ARNAV Weather - Remember Us??

Are the ARNAV owners, who still constitute the vast majority of the Cirrus consituancy, going to have the benefit of on-board weather?

-Is this a Cirrus or ARNAV issue?
-What is the outlook?
-Is the total absence of any communication from Cirrus on this indicitive that they don’t care about those who brung 'em to the party?

I would loved to have heard something like “While the development of on-board weather is ultimately dependent on ARNAV, we encourage them to do this, and we stand ready to devote the necessary resources on our end to help bring it to our users as soon as possible.”

The silence is deafening.


My understanding is that this IS an ARNAV issue. They WERE in development of a ground based broadcast system at least 3 or more years ago which has not “gotton off the ground” so to speak. Given the track record of ARNAV over the last year, I would not hold my breath waiting. Until ARNAv has a product, Cirrus cannot offer it. Most of the new deliveries are with Avidyne units which is what Cirrus is currently working with.

While not an optimal solution, Garmin will offer the GDL 49 WX satellite downlink soon. It will probably display off the Garmin 430 and not the Arnav. It will get datalink wx in the aircraft. Satellite datalink seems to offer the best coverage rather than ground-based which is altitude dependent.
Don Kusenberger

Brian, I don’t question your point that it is an ARNAV issue. As a matter of fact, someone else e-mailed me with a similar point.

I still feel that Cirrus ought to have a communication on this:
-It would be nice to know where the stress point is. Of course, they should do it in a factual, not accusatory way (like my very well-written suggestion on my original post).
-It would seem to be important that ARNAV know that if they put the resources into developing this, they won’t have a roadblock with Cirrus on getting the job completed.
-It puts some gentle pressure on ARNAV to do the work - prevents them from pointing fingers at Cirrus.

I know there’s been a divorce between Cirrus and ARNAV, but they had hundreds of children together and they both need to do their part to assure the kids don’t get caught in the middle.

With your comments, which I feel are valid, and two private e-mails, which I also feel had valid comments, I still can’t see a justification for Cirrus excluding ARNAV in either their public comments or their private discussions. Can’t speak to the private discussions; the lack of comments to us speak for themselves - so to speak.


I see your point. But from a practical standpoint, since Cirrus is not actually delivering any ARNAV equipped planes anymore, any future introduction of Datalink by ARNAV will have to marketed as a retrofit to all current ARNAV owners which really does leave Cirrus out of the whole discussion.
But, you are coreect, that Cirrus started the “marriage” with ARNAV and included in their original brochures the notion that datalink would be availablr for ARNAV. This may be one of those issues where it just does not make sense for Cirrus to push ARNAVto do anything when they do not have a relationship with them anymore.
But I STILL say the real problem was lack of production of the system on the part of ARNAV in the first place. I went to a seminar in 1999 when ARNAV reps spoke of the notion that datalink was just “around the corner” for them. This seminar was totally independent of Cirrus at the time. What happened to it since then?

Brian, you bring up a point about which I profess no knowledge. Does Cirrus have to be involved in getting weather approved fro their planes? I always thought they did, because of things like antennas, wiring, etc. For example, it seems like they were involved in Skywatch retrofits.

Brian or anyone else - what’s the scoop on this?


I know of no requirements that the aircraft manufacturer or Type Certificate holder get involved in any STCs or field approvals. At this point, that is all that should be required.


Is a new antenna required?

A new antenna will be required for ANY datalink setup whether it be for ARNAV or Avidyne. Cirrus will likely offer factory installs for the upcoming datalink for new customers with the Avidyne. Since ARNAV does not have a system, and Cirrus is no longer selling ARNAV products, Cirrus will likely not be involves in any future ARNAV datalink system, if one ever become available.


As Brian mentions in his reply, a new antenna would almost certainly be required. But Cirrus really doesn’t have to get involved – although it would sure be NICE if they and Arnav worked hand-in-hand to develop a kit for installation of an Arnav datalink, it doesn’t have to happen that way. Arnav could just hire a DER and do a little engineering work on their own in order to get an STC. I would daresay that would be trivial compared to the task of setting up a few hundred datalink towers, if that’s what they intend to do.

Keep in mind that even to this day, Cirrus has never offered the Arnav engine monitor nor ever come out with a kit or SB for its installation. That was all completely done by Arnav. So I think we’d see a similar thing if/when Arnav ever comes out with a datalink.


Remember folks that your GPS antennas are mounted under the glare shield and under the headliner. With a fiberglass airframe, there is no reason why the datalink satellite antenna can’t be mounted above the headliner. This would certainly make the STC easier to deal with!


Avidyne uses a receiver called the DX50 to process the satellite data. The antenna indicated for the DX50, at least in their pictures, is an externally mounted antenna. Another question to put on Gordon’s list for Avidyne: Can the antenna be mounted internally?

I thought the same thing and wondered why it could not be done. I asked all the weather vendors the same question, why not an internal antenna? Some thought the carbon lightning protection would interfere, some just had not thought about it. But none of the vendors at OSH were very excited about this approach.

Arnav said no, needs an antenna outside and that they were not working with Cirrus on it (I read that as very unlikely to get weather on my Arnav - ever much less soon).

Avidyne is using a coupler (mentioned in another post to avoid the new antenna). Shown on a price list as a DC50 “Antenna Datalink Coupler”. Cost is 495.00. Think it is not ready until November. I would rather do that myself.

WSI said they might test it if someone would work with them, but that they did not feel overly excited that it would work. They are not working with Arnav, but are working with Avidyne.

Garmin said, needs an antenna.

As you can tell, I was specifically looking at weather products.

Frankly the best currently available product is AnywhereMap. It is portable and does not require an STC, but I do not want all the wires and electroncs loose in the plane (like a PDA, a GPS, a box they provide and a Sat Cell phone. Its a wiring nightmare…

Ah, the pleasure of being an early adopter…


In reply to:

. Another question to put on Gordon’s list for Avidyne: Can the antenna be mounted internally?

I’ll certainly ask.

I spoke with Avidyne at Osh about the system. The initial release requires its own antenna. However, they are working with Cirrus to multiplex access to an existing antenna.

The plan is to switch the COM1 & COM2 antenna’s so that COM2 is the one on top of the plane. The Avidyne weather system can then use the COM2 antenna so long as COM2 is not transmitting. The Avidyne would go offline during COM2 transmissions. Retransmissisions in the data protocol would make the multiplexing transparent to the pilot.

As in all things, Avidyne said availability would depend on Cirrus.



I have the Compaq iPAQ with AnywhereMap. The software itself is great, but as AnywhereMap warns you, be careful of the flimsy connector on the iPAQ used to interface to the GPS. While waiting for N224AZ I rented an ARCHER (yuk), and used the AnywhereMap to get around. (What’s a VOR?).
The connector did get damaged from the GPS, but fortunatily the “new” HP fixed it free.




Thats exactly why I want it on my MFD. Thanks.



I also have the Anywhere map with wx. Controlvision makes a part that attaches to the Ipaq plug that keeps it from being damaged.


Thanks for the input Paul. I checked out the sleeve lock and wish they had it a year ago.

Take care,