Trust and Faith in the Feds?- Off-shoot from EAA/FAA Agreement

[MEdwards]

Hi, Jim. I agree, no heat here. First off, rereading I see I did indeed insult you by saying you didn't look out the window (although that was not exactly my intent). I was trying to make a point, but I made it at your expense. I apologize for that. In your first msg you said you didn't see it, which to me implies you were looking. Wes is right of course, the other a/c could have been almost anywhere. I've missed seeing even called traffic many times.

Since you asked around (with varying success) you now know what the deal is. For other readers, I'll quote the last bit of the section on traffic in the GDL39 user's manual: "The FAA ground station will only broadcast TIS-B traffic that is within ±15 NM and ±3500 feet of an aircraft with ADS-B Out. To get the full benefits of ADS-B traffic it is recommended that the aircraft be equipped with an ADS-B transmitter..." [...such as these fine products by Garmin!].

That's the "what." I researched a whole lot last night and I could not find the "why." TIS-B (which is the acronym that sends the traffic data) isn't something you just turn on/off with a switch like selective availability in early GPS days. It was designed from the start as a client/server relationship where you only get data if you ask for it. And you ask for it via ADS-B Out. I'm pretty sure the reason is bandwidth limitations. I can visualize capacity problems with broadcasting every radar target within (say) 50 miles of an ADS-B tower, but I don't have any numbers to back that up. As an engineer I would like to believe the design was based on rational engineering factors, not on the FAA as Evil Incarnate. But I could not find on the internet any discussion of the design rationale. I'm still looking.

[Jim Rosenow]

Hi, Wes

I think your quote is from me, and it's a term I've heard used. I'm reading a wikipedia article....

https://en.wikipedia.org/wiki/ADS-B

...as we speak, and they're calling it TIS-B instead. Not sure who authored the article, and as noted at the top there may be some issues with it. There's a lot out there to be read on the subject.

I hope someone starts asking these questions at Sun n Fun!

Jim

[MEdwards]

"what's turned off is ADS-R (re-broadcast)" So for anyone going to Oshkosh this summer, here is a question for you to vocalize at the "Meet The Administrator" session. "Why is the FAA intentionally holding back the ADS-R ...

Well, if you're going to ask loudly, then let's make sure we ask accurately, so they can't dodge the question.

What's "turned off" is TIS-B. Traffic Information Service-Broadcast. ADS-R is something different: There are two ADS-B frequencies. Some ADS-B receivers operate on only one of them. ADS-R is having the ground station rebroadcast on one frequency an ADS-B message originally transmitted on the other, so everybody receives it. It actually has nothing to do with TIS-B.

As stated in another msg, I would argue that it isn't "turned off." I don't think there's a switch. I think it was designed that way. Make them justify that design, which almost everybody would agree isn't in the best interests of safety.

[Jim Rosenow]

Mike,

First, thanks for the apology. Perhaps I should have stated more clearly in the initial post that we were heads-up. After all these years, it's just second-nature for us, to the point we make a verbal call when going heads-down.

Second, it's great to have an engineer/sleuth on the case. Please keep the information coming. The 'why' would be very interesting to know. Please keep us in the loop on your findings.

For FAA engineers to design a system, even given engineering constraints, that 99% (my guess, based on the air-to-air contacts we see) of current users can't access seems.....lordy, how do I finish THAT sentence in polite company...guess I won't, fill in your own ending. Evil Incarnate?...naaah...substitute stupid maybe.

Sad thing is, there are a LOT of aircraft that will NEVER be able to access this system (as it stands). Properly done, with a passive ADSB receiver and a tablet computer, they would have been able to for less than a grand.

Thanks for your efforts, Mike

Jim

[MEdwards]

Impressive you and your wife have together a very professional attitude (and behavior) about your flying.

A thought about ADS-B traffic and "heads up/down." I have a hunch when more people have traffic displayed on their panel or GPS or iPad, it's going to get worse. A msg on one board said a guy who recently added traffic is now scared to fly because he sees how many planes are around him.

I had a similar experience, in a more minor way, flying around Phoenix to the south last fall. Even though I don't have ADS-B Out, I was picking up direct transmissions from equipped aircraft (perhaps trainers--I understand some of the big training outfits like those around Phoenix have already equipped with ADS-B Out)--or I suppose it could have been a TIS-B broadcast meant for somebody else, I don't know how to tell the difference.

Anyway, there were a whole lot of airplanes out there, right where I was headed. I was taken aback and spent more time than I should have figuring out their tracks and whether they really were above/below me, and what I should do about it. All that time I was staring at the iPad, not at the sky in front of me. Not good.

[Jim Rosenow]

Impressive you and your wife have together a very professional attitude (and behavior) about your flying.

Thank you, sir! My wife is a Citation Captain and we emulate as best we can her work cockpit environment. Now if we could just get that speed!

I just read an article that said ERAU has UAT ADS-B Out in all their aircraft..that's probably your source out Phoenix way.

Agreed...it might be scary to know how many near-misses we DIDN'T know about! Just ONE freaked us out completely!

Keep us in the loop!...and I'm digging also.

Jim

[WLIU]

I guess that I do not "get" that folks who will zoom down the freeway at 80mph right next to another car or truck get really concerned when in the air they can observe another airplane within a mile of them. I understand wanting to be situationally aware, but there seems to be an undercurrent that suggests that the other pilots can't be trusted to hold up their end of the see and avoid. Pilots are much more organized, motivated, and aware than the average freeway driver. Anyone can drive on the freeway and you don't even have to have a medical.

The technology is great, but I will note that glass cockpits have not lived up to the advertising that they would greatly increase safety. We just see different accidents. So the next question is whether knowing that all of these other airplanes are around will help us avoid each other or not. The answer is unclear at this point.

In the interest of full disclosure, I work with computers and my observation is that integrating computers with people is a challenge that often does not produce the desired result. And I don't even work to a government contract....

Best of luck,

Wes
N78PS

[MEdwards]

Wes, a lot of it is getting used to it. And I was not used to seeing that kind of display before that evening south of Phoenix.

I was fortunate to learn to fly at Santa Monica, back when it was a thriving airport. A great place to learn to fly. There was always somebody else in the pattern, planes would cut in front of you entering downwind, or fly their downwind on your wingtip, or turn base in front of you when you were on final, a jet turned base right across my downwind about a quarter mile ahead. You had to get used to these things, and you did.

[TedK]

And remember, the FAA is not happy until you are not happy.

Remind me again, what does the acronym FAA mean?

[WLIU]

"I think your quote is from me"

I have had an FAA Ops Inspector use that phrase. I think that it was a poor attempt at humor, but the actual origin of the phrase "We're not happy until you're not happy" is likely lost in the mists of history.

Best of luck,

Wes
N78PS