Traffic avoidance and the ARNAV

Question for all you avionics buffs. Is or will traffic avoidance data be available on the big screen or are we restricted to the Garmins? If it is going to be available in the future is it a software upgrade or is there a major ($) hardware/re-wiring bill in my future? We are trying to decide if we should put BFG system in the plane now or later when the technology is available for the big screen. Thanks

I spoke with the main programmer who works on the ICDS-2000 yesterday. She said that their plans are to do a software version to match new hardware that Cirrus is requesting. Then they will add weather information uplink early in 2002, which is a business that Arnav is already in. She didn’t mention TCAS/TCAD. I believe that Arnav has written the software to interface to the Ryan TCAD. But the interesting version of that product, the 9900BX, with active interrogation, was not STC’d last I heard. Arnav was waiting for the STC’d version before they’d go through the effort to certify the software upgrade to interface to TCAD.

Anyway, this is all theoretical, because no one is going to install any TCAS/TCAD in a Cirrus aircraft without Cirrus’s blessing. This is because these systems require external antennas. External antennas require holes to be cut in the airframe. Holes in the composite airframe require structural analysis that only Cirrus has successfully done on Cirrus aircraft. At least, so far.

Cirrus has blessed the BF Goodrich Skywatch system. They did this because it was the only system with an STC. At least, this is my understanding.

I heard from Cirrus that the retrofit kit for the BFG Traffic Watch is still “in progress” and may be ready in the next month or two. But Cirrus is not good at predicting these things, so I don’t think anyone really knows when the kits will be available.

Btw, I’ve used the BFG system and I like it, except for the harsh male voice. I prefer the female voice in the Monroy Traffice Detector, which, unfortunately, I find almost useless.

Don’t mean to discourage anyone who might support the avionics industry by spending $20,000.

However, it is worth noting that, if you are “destined” to have an accident this year, the chances are 99 out of 100 that Skywatch or TPAS won’t save your bacon.


Because mid-air collisions account for only 1% of GA FAA-reportable accidents. And, 80% of those mid-airs occur in the pattern.

Thus, as Aviation Consumer has recommended, TPAS is probably a low priority for most pilots.

Recurrent training, an instrument rating, engine monitors, digital fuel flow, storm avoidance all rank higher.

Just something to think about before you plunk down $20k.

I believe that Arnav has written the software to interface to the Ryan TCAD. But the interesting version of that product, the 9900BX, with active interrogation, was not STC’d last I heard. Arnav was waiting for the STC’d version before they’d go through the effort to certify the software upgrade to interface to TCAD.


Just FYI, the Ryan 9900BX just got TSO approval within the last couple weeks. I talked with one of the Ryan guys just last week, and they confirmed it. I think it’s STC’d in one particular airframe (something like a Cessna 414 I think), and they’re not planning to do STCs for any other aircraft. In the past, with most metal airframes, people have been able to install the ryan system via 337, just refering to the STC that Ryan had.

As you point out, this isn’t the case with the Cirrus.


My SR22 (N747SJ) was delivered last month with with the Skywatch system installed by Cirrus. The top antenna is large - looks like a flat external GPS antenna - but it’s four times the size. The system works great and is interfaced to both 430’s. I’ve flown nearly 40 hours in the past month and typically leave 430 #2 on the Nav page showing either 2 or 6 mile traffic. With all the maps, it’s not really necessary to have this on the Arnav - though it would be nice to use the panel as a real MFD.

When a target is at an altitude and heading that the system considers a threat (within two miles), BOTH 430s immediately flip to the TCAS display and the audible warning of ‘Traffic, Traffic’ comes on. I’ve already had two close encounters that the system caught.

Chris N747SJ

Chris: It’s great to see a pirep on the Skywatch. I gather that you generally leave the 430 #2 on the nav 3 page.

When you got the 2 Traffic Advisory did you see the traffic immediately? Did you have to manuver to avoid that traffic? Was this in the pattern, on approach, or enroute?

I gather the system has been problem free since you don’t mention any problems.



BOTH 430s immediately flip to the TCAS display

Can the Garmins be set up so that just one of them does the automatic switch to the traffic page?

Also, does the alerter become annoying in the traffic pattern and/or do you disable it when entering the pattern? I believe that I saw a note that it automatically goes to standby when it detects that you are on an approach, but it seems like it has the potential to become a distraction when entering the pattern VFR.

It has been completely trouble free. I don’t claim to be an expert on all the functions but it has popped on a couple of times in the pattern. Not really a problem but a bit distracting. Moving it to standby mode is an option (this does not happen automatically except after landing - the Skywatch goes off line automatically just like the GTX327)

The two events that I had were both enroute. I now fly a good deal of GPS direct. The system simply pops up showing the position of the target and it’s altitude above or below. In both events, I had the traffic in seconds and did not need to change course. I also did not have flight following on the flights.

