ADS-B: Am I missing something?

[sba55]

With the FAA re-opening the ADS-B comment period, I looked over some of the ideas behind this proposal. Some of them really have me worried:

- No more flight following. If that's true, it sounds like it would be really detrimental to safety. FF is about much more than just traffic advisories - staying in touch with ATC in case there's a problem, staying up to date on what's going on in the area, coordinating traffic and airspace clearances, etc. ADS-B, especially the "out" kind, doesn't offer any of these. Are we losing an essential service?
- Aircraft visibility. Unless I'm misinterpreting the proposal, ADS-B wouldn't be required outside Class A/B/C below 10,000' MSL. If they're also eliminating Radar, how are they going to advice IFR planes of other traffic? For that matter, that traffic wouldn't show up on your ADS-B display either. Isn't that a really big problem?
- And related: What if there's an electrical issue? Does your plane disappear from their system (no primary returns anymore, either)?

What am I missing? I hope it's something important.....

-Felix

 

[SCCutler]

Felix, anticipate new requirements and restrictions which would essentially do away with all but the most basic of GA flying, or force it upstream in the expenses. Look to Europe for the model.

 

[silver-eagle]

I wonder if maybe their initial approach would be ADS-B equipped aircraft won't receive flight following since you're picking up traffic and weather already. Of course, hey probably thought the same thing about TIS.
I think companies do more for monetary reasons than safety. The FAA is no different. Even if we had user fees, we'd still see them headed that way.

 

[TMetzinger]

The idea is to eliminate the radar infrastructure, not so much to eliminate controllers, as I understand it. If we're all equipped for ADS-B out, then they can eliminate a lot of radar hardware and data network lines. With ADS-B in, we'll get automagic traffic info for planes in our vicinity, even if all the ground equipment is dead - that's a step forward from TIS and gives us the equivalent of TCAS at a lower cost.

I expect all sorts of political and technical wrangling over mandatory participation, weather upload (look for current satellite weather providers to push against being put out of the business), and integration with avionics.

 

[gprellwitz]

The idea is to eliminate the radar infrastructure, not so much to eliminate controllers, as I understand it. If we're all equipped for ADS-B out, then they can eliminate a lot of radar hardware and data network lines. With ADS-B in, we'll get automagic traffic info for planes in our vicinity, even if all the ground equipment is dead - that's a step forward from TIS and gives us the equivalent of TCAS at a lower cost.

I expect all sorts of political and technical wrangling over mandatory participation, weather upload (look for current satellite weather providers to push against being put out of the business), and integration with avionics.

Well, we'll get automagic traffic info for planes in our vicinity who have functioning ADS-B equipment. If they're experiencing an equipment failure, they won't show up. Plus, I'm sure the DoD and Homeland Security are going to maintain the infrastructure for RADAR anyway, so it's just the cost to get the information from the RADAR sites to ATC that'll be saved.

 

[sba55]

With ADS-B in, we'll get automagic traffic info for planes in our vicinity, even if all the ground equipment is dead - that's a step forward from TIS and gives us the equivalent of TCAS at a lower cost.

I don't think that's true. As far as I understand the proposal, ADS-B will only be mandatory in certain kinds of airspace and above 10,000'. Since there's a lot of people who don't fly in those areas, they won't need ADS-B, and they won't show up on your ADS-B equipment or on the controller's scope.

I find that to be really, really scary. We won't know about a lot of planes out there anymore unless we're lucky enough to spot them visually.

Also, while it's true that we'll get automatic traffic advisories on _some_ planes, the elimination of flight following is a huge deal, isn't it? It seems to me that flight following is about more than just traffic advisories.

Personally, this move seems like a huge mistake. Without even debating if we as GA get ny benefit from this (I'd say we don't, since a 496 provides weather for a much lower cost and FF ATC can give us traffic advisories on every plane, not just ADS-B equipped ones), it seems like we're losing a lot of VFR services. Is it the end of VFR?

