open all the time) but rather use the RNAV and Sandel for my map and situational awareness. Prior to getting the 22 I thought the ARNAV was going to be superfluous and that all I would need were the 430s. I no longer feel that way and think that even if you get yours wired so that it shows everything on everything you too will end up using the ARNAV and Sandel data far more than you will the 430 display.
Jerry Seckler

Here is the answer I received from Cirrus. I confirmed with Sandel that their present software does not support GPS #2 feeding Bearing Pointer #2 but that a future update will allow that. Cirrus in effect says that the wiring is there.
Cirrus: "GPS2 is wired to the Sandel on all of our Sandel installations, SR22 orSR20.

We had intended to display GPS2 as a bearing pointer, but the software is not done yet.
When the new software is done, it can be loaded into the Sandel, and the bearing pointer enabled to display GPS2 as a bearing pointer. By the way, the SR22 Wiring Manual does show GPS2 wired to the Sandel. "

Derek: I am not saying that. The problem of dealing with this issue as a warranty repair is that your aircraft was built in accordance with the aircraft wiring diagram that was prepared by Cirrus.

I understand that Cirrus has not distributed this diagram to any owners. It has a sort of “quasi secret” character because of that.

The real problem is that apparently per this thread and prior discussions regarding the Stormscope that these data connections are not in the Cirrus aircraft wiring diagram.

Since the connections are not in the Cirrus wiring diagram and since, apparently, Cirrus has not, so far as I know, proposed any changes in this diagram to accommodate these issues, your plane is in no sense “in need of repair”.

On the question of “Is this a good COPA issue to tackle”, I say, absolutely! Cirrus is not following the published installation drawings prepared and published by Sandel as regards both the RMI pointers and the Stormscope displays.

Both Sandel and Garmin have spent considerable engineering, manufacturing and marketing efforts to see that their products are capable of displaying information necessary or convenient to the safety of flight. We are paying for these engineering, manufacturing and marketing efforts by the purchase of these items of avionics.

Cirrus is not delivering a fully functional aircraft where data displays intended by Sandel and Garmin to be operational are not connected.

BTW, my understanding of a discussion between COPA and Cirrus with regard to the lack of Stormscope displays on the Garmin 430’s was that Cirrus made a “marketing” decision in not enabling Stormscope display on the GNS 430. What a crock!

In answer to your other question, yes you can have the #2 GPS connected to the Sandel. All one needs to do is look at Sandel document number 91006-10 sheet 8 of 28 Sandel Installation Manual Revision G(2) and follow it. Why Cirrus can’t do this is beyond me. Guess the bottom line is if you want it to work, you are just going to have to spend some more money on your 300K machine to make it work the way it was supposed to. While you are at it, you might as well have them hook up the Stormscope data at the same time.

Jerry, I agree with your usage of the various instruments. In fact, I too don’t look at the Garmins much. However, I do want the Stormscope shown there primary because it’s a great backup. The first thing I’m going to shed in an electrical emergency is the Arnav. This would also mean that I’m probably in the clouds with weather and will probably use the basic HSI of the Sandel because I won’t like the cluttered look. Having the weather on the Garmin #1 would be a great backup.

I try to create solutions to problems where I know I’ll be greatly stressed. These are the times that I need the ability to ascertain information. Putting the weather on the Garmin would indeed accomplish that with a failure of Alt 1.


James: Can you find out what the Wiring Manual shows regarding the RS232 connections between the Wx500 and the #1 and #2 GNS 430’s? Has Cirrus followed the diagram published by Sandel?

I certainly can’t argue with the benefit of backups. I do however have a question (it really is a question since I don’t offhand know the answer). Since there is no “on/off” switch for the Stormscope, and since the Stormscope controls are on the ARNAV, does killing the ARNAV by pulling the breaker also kill the Stormscope? I know there is a separate breaker for the Stormscope so you can “kill” the Stormscope without shutting down the ARNAV, but I simply don’t know if it works the other way.
If if does so much for your backup. If not it may make sense to have the display available on GPS1 although if you haven’t yet configured your Sandel and observed the Stormscope display on that you really should. I still think it’s a better picture than you’re going to get on the 430s, but I understand that is solely a matter of opinion.
My plan for any electrical problem in IMC is to get vectors to the nearest suitable airport and get on the ground ASAP.
Jerry Seckler N1970

Good question. I don’t know either. It seems that both the Sandel and the Arnav have “controls” for the Stormscope. In fact, you can have one in Cell Mode and the other in Strike mode. I don’t know how that would work however. The logic has to come from the Stormscope and I didn’t think it could be in both at the same time. That brings up another question… is it even connected correctly?