I fly in the San Francisco area and consider the Skywatch to be worth every dime…


Gordon: As far as I can tell from the POH supplement to the Garmin, all that you need to do with one of the GNS 430 is to select “standby” on that GNS 430. With the other unit in :operate" you should only get the alert on one unit.

As far as alerts in the pattern are concerned, it is a little more complicated. I believe the way that
Cirrus configures the Skywatch is that it takes a ground speed in excess of 30 kts. from the GNS 430 and then switches from “standby” to “operate”. There are two alternative methods to do this, neither of which apply to the SR22. First is a squat swich, which would have much the same functionality as the ground speed exceeding 30 kts. The second is a radar altimeter which outputs data in the format required by the Skywatch. I think the Skywatch can be set to automatically set the “protected zone” based on a radar altimeter altitude in excess of 2500’ setting the “enroute” larger zone and less than 2500’ setting the smaller “pattern” zone.

Take a look at the “Weather Traffic Supplement” on the Garmin web site for more detail. Switching from “operate” to “standby” is only 3 steps: cursor, small knob and enter. As far as I can tell, the manual does not describe setting the range when you are in the traffic page. I would guess it is done by the menu key and then the small right knob then enter. It shouldn’t be hard to change the range setting appropriate the traffic pattern, particularly if it’s on your approach checklist and done some time before the approach.


Thanks for the info. I do have the Garmin traffic & weather “Pilot’s guide addendum.” But it is unclear whether setting the SKY497 to “standby” on the Garmin sets the SKY497 itself to standby mode (thus disabling it on the other 430) or just affects the local display. Page 12 of the addendum states:

“When in standby, the SKY497 does not transmit, interrogate, or track intruder aircraft.”

This would seem to indicate that the standby mode is global, not local to a 430.

Maybe Chris can shed some light on this for us.

I don’t have Skywatch or any traffic avoidance. If is true that only 1% of the accidents are mid airs, who’s to say that they WOULDN’T have been prevented by having Skywatch? Also remember, that even though the chances are slim, if it is you that is involved your chances are 100%.

I’m taking a risk by not having Skywatch. But I’ve accepted that risk. I was flying yesterday at a nearby non towered airport practicing landings. A King Air was on final while I was on downwind and I didn’t see him! How could I miss a King Air? Never did see him, but luckily we all were talking on the radio.

I love statistics, but I don’t think there is one out there that says your chances of having a mid air collision while having Traffic Avoidance is xx% enroute and xx% in the pattern and even then unless you know the methodology it’s difficult to ascertain what those numbers really mean.

Example, it has been said that flying general aviation is more dangerous than driving. For whom? Taking those same statistics used to generate those numbers, I concluded that I was AS SAFE flying my 172 as a a passenger on an airline jet. How? Well, as a pilot of a 172 with over 500 hours in type, my chances for a fatal accident were on par with a Part 121 carrier based on the Air Safety Foundation statistics.

Just another thought.


Derek -

Just to clarify the statistics, the point was that IF YOU WERE DESTINED TO HAVE ANY ACCIDENT IN THE NEXT 12MONTHS, (and, implicitly your distribution of accidents matched the recent Nall report on all GA accidents), the type of accident you’d have would only be a mid-air in 1 case out of 100. Or put another way, if you equipped all 1700 planes that had accidents last year with a TCAS, you’d only eliminate 1% of the accidents - the other 1683 were not midairs.

So, unless a TPAS/TCAS can prevent something other than midairs, it can only prevent 1% of the accidents out there. The point is, if you’ve got limited funds, there is more leverage going after the other 99% of the accidents. Training, instrument rating, fuel monitoring, engine moritoring etc.

If you’ve got unlimited funds and have already covered all the other bases Aviation Consumer recommended, then go for it.

Statements about statistics are slippery things.

If I were destined to have an accident in the next 12 months, the chances of it being a mid air are a lot more than 1%. The reason is that I (like most or all of you) have greatly reduced the chances of some other accident types. E.g., I think about 20-30% of accidents (this is from memory) areof the low-level maneuvering kind. I don’t buzz people or things, or get close the ground except when taking off and landing, so the chance of this happening to me are less than the average. Ditto for flying into IMC without being instrument rated, as I am instrument rated. While I might still have a VFR->IMC accident, the chances of this are less than for the average pilot (the average pilot doesn’t have an instrument rating). I cannot suffer a vacuum failure in the 22. The likelihood that I’ll run out of gas is very low, given accurate gauges, a low-fuel light, a very accurate fuel totalizer and a fuel-to-destination calculation always in front of me.

I’m not saying that I’m a super safe pilot or that the '22 is a super safe plane, just that the probability distribution for a particular pilot in a particular plane can be quite different from the distribution for the average pilot.

Said another way, we’ve already eliminated or reduced a number of accident types, so the remaining types have an increased probability, if we are destined to have an accident.

Also, there are things we purchase, like new paint or chrome spinners that have little safety value. Sometimes we purchase things for peace of mind. For me, getting Skywatch is partly a matter of improving my odds a little, and improving my peace of mind and that of my pax a lot.