Spike, I hope you're wrong....

-Felix

 

[flyersfan31]

They've really backed away from the ADS-B In feature, too. It's all about the out, not too much about in. So, we pay $$$$$ to save them money, and get nothing in return. Look for AOPA to lean very hard on them to retain the traffic and wx bennies that they sold us on upfront. What a frickin ripoff otherwise.

 

[Walt]

The GA pilots are legitimately wondering what they will be getting for the considerable cost of equipping their airplanes with ADS-B.

Several years ago a retired FAA guy told me that the primary reason ADS-B was implemented was that the increased accuracy would reduce separation standards to three miles (everywhere) and would allow higher flow rates into nonradar airports. It would also increase safety and in some places lower approach minimums. Originally, the designers thought that radar coverage could be reduced (saving lots of tax dollars). Unfortunately the DOD and TSA would not go along. Now that the system is partially implemented it looks like we are stuck no matter what the cost. I think the FAA and airlines see the lower separation standards as worth the cost and will continue implementation.

The same FAA guy said that a study indicates that 87% of the traffic in the US uses Class A,B,or C airspace or the airspace over/under the class B or C on a regular basis. Based on this it appears that many airplanes will have to be ADS-B equipped.

Years ago the pilots fought off the proposed requirement to install Mode S. Mode S would not have lowered the separation standards, ADS-B will. ADS-B will therefore increase airspace (system) capacity reducing some delay. For that reason, it will be exceedingly difficult to get rules different from those proposed. I am not optimistic that GA will be able to stop or modify ADS-B.

 

[sba55]

Walt, you share some interesting insight in your post.

What really bothers me is this idea that it's ok for some planes to be invisible to ATC and to us pilots. On almost every flight, I'm advised of traffic. Without radar, there's no guarantee that ATC would even have seen that traffic.

Also, relying on airplanes to accurately broadcast their position and not having any redundancy in case that equipment fails strikes me as very dangerous. I really doubt that 87% of traffic regularly operates in A/B/C....

Finally, airspace congestion seems like a small problem compared to airport congestion. The airlines and their scheduling practices are responsible for the latter, and ADS-B won't solve the issue.

-Felix

 

[SCCutler]

Walt, you share some interesting insight in your post.

What really bothers me is this idea that it's ok for some planes to be invisible to ATC and to us pilots. On almost every flight, I'm advised of traffic. Without radar, there's no guarantee that ATC would even have seen that traffic.

Also, relying on airplanes to accurately broadcast their position and not having any redundancy in case that equipment fails strikes me as very dangerous. I really doubt that 87% of traffic regularly operates in A/B/C....

I believe it- I am confident that they are not talking about 87% of airplanes; but rather, 87% of total airplane miles.

Finally, airspace congestion seems like a small problem compared to airport congestion. The airlines and their scheduling practices are responsible for the latter, and ADS-B won't solve the issue.

-Felix

Common sense- too bad it's not so common! They need some Agile Engineer to show them how things *really* work.

 

[sba55]

I believe it- I am confident that they are not talking about 87% of airplanes; but rather, 87% of total airplane miles.

That I do believe, too...

Common sense- too bad it's not so common! They need some Agile Engineer to show them how things *really* work.

I'm not aware that the FAA has hired consultants, but if they do, I'll volunteer for that project....

 

[Ted]

I believe it- I am confident that they are not talking about 87% of airplanes; but rather, 87% of total airplane miles.

You got it. That 87% of traffic, be it total airplane miles, number of airplane flights, etc., is going to be your commercial jets that are using A, B, and C airspace. I definitely believe that number. In GA, we have something similar. 80% of the 100LL out there is burned by 20% of the planes. Don't believe it? A Cherokee burns what, 10 gph? A Navajo burns 40 gph, and that same Navajo probably flies at least twice as many hours. Yep, it makes sense.

