New Arnav software - brief news item

I took my first flight today with the new Arnav software. Details in the next day or two, but headline version: THUMBS UP! Display is dramatically better, Arnav has actually thought about some of the limitations of their previous version.

A few small glitches. (Only significant one: It IS slow, as others have pointed out.) But on the whole a very worthwhile investment.

Speaking of worthwhile: Stormscope really is worth its weight in some valuable commodity. Was coming from New Haven to the DC area, knowing that a big belt of thunderstorms was approx 100 miles to the west. Stormscope a very, very useful tool for making sure they were still far enough away.

Here is some extra info about the Arnav “H” release. My two bottom-line points are that it’s a big step forward, and that for existing Arnav owners, the $2k price for this upgrade is, in my judgment, a better value than paying five or six times that much to switch to Avidyne.

  • Resolution vastly different. I was flying along the Atlantic coast yesterday, and it was surprisingly valuable to have a realistic-looking modeling of rivers, ocean, inland hills, and so on.;

  • Declutter options work well for different circumstances;

  • Some other Arnav upgraders have said that changes in the control system were confusing. I’m not sure I would have noticed that the controls were different at all. They’re tied to on-screen icons and I was able to use the system without ever looking at the manual.

  • Display is bright, even in direct sun;

  • Integration with Stormscope was good – and in some vague way seemed more informative at-a-glance, because the improved display gave a more realistic sense of situational awareness; NOTE IMPORTANT CAVEAT BELOW.

  • Surprisingly valuable feature: the “terrain box” ahead of the plane. As shown in Del’s Alaska report and the Arnav web site, there is a little rectangle that extends in front of hte airplane, to show where your current path will take you. One intended purpose is to indicate terrain clearance. I was flying over the East Coast flatlands, so that didn’t matter. What DID help was this box’s indication of where my current heading would take me, in terms of restricted zones, Class B airspace, etc. I was hand-flying my way down the coast rather than on a point-to-point Garmin plan, and having this guidance to let me know whether I was going to hit various airspace was handy.

  • Did I mention that the resolution was better?

    • SLOOOOOOOWWWW. Switching from one resolution to another – zooming in and out – can take 20 seconds or more. As Don Rennie, I believe, pointed out, you can click the zoom button several times and then let it refresh, so you don’t have to do sequential cycles of 20 seconds for each zoom level. This is very much different from old Arnav and indicates the system’s older-tech heritage than Avidyne. STILL, once you understand this point, it leads to more “strategic” use of the screen, and less tactical fiddling with it. I didn’t mind that much.
  • This may reflect the fact that I didn’t yet read the manual, but so far I can’t figure out how to do one of my previous favorite Arnav tricks. This is the “runway alignment” trick: If you’re heading for Runway 32, you set the HSI to 320, hit OBS on the Garmin, and then you see a big magenta line on the Arnav showing the extended centerline of the runway you’re heading for. That trick still works for the Garmin itself, but it doesn’t seem to transfer to the Arnav in the way it did before. (For some airports, you can approximate the effect by choosing an ILS approach for the runway in question and activating “vectors to final,” which gives you the controllers-eye view.)

  • Agree with Don Rennie that the point-obstacle display (tower elevations etc) is clumsier and more obtrusive than before.
    On balance
    – If I were buying new, I would get the Avidyne, because I just have more faith in the company’s technical future;

    – As an Arnav “legacy” owner, I am happy to have gotten this upgrade, which is a big improvement and by GA standards quite a bargain;

    – We’ll leave for another time the relative value of other Arnav add ons, the engine monitoring and the Stormscope. The Stormscope is twice as expensive as the engine system, but my experience to date (contrary to prevailing wisdom) is that the Stormscope is about 100 times as valuable. In part I say that because I’m now using the Stormscope in its ideal east-of-the-rockies location. (During the year I used a Cirrus in California, I don’t think I ever turned it on.) In part I say it because the oddities of my engine monitoring setup so far limit its value – I trust it for CHT/EGT but not for anything else, including RPM reading, power %, or remaining fuel. Presumably I can get those adjustments tweaked.

That’s it. If you have Arnav, my vote is to get the upgrade.

IMPORTANT STORMSCOPE CAVEAT. If you install the software upgrade yourself (after necessarily getting the ICDS hardware swapped at Arnav HQ), the procedure is easy and straightforward. HOWEVER, by default the installation-and-upgrade process turns OFF the Stormscope. As I mentioned yesterday, my first trip with the new software was the kind of day the Stormscope was meant for. A muggy East Coast day with a known band of thunderstorms far enough away to be safe but too close to ignore. When I was doing the runup, after installing the software myself, I found to my dismay that I no longer had a Stormscope. I vaguely remembered that Stormscope settings were part of the Arnav “Setup” screen, so I went through the drill (on the runup ramp) to configure the Stormscope to “On.” My point is, be aware that adding the new software initially switches the Stormscope “off.”


