Robert M. Gary wrote:
On Mar 26, 9:33 am, scott moore wrote:
Mode-S/TIS transponders cost more, turns out, they cost
substantially more to certify for IFR as well. I'm beginning to come
around to the viewpoint of those here who say that any modernization
that comes from the FAA will usually be a costly waste of time. The
FAA is abandoning TIS slowly, and would have done it fast if we and
the AOPA hadn't complained about it.

Now I fully well expect ADS-B to be held hostage to the FAA's funding
scam:

================================================== ===================
FAA: Funding Tied To Modernization

The FAA must implement changes to the way it is funded before it can
afford to embrace the myriad technologies that are envisioned for the
Next Generation Air Transportation System, according to senior FAA
staffers. Appearing before the Senate aviation subcommittee, Charles
Leader, director of the Joint Planning and Development Office, told
committee members that the controversial system of user fees and tax
increases now under consideration by Congress for FAA reauthorization is
a key element of FAA modernization. "Modernization and moving to NextGen
is inextricably linked to changes in the FAA's financing system," Leader
said.
================================================== ======================

I guess we can expect the FAA to axe or radically slow down ADS-B in
retaliation for not getting what they want. It would not work in any
case. The attempt to shift costs to GA would yield less than the present
system on day one, and rapidly decline as GA users bailed out of
aviation or cut back on operations.

Scott Moore

Our 182T has TIS. Its a very nice system but it doesn't seem very
necessary in the face of ADS-B.

-Robert


Let's go over this right quick. The FAA issued the TIS system, a bunch
of manufacturers (ok, damm few manufacturers) bit the bait and built
such a unit. Then the FAA cancellated it.

Now the FAA is a' saying that in orders to get ADS-B out there, they
needs to get deep, deep into your pockets.

Now tell me exactly why you think the FAA is going to hold ADS-B
sacred.

Now whilst you are thinking about that, think about this. Why would it
matter, to the ADS-B "cause" per sey, if the FAA should suddenly fall
into an economic sink hole and die?

Let's say, just say, that the FAA disappeared. WAAS would die, right?
Why? Well, that there satellite needs operation and maintenence. VORs,
ILSes and the rest would go for the same reason.

What would ADS-B do? Die? Why? Think hard before you answer.

What ADS-B does is give two black boxes, approaching each other,
the ability to see each other. They do this the most direct way
possible, by talking to each other via line of sight. In fact, its
the perfect application for two such boxes, because airplanes that
cannot see each other (have a direct line between them without
intervening obstacle) generally don't collide. In addition, these
boxes get more accurate relative to each other the closer they get,
again, just what you want in a collision avoidance system [1].

Now imagine that while your two airplanes are (or are not) colliding,
the FAA runs out of money. What occurs?

Nothing, right?

Well, that's the basic nature of the system. However, the FAA is not
real big on basic natures of things, so they rigged the system so that
they are between those two black boxes. Now this is a fairly interesting
trick. How could the FAA manage to be between two colliding airplanes?

Well, it works if FAA ground equipment is required to "translate"
between two completely different types of ADS-B. So lets say, just
say, that if you were stupid, greedy or both, you would design the
system so that one group got ADS-B system type "A", and the other
got ADS-B system type "B". Well, then you would have, as the French
say a "voila". There would be no way the system could work unless
you translate system A to system B, and B to A, etc. And you would
need ground stations to do that. Then you would be needed and
loved because you owned them nice ground stations without fer which
them A and B airplane types would be a collidin' all overs the place.

Now that leaves a big what if. If you are a genius A-B system designer
dude, you need to have at least one of them thar A or B folks agree
not to fly out of the range of a ground station, or even the line
of sight thereof. Otherwise, you would get one of those A folks,
and one of them B folks, out of the line of sight, behind a
mountain where they would collide and start blaming the FAA.

And so the pieces to the puzzle all fit together. The FAA designs
ADS-B not to work without them. ADS-B boxes, expensive or cheap are
the pilot's/airplane owners problem to purchase, and the FAA's part in
it was pretty much done after the design of the thing was worked out
(hint: the FAA didn't have much to do with that, either). But those
"required" ground based systems prevent all them ADS-B boxes from
all talking to each other, and cutting the FAA out of the "action".

Of course, isn't the idea ridiculous on it's face? Who would agree
to always fly in line of sight to a FAA ground station? If such a
group exists, why (oh why) would they agree to a system that keeps
the FAA in control, even if it is not only not necessary, but actually
harms the function of ADS-B (by preventing two ADS-B boxes from
contacting each other by direct line of sight)?

Who might this mysterious ADS-B "system A" group be?

I'll leave you with a big hint: They don't have any problem at all
with the proposed FAA funding scheme.

Scott.