I use flight following on every flight (unless I'm going IFR), and I consider it dumb not to, with few exceptions. I suppose part of my question is what will this mean for instrument flights? Will people like me flying the Mooney around under IFR now be restricted or unable to fly it? And if I want to fly above 10,000 MSL, do I now need to get ADS-B installed in? I'm not up on this at all.

 

[Walt]

sba55,
I have not decided how I feel about spending $15-20K on ADS-B equipment. At this point I do not see the necessity. It will be redundant since mode C will still be required. Since I fly around Class B all the time my mode C is always running. Most of the time the traffic I encounter (within 30 miles of Denver) has mode C running. When I am out of the Class B I find some people that do not use their transponders. Usually this is not a big problem except when I am IFR and they are scud running. I have had several close calls with aircraft not using or having nonworking transponders. ADS-B will not solve this problem.

The only gain I see for GA buying ADS-B is for weather information (not implemented as yet). It is truly a lot of dough for something that is already available on XM.

The FAA, of course, is looking at capacity and automation. How this system will help them is anyone's guess at this time. With the price of gas in the clouds right now traffic is decreasing so the 2020 target for ADS-B may move back. I think it will become a requirement in the not too distant future.

BTW, I do not think the 87% was all that accurate a number but I couldn't give a better number. Air traffic is concentrated around population centers.

 

[sba55]

You got it. That 87% of traffic, be it total airplane miles, number of airplane flights, etc., is going to be your commercial jets that are using A, B, and C airspace. I definitely believe that number. In GA, we have something similar. 80% of the 100LL out there is burned by 20% of the planes. Don't believe it? A Cherokee burns what, 10 gph? A Navajo burns 40 gph, and that same Navajo probably flies at least twice as many hours. Yep, it makes sense.

That's not correct. GA flies as many, if not more, hours than schedules operators, and we have a lot more departures. I don't know how many of those hours are flown in controlled airspace, but I'd guess that it's not very many since most GA airplanes don't fly in A airspace....

I use flight following on every flight (unless I'm going IFR), and I consider it dumb not to, with few exceptions. I suppose part of my question is what will this mean for instrument flights? Will people like me flying the Mooney around under IFR now be restricted or unable to fly it? And if I want to fly above 10,000 MSL, do I now need to get ADS-B installed in? I'm not up on this at all.

First, your VFR flight following will go away if this proposal is implemented.

Second, you'll have to get ADS-B if you want to fly above 10,000' and probably also if you want to fly IFR without too much hassle (maybe they'll allow position reports, but who knows....)

 

[Bob Noel]

something else to consider: How are ADS-B transmission authenticated or validated?

Misuse of the answer is left as an exercise for the student....

 

[flyersfan31]

Read this for a very interesting critique of ADS-B. He raises some scary concerns.

http://www.airsport-corp.com/adsb2.htm

 

[Ted]

Read this for a very interesting critique of ADS-B. He raises some scary concerns.

http://www.airsport-corp.com/adsb2.htm

I think this guy raises paranoia to a new level. I wouldn't use these as concerns for why ADS-B shouldn't be implemented.

That said, I think my biggest issue is, what's wrong with how things are today?

 

[Bob Noel]

um, I think that guy saw Die Hard 2 a few too many times.

 

[Ted]

That's not correct. GA flies as many, if not more, hours than schedules operators, and we have a lot more departures. I don't know how many of those hours are flown in controlled airspace, but I'd guess that it's not very many since most GA airplanes don't fly in A airspace....

Interesting stats. It would look like they could be getting their numbers from number of passengers flown (those stats say GA is about 14%, which would correlate pretty well with the 87% using A, B, and C airspace). That's one thing I don't like about statistics - they'll say whatever you want them to.

First, your VFR flight following will go away if this proposal is implemented.

Second, you'll have to get ADS-B if you want to fly above 10,000' and probably also if you want to fly IFR without too much hassle (maybe they'll allow position reports, but who knows....)