Some of the material I’ve read on sferics (the generic term for lightning detection systems) has suggested that they are very good at showing the direction of cells, but much less accurate on distance. (for example Mike Busch’s Flying Real World Weather on AvWeb). But it sounds like you were comfortable keeping the storms at bay with it.

I’m especially interested since I’m about to follow in your footsteps, leaving the Bay Area next month for a cross country flight followed by a month of flying up&down the Eastern seaboard. This will be a real adventure for this Left Coast pilot!


Arnav sent me instructions to take the ‘obstacle clutter’ down to the 15M zoom as before…I use 25 and 50 most often…If you or anyone would like the instuctions…just email me and i’ll forward them. It was very simple to complete.

Curt, thanks, good point. What I “meant” to say was that the Stormscope was very useful in getting the overall picture of the storm belt. I was headed SW more or less along the coast. When I started, the worst of the storms was in middle/eastern Pennsylvania. But it looked as if their general movement was NE – parallel and opposite to my course – rather than the dreaded straight East, which would have taken them across my path. For relative movement and intensity the Stormscope seemed very useful.

Also had an experience like one that Mike Busch explains in that very good “real world weather” article. Near Wilmington, Delaware, I saw off to my left what looked like an enormous, towering thunderhead. The base was about 5000 feet (I was creeping along at 2500, which believe it or not is a safe obstacle-clearing distance in much of the mid Atlantic.) There seemed to be a lot of rain pouring out the bottom of it. But there was not a blip on the Stormscope in that direction, in either Strike or Cell mode. Perhaps it was some Scope malfunction. Perhaps, as Busch suggests, the cloud was all water, no convection. One way or another, I gave it a wide berth.

Curt, It’s true that the distance info on the Stormscope is not as accurate as the azimuth, but the error is usually on the conservative side. That is the storms appear closer than they really are. Give the strikes a wide berth and you’ll do fine.
I wouldn’t fly in IMC without the Stormscope in thunderstorm country.
Also, as Jim pointed out not all rain shows electrical activity. My philosophy is that if the clouds look bad, avoid them. If there’s electrical activity even though the clouds in the area look innocuous, avoid the area. My experience is that if there’s no electrical activity there is not significant turbulence (key word significant)- you may get bumped around but it isn’t the sort of turbulence that makes you loose control of the plane or your natural functions. When there is electrical activity the air is always uncomfortable.

I don’t know why I never saw the real version of this, but there’s a valuable online PDF manual for the Goodrich Stormscope used with the Arnav, here:

Very clear and practical explanation of where it’s accurate and where it might not be. Also explains why “Cell” mode is much less subject to error than “Strike” mode

I had the same experience you described a few weeks ago flying from Nashville to Charlotte behind the frontal line that caused tornado watches to be issued from northern Alabama to central North Carolina. I was in pretty close proximity (within 2-10 miles) and observed numerous very well developed cumulonimbus formations producing no rain. I was not getting the returns on the Stormscope that matched the appearance of 30,000’ tall cumulonimbus clouds associated with tornado warnings and convective sigmets. I am no weather expert, but I spent 10 years flying gliders competitively, and I know what clouds associated with convection look like. I switched between cell and strike mode several times, and it did not seem to make much difference on that particular day.
Last week, I talked with our corporate pilot about his experiences with Stormscope (which the company plane has). He said that it was more useful when used in cojunction with radar (which the plane also has). I also asked if he felt radar or Stormscope was more useful for avoiding turbulence and he said he preferred the radar. I was very surprised to hear this, because Stormscope is supposed to be better for that. Besides, we just spent about $20,000 for those little 'X’s to be displayed on the screen.
All in all, I am not ready to say it was a waste, but I am a little more skeptical than I was before I had it. I want to use it in real IFR in the thunderstorm season here in the southeast some more before I develop an opinion.

Yes, thanks. Please post them if they are part of the setup.


In reply to:

I was in pretty close proximity (within 2-10 miles) and observed numerous very well developed cumulonimbus formations producing no rain. I was not getting the returns on the Stormscope…

Greg - By any chance were the storms off to the side of the aircraft rather than ahead or behind? I have been told that the Stormscope has “blind spots” (or at least attenuated spots) at 9 o’clock and 3 o’clock.

So should we be making S-turns for our Stormscopes?


They were only about 15-20 degrees off the nose when initially encountered and as I got closer, naturally, they passed by on the right side. I was looking for the ‘blind spot’ you mention because I had read a post about that before that flight. That did not seem to be the problem, but as I mentioned earlier, this is going to get more scrutiny in upcoming months.