I’m embarrassed to admit that I never tried to control the Stormscope with controls on the Sandel. I didn’t even know it was possible. In fact, I’m not sure how one could get one display to show Cells and the other Strikes since the operating logic is in the WX500 not in the displays.
I would like to try some things out and experiment with pulling some breakers but, unfortunately, the thunderstorm season is about over and if there are no storms to display you just can’t tell what shows where and whether shutting down the ARNAV will also shut down the Sandel display of the Stormscope data. The darned storms are never around when you need them.
The question of “correct wiring” is interesting because there probably isn’t just one “correct” way to do it. I think there are multiple options in order to allow the WX500 to interface with many different units. Therefore the “correct” wiring would depend on how one wants it to display.
In any event we really need more information and I think this is a perfect job for Mike Radomsky at COPA response. I’ll contact him.
Jerry Seckler

Jerold: I talked to Tom Rogers at Avionics West last weekend about this specific question. He has had experience with a dual Garmin GNS 430 and single Sandel SN 3308 and Goodrich WX500 installation. He connects the output from the WX500 to display on the Sandel SN 3308 and both of the GNS 430’s exactly as the wiring diagram from Sandel shows. He also indicates that there is no difficulty in making even more connections than those three from the WX 500 RS232 output, as there almost no current drawn by the devices connected to the output of the WX 500.

As far as a “correct way” to make the connections, one can refer to the Installation Manual which Sandel has posted to their web site in .pdf format, particularly the diagrams at the end of the Manual. There is one diagram that shows exactaly the connections in a system having the Goodrich WX 500, the Sandel SN 3308 and two of the GNS 430’s. This diagram shows that the output from the WX 500 is connected, in parallel, to all of the three display units.

I don’t think that the “correct” wiring depends on how one wants it to display. As to all the devices capable of displaying the Stormscope data, each of them will show or not show that data depending on the pilot’s decision. The “correct” wiring is that wiring that will allow display of Stormscope data on whatever device is capable of displaying Stormscope data.

There is in fact a “correct” way to wire the aircraft, at least according to Sandel. Sandel has taken the time to prepare the drawings showing various combinations of other avionics with their SN 3308. The drawing that most closely matches the SR22 is found on sheet 8 of 28 of Appendix F of the Sandel SN 3308 Installation Manual Revision G(2). This is the way that Sandel intends the connections to be made.

Cirrus should not build two models of the SR22, one with the GNS 430 Stormscope RS232 input connected and one not connected, depending on the choice of the customer. The pilot may choose to display or not display Stormscope data.

The only difference between that diagram and the SR22 as delivered is the addition of the ARNAV display. Since Tom Rogers indicates that there is no reason that multiple displays can be driven from the RS 232 output of the Stormscope, the 3 displays shown by Sandel on it’s diagram can be made to be 4 displays on the SR22.

Also, the post regarding the “control” issue is correct. One can have the Sandel on “strike” mode and the Arnav on “cell” mode. I spoke with Goodrich at the time of the last AOPA convention in Long Beach. Goodrich says that none of the display units “control” the WX 500. The only “control” that is done is in each individual display unit. Choice of “cell/strike” or range, or clearing of the Stormscope data is all done internally on whatever display is showing the Stormscope data.

For some reason, the discussion of simply distributing the WX 500 Stormscope data to all of the display units capable of displaying that data, including the GNS 430 seems to get sidetracked into a discussion of which unit does a better job in displaying the data. That is clearly the pilot’s choice. If you don’t want to look at Stormscope data on the GNS 430 map or Stormscope pages, don’t turn it on. All we are talking about is maybe 2’ of wire.

So far as redundancy is concerned, I don’t have the answer to that. Since there is no current drawn off of the RS232 bus, it would seem to me that if any one or combination of the units capable of displaying Stormscope data were not operating that those would not affect the others. I’ll leave that question to those that know. However, I do recall a post some while ago to the effect that someone was flying while the ARNAV display went out and was thankful that he could still see the Sormscope data on his Sandel SN 3308. That would seem to indicate that the inoperative ARNAV did not in any way interrupt the data coming from the WX 500 to the Sandel SN 3308.

That would also indicate that in order to provide as much redundancy as possible that the Stormscope data should also display on the GNS 430’s.

As far as I can determine the only downside to making the connections to the GNS 430’s (both #1 and #2) is that the useful load is reduced by maybe a few ounces for the short length of avionics wire required to make the connection. The benefit to the pilot is not only operational flexibility - maybe the pilot prefers Stormscope display on the GNS 430 for some quirky reason - but additional redundancy should one of the units fail in conditions where Stormscope data would be helpful.

According to page 3-28 of the SR22 POH, the HSI and com 1 and nav 1 are all on the essential bus. I don’t know where the WX 500 supply is wired. If it’s supply is wired to the Essential Bus, then you have the Stormscope data on the #1 GPS as well as the Sandel. Depending on how you have set up the Sandel SN 3308 you may or may not have Stormscope data there. You may or may not have the Sandel on a range setting that is large enough to show weather other than in your immediate vicinity. If you had the Stormscope display enabled on the #1 GNS 430 nav 2 page (the map page) you would at least have that data available in the event of failure of the #1 alternator.

Thanks much for a logical and coherent answer to the many questions raised in this thread.
While I confess that for me having the Stormscope display on the ARNAV and Sandel is sufficient I would never argue that it shouldn’t be available on the Garmins as well. Too much redundancy is far preferable to to little.
In fact if all your info is correct I may have the wiring change made when I install my engine monitoring equipment.
Thanks again.
Jerry Seckler