Well, I can tell you if flight following goes away that'll give me more incentive to file and fly IFR, but I do not like the idea of spending another $15k on avionics when what's currently in there works just fine.

Seems like another waste of time and resources...

 

[Steve]

I downloaded this last year when I was trying to find info on whether a 430w would integrate with proposed ads-b requirements.

It's one of Boeing's responses to the NPRM. I pulled it off the docket list of responses.

 

[Walt]

Steve,
I looked with interest at Boeing's remarks. The phasing of ADS-B does not concern me as much as the equipment required. I was wondering if you have determined if a 430W will meet the proposed regulations and if you know whether GPS's meeting TSO 129 will qualify. The biggest cost of complying with this proposal will be buying and installing a new WAAS GPS. It will also take a new transponder. I understand the FAA has sent the avionics industry the proposed regulations including proposed maintenance regulations. This means everything is can change but I would appreciate the any information you have dug up.
Thanks

 

[jmaynard]

The last I saw, Garmin had a PowerPoint that said a 430W and modified GTX330 would qualify for ADS-B Out. I sure hope so, because all that would take is an upgrade to my GTX330.

 

[flyersfan31]

The last I saw, Garmin had a PowerPoint that said a 430W and modified GTX330 would qualify for ADS-B Out. I sure hope so, because all that would take is an upgrade to my GTX330.

YABBUT - so what? Without ADS-B In, the benefit to you is limited, at best, over current radar systems.

I love it, the FAA sells this great expensive system with the promise of wx and traffic, then silently drops it, leaving only the expense.

 

[jmaynard]

YABBUT - so what? Without ADS-B In, the benefit to you is limited, at best, over current radar systems.

I'm not arguing that...it's just that, when the FAA does mandate ADS-B Out, my expense shouldn't be too terrible.

That doesn't mean that I support the move. Mandating ADS-B Out and doing away with the current system is a terrible idea. However, I won't be terribly surprised if they do it anyway.

 

[Ted]

That doesn't mean that I support the move. Mandating ADS-B Out and doing away with the current system is a terrible idea. However, I won't be terribly surprised if they do it anyway.

I know my flying club will throw a fit when this happens - people who don't even want to put an IFR GPS in the plane. They'll probably just choose not to and increase the restrictions upon people who want to fly the planes.

So this poses another question. Let's say I own a plane or buy a plane with two KX170s and a VFR-only GPS. I buy the plane and, being an IFR pilot, I obviously want to upgrade to an IFR GPS. Given that this ADS-B seems to be coming and I will probably need it for the kind of flying I want to do, do I:

1) Upgrade the VFR-only GPS to an IFR GPS and then make a subsequent upgrade later?

2) Swap out the VFR-only GPS and a KX170 for a GNS430, and then make an upgrade?

3) Leave the stack alone, and upgrade it once ADS-B stuff gets implemented?

 

[Joe B]

Let's say I own a plane or buy a plane with two KX170s and a VFR-only GPS. I buy the plane and, being an IFR pilot, I obviously want to upgrade to an IFR GPS. Given that this ADS-B seems to be coming and I will probably need it for the kind of flying I want to do, do I:

1) Upgrade the VFR-only GPS to an IFR GPS and then make a subsequent upgrade later?

2) Swap out the VFR-only GPS and a KX170 for a GNS430, and then make an upgrade?

3) Leave the stack alone, and upgrade it once ADS-B stuff gets implemented?

Given that you "obviously want to upgrade to an IFR GPS", go ahead and do so. You'll receive immediate benefit. As far as industry can tell a WAAS-certified IFR GPS will be able to drive any ADS-B equipment envisioned by the FAA. You'll have to add that equipment later, of course. It's less clear if you'll be able to use a non-WAAS GPS under ADS-B. It was "no way" under the FAA's original proposed rule, but a number of commenters and the ARC report itself say "Easy there, pal". This question is very much in play still.

You pays your money and you takes your chances. Any IFR GPS will be an immediate benefit. Your choice #2 looks like a good entry into this realm. A WAAS-IFR GPS will cost a bunch more now but will cost less to upgrade to ADS-B later. It'll give you some immediate additional benefit (synthetic glideslopes on most RNAV approaches) right now, too. Did I mention it'll cost a bunch more? Buy for what fits your needs and your wallet now. No matter what you do, you're going back into that panel again sometime before 2020. But I don't think I'd wait 12 years to put in some kind of IFR GPS.

 

[gismo]

I'm surprised no one has brought up the issue of the two independent systems of ADS-B. If you have the GA version you won't get any information on the big iron and vice versa as I understand it unless you install both systems (at more than double the cost). AOPA was fighting this, did they win on that issue already?

 

[Bob Noel]

What's the expected useful life of the equipment? Would you have to upgrade/replace
the equipment anyway when ADS-B is eventually required for real?

 

[jmaynard]

do I:

1) Upgrade the VFR-only GPS to an IFR GPS and then make a subsequent upgrade later?

2) Swap out the VFR-only GPS and a KX170 for a GNS430, and then make an upgrade?

3) Leave the stack alone, and upgrade it once ADS-B stuff gets implemented?

I'd suggest a variant of 2): swap out the VFR-only GPS and a KX170 for a GNS430W. That will satisfy the GPS requirement for ADS-B Out, since it has WAAS. At that point, you only need to add the UAT transmitter, or a GTX330A (the ADS-B Out version - my guess as to the model name) to be in compliance. You might consider swapping the other KX170 for an SL30/40, just to get the cranky so-and-so out of your panel, but that can be deferred.

 

[jmaynard]

Did I mention it'll cost a bunch more? Buy for what fits your needs and your wallet now.

Actually, the GNS430W's new price is about what the new price of the GNS430 was before the W was introduced. As it is, however, you can't buy a non-WAAS 430 new any more anyway.

 

[Walt]

Ted,
You have some good input so far. I would add that GPS equipment has about a 5 yr. half life. A system bought today, will continue to work for many years but the GPS designers will add new features to their new models and you will want to upgrade. Buying used would be a good idea except that the installation cost is so high. After a few years you will want or have to upgrade. The new unit will have an installation cost. Their is no best answer to your dilemma. How ADS-B will play into your future equipment needs is not yet clear. I am waiting for that decision to be made before I do any upgrading.

 

[sba55]

I'm surprised no one has brought up the issue of the two independent systems of ADS-B. If you have the GA version you won't get any information on the big iron and vice versa as I understand it unless you install both systems (at more than double the cost). AOPA was fighting this, did they win on that issue already?

Lance,

I didn't even know about this. Do you have any more details?

What surprises me is that there seems to be less concern over the loss of flight following and the fact that some planes just won't be visible anymore than I expected. To me, that seems like a killer (literally) issue....

I wish AOPA and all the other groups would step up and say flat out that any ADS-B in its current form is a terrible idea. Right now, they're just sort of complaining about specific problems...

-Felix

 

[Ted]

I'd suggest a variant of 2): swap out the VFR-only GPS and a KX170 for a GNS430W. That will satisfy the GPS requirement for ADS-B Out, since it has WAAS. At that point, you only need to add the UAT transmitter, or a GTX330A (the ADS-B Out version - my guess as to the model name) to be in compliance. You might consider swapping the other KX170 for an SL30/40, just to get the cranky so-and-so out of your panel, but that can be deferred.

I actually have no problem with the old clacky KX170s, and keeping one around is cost-effective, especially if it comes with two (and I therefore have a spare). But hey that's me, and your plane has a more technologically advanced stack than I expect to have in whichever plane I buy.

Despite the implication, I don't actually have any specific airplane in mind, but as I'm getting ramped up for the tire kicking, it's something to think about as I am evaluating perspective planes.

 

[flyingcheesehead]

You might consider swapping the other KX170 for an SL30/40, just to get the cranky so-and-so out of your panel, but that can be deferred.

Right on Jay... However, if you want to save some money, rather than buying an SL30 or KX155, get a MAC 1700. It's a rebuild of the King (which is really a very good radio except for that cranky mechanical tuning) which has not only flip-flop but memory for something like 8 com and 8 nav frequencies that you can cycle through:

(It's the one below the 430 with the pretty terrain picture on it )

EDIT: I forgot to mention WHY the MAC 1700 saves you money: It's a slide-in replacement for the KX170/175 radios. No avionics shop needed.

 

[gismo]

Lance,

I didn't even know about this. Do you have any more details?

What surprises me is that there seems to be less concern over the loss of flight following and the fact that some planes just won't be visible anymore than I expected. To me, that seems like a killer (literally) issue....

I wish AOPA and all the other groups would step up and say flat out that any ADS-B in its current form is a terrible idea. Right now, they're just sort of complaining about specific problems...

-Felix

There are two incompatible methods for airplanes to broadcast their position in the American system, 1090ES and UAT. 1090ES is only expected to be implemented on jets and large airplanes and UAT is the preferred (lower cost) solution for the rest of us. Neither system is able to receive positions from the other but in major terminal areas (i.e. Class B) ground equipment will translate from one format to the other. But anywhere else one group of airplanes will be electronically blind to the other. This just doesn't seem like a good idea to me.

 

[Ted]

Right on Jay... However, if you want to save some money, rather than buying an SL30 or KX155, get a MAC 1700. It's a rebuild of the King (which is really a very good radio except for that cranky mechanical tuning) which has not only flip-flop but memory for something like 8 com and 8 nav frequencies that you can cycle through:

(It's the one below the 430 with the pretty terrain picture on it )

The Mooney has one of those MAC 1700s in it. Now that I've gotten used to it it's not too bad, but that frequency storage thing is completely useless to me, and it took me a little getting used to. Your mileage may vary.

Out of the three airplanes I fly, all three of them have dual KX170s of some nature, be it a standard or a rebuild such as the MAC 1700, or another such digital setup. I'm happy with them.

 

[sba55]

There are two incompatible methods for airplanes to broadcast their position in the American system, 1090ES and UAT. 1090ES is only expected to be implemented on jets and large airplanes and UAT is the preferred (lower cost) solution for the rest of us. Neither system is able to receive positions from the other but in major terminal areas (i.e. Class B) ground equipment will translate from one format to the other. But anywhere else one group of airplanes will be electronically blind to the other. This just doesn't seem like a good idea to me.

Thanks Lance. We're doomed. So you'd be able to see even less airplanes than I thought if you're VFR and not getting flight following. Time to start freaking out...

So if you fly VFR from time to time, you'll basically be forced to get ADS-B in. I know that I won't fly if I can't get traffic advisories nor see the traffic myself.

Also, let's say you have an emergency during a VFR flight. You don't have ADS-B at all. After calling up 121.5, you get to read your position to them, but they can't track you. Tough.

Is there anything good about ADS-B? The more I think about it, the more it seems like a generally horrible idea....

 

[jmaynard]

There are two incompatible methods for airplanes to broadcast their position in the American system, 1090ES and UAT. 1090ES is only expected to be implemented on jets and large airplanes and UAT is the preferred (lower cost) solution for the rest of us.

...which makes me chuckle, since I'll be using 1090ES with my upgraded GTX330... (1090ES is basically mode S on steroids.)

 

[Steve]

Garmin had this press release at Airventure this year.

http://garmin.blogs.com/pr/2008/07/garmins-avionic.html?activeBranchId=newsroom

Here is an excerpt.

Garmin was the first company to certify and deploy ADS-B avionics for both air transport and general aviation customers:

• The GDL® 90 is aviation’s first certified ADS-B UAT datalink transceiver. Designed as a remote-mounted unit, the GDL 90 broadcasts position, velocity and vector information and receives ground and air based data and transfers that data in the form of real-time weather, traffic and TFRs to the Garmin GMX 200 multi-function display. The GDL 90 is the first TSO C154-certified Universal Access Transceiver (UAT) and includes a TSO C145a WAAS GPS sensor that offers outstanding position accuracy and integrity. Garmin has delivered over 1,800 GDL 90 transceivers since the first delivery in 2004.
• In addition to the GMX 200, other cockpit display of traffic information (CDTI) options for the GDL 90 include the G1000 integrated flight deck, the popular GNS™ 430 and GNS 530 panel mount products as well as the GPSMAP® 396 and 496 portable products.
• Garmin recently announced the GTX™ 330 and GTX 33 transponders with 1090 MHz extended squitter (ES) capabilities that are ADS-B compatible, so that general aviation aircraft can automatically transmit position, velocity and heading information. The 1090 MHz ES (TSO-C166a) builds upon the existing system by transmitting pertinent aircraft information independent of being interrogated.

Since I have a Garmin stack I really haven't looked at other vendors for compatibility.

Steve,
I looked with interest at Boeing's remarks. The phasing of ADS-B does not concern me as much as the equipment required. I was wondering if you have determined if a 430W will meet the proposed regulations and if you know whether GPS's meeting TSO 129 will qualify. The biggest cost of complying with this proposal will be buying and installing a new WAAS GPS. It will also take a new transponder. I understand the FAA has sent the avionics industry the proposed regulations including proposed maintenance regulations. This means everything is can change but I would appreciate the any information you have dug up.
Thanks

 

[Joe B]

There are two incompatible methods for airplanes to broadcast their position in the American system, 1090ES and UAT. 1090ES is only expected to be implemented on jets and large airplanes and UAT is the preferred (lower cost) solution for the rest of us. Neither system is able to receive positions from the other but in major terminal areas (i.e. Class B) ground equipment will translate from one format to the other. But anywhere else one group of airplanes will be electronically blind to the other. This just doesn't seem like a good idea to me.

The original NPRM says that all of the ADS-B ground stations will perform this conversion from one format to another, and that they expect the same airspace coverage as current radar (including Center radar). So there will be a huge area of ADS-B coverage - orders of magnitude greater than current TIS. But you are correct, there will still be pretty big holes and the system is vulnerable to ground equipment failure. My preference would be to skip this silly (and expensive) ground repeater stuff and install a receiver in my aircraft which can pick up ADS-B on both frequencies. I'd happily replace my transponder and TCAD with that once ADS-B is widely adopted.

I've only had time to read the Executive Summary of the ARC Report(*) thus far. It does tell the FAA that dual frequencies for ADS-B is a bad idea. It doesn't seem to hold a lot of promise for getting to a single-frequency solution anytime soon, though.

GA also needs to be aware of the strategic problem with dual frequencies: All the airlines will be on one frequency, GA will be on the other. The infrastructure for the second frequency as well as the repeaters to translate between frequencies are potentially billable directly to GA. This will be huge ammunition in favor of user fees.

...since I'll be using 1090ES with my upgraded GTX330...

I hope it works out that way but I'm not betting real money on it. Both technical standards and rules are still in flux. Given the saturation which is already occurring on the 1090 band it's possible one may not be allowed to install 1090ES unless one operates in the flight levels.

I wish AOPA and all the other groups would step up and say flat out that any ADS-B in its current form is a terrible idea. Right now, they're just sort of complaining about specific problems...

Felix, in all fairness to AOPA their first comment on the ADS-B NPRM was "The proposed rule is not acceptable in its current form."

* I can't figure out how to get a link right to the ARC report, but go to www.regulations.gov and search for FAA-2007-29305 then select "other documents" and it'll be at the top of the list.