http://www.avweb.com/eletter/archives/avflash/242-full.html#187369

How much longer are we supposed to be happy for a bunch of frozen
piper pilots on government technological welfare ?

If ADS-B saves lives, deploy it. Or shut the hell up. Just my
2 cents.

Scott Moore wrote:

> http://www.avweb.com/eletter/archives/avflash/242-full.html#187369
>
> How much longer are we supposed to be happy for a bunch of frozen
> piper pilots on government technological welfare ?
>
> If ADS-B saves lives, deploy it. Or shut the hell up. Just my
> 2 cents.

More stupid stuff that ****es me off:

http://www.faa.gov/asd/ads-b/06-07-02_ADS-B-Overview.pdf

The "final link decision" is "in", in a document that has the ability to
"copy" (cut and paste) disabled (thanks):

o Two ADS-B technologies are selected for use in the NAS: 109ES and UAT

o Aircraft that fly in high altitude airspace would equip with 1090ES

o General Aviation aircraft that are not capable of high altitude operations
would equip with UAT.

o Interoperability between the links will be provided within coverage of the
ground ADS-B infrastructure using the multilink gateway service provided via the
TIS-B uplink (ground to air).

Translation: BIG AIRCRAFT AND SMALL WON'T BE ABLE TO TALK TO EACH OTHER. Instead,
the data will all go through the FAA radar site.

Gee, I thought the whole idea of ADS-B was to get a system that didn't need to
depend on radar !

Further, this moronic doublespeak ignores that UAT is installed, let me think,
oh yea, NOWHERE OUTSIDE OF GOVERNMENT FUNDED TESTS IN GODDAM FROZEN NOPLACE.
Whereas a lot of us foolishly bought mode-s to get TIS DATA, which is how, by the
by, the "gateway" service the radar terminal provides is supposed to work.

This means: you bought mode-s to get TIS ? Yea, TIS is a good idea, but mode-s
ain't it. You messed up ! That'll teach you to try and predict what the FAA
will do !

Finally, yes you MAY use your mode-s for ADS-B - if you can prove you can fly
high in that thar airplane. Or perhaps private planes are supposed to carry
both, and switch over at a certain altitude ??!!!

Heres what really happened:

FAA: we want you all to use UAT. We spent big bucks funding it.

AIRLINES: No way. We already believed your last insipid line and bought
mode-s for everyone. We are staying mode-s.

FAA: well, we need SOME little defenseless aviation group to jam it to,
lets see.....

Typical beaurocrat nonsense. Try and give everyone what they want, and end up
screwing everyone.

Hey airlines, you didn't make out so good on the deal, either. You have
TWAS in spades to detect other large peices of metal, and even small
peices of metal. Say, does it make sense to make sure the little peices
of metal can't see you, even if you can see them ?

Also, yes, you big airplanes come and go with radar. How sure are you
that you will never encounter a light airplane outside the radar sphere ?
Radars go on the blink, as well, and they get shadowed by other airplanes
and mountains.

So what do you recommend? whats the solution?

Dave

Scott Moore wrote:

> Scott Moore wrote:
>
>> http://www.avweb.com/eletter/archives/avflash/242-full.html#187369
>>
>> How much longer are we supposed to be happy for a bunch of frozen
>> piper pilots on government technological welfare ?
>>
>> If ADS-B saves lives, deploy it. Or shut the hell up. Just my
>> 2 cents.
>
>
> More stupid stuff that ****es me off:
>
> http://www.faa.gov/asd/ads-b/06-07-02_ADS-B-Overview.pdf
>
> The "final link decision" is "in", in a document that has the ability to
> "copy" (cut and paste) disabled (thanks):
>
> o Two ADS-B technologies are selected for use in the NAS: 109ES and UAT
>
> o Aircraft that fly in high altitude airspace would equip with 1090ES
>
> o General Aviation aircraft that are not capable of high altitude
> operations
> would equip with UAT.
>
> o Interoperability between the links will be provided within coverage of
> the
> ground ADS-B infrastructure using the multilink gateway service provided
> via the
> TIS-B uplink (ground to air).
>
> Translation: BIG AIRCRAFT AND SMALL WON'T BE ABLE TO TALK TO EACH OTHER.
> Instead,
> the data will all go through the FAA radar site.
>
> Gee, I thought the whole idea of ADS-B was to get a system that didn't
> need to
> depend on radar !
>
> Further, this moronic doublespeak ignores that UAT is installed, let me
> think,
> oh yea, NOWHERE OUTSIDE OF GOVERNMENT FUNDED TESTS IN GODDAM FROZEN
> NOPLACE.
> Whereas a lot of us foolishly bought mode-s to get TIS DATA, which is
> how, by the
> by, the "gateway" service the radar terminal provides is supposed to work.
>
> This means: you bought mode-s to get TIS ? Yea, TIS is a good idea, but
> mode-s
> ain't it. You messed up ! That'll teach you to try and predict what the FAA
> will do !
>
> Finally, yes you MAY use your mode-s for ADS-B - if you can prove you
> can fly
> high in that thar airplane. Or perhaps private planes are supposed to carry
> both, and switch over at a certain altitude ??!!!
>
> Heres what really happened:
>
> FAA: we want you all to use UAT. We spent big bucks funding it.
>
> AIRLINES: No way. We already believed your last insipid line and bought
> mode-s for everyone. We are staying mode-s.
>
> FAA: well, we need SOME little defenseless aviation group to jam it to,
> lets see.....
>
> Typical beaurocrat nonsense. Try and give everyone what they want, and
> end up
> screwing everyone.
>
> Hey airlines, you didn't make out so good on the deal, either. You have
> TWAS in spades to detect other large peices of metal, and even small
> peices of metal. Say, does it make sense to make sure the little peices
> of metal can't see you, even if you can see them ?
>
> Also, yes, you big airplanes come and go with radar. How sure are you
> that you will never encounter a light airplane outside the radar sphere ?
> Radars go on the blink, as well, and they get shadowed by other airplanes
> and mountains.

Dave S wrote:
> So what do you recommend? whats the solution?
>
> Dave
>

I cleaned up my language a bit, then sent my tirade off to Phil Boyer :-)

He gave me a short note, then promised me an "in depth" note from their
staff expert on the subject. I believe the gist of it is that the AOPA
has fought tooth and nail to keep the mode-s requirement out of light
airplanes due to individual airplane ids and their potential for for
fees and misuse (imagine the "stop the noise" zelots having the ability
to get an N number automatically).

I don't mind adding a UAT, if that is what it takes. I mind the apparent,
from reading the FAA material, dogma that light airplanes shall have
UAT and big airplanes shall have mode-s, and the FAA shall act as the
bridge between the two (ha !).

All kinds of "what to do" things occur to me, but each seems to be
centered around a group with an interest who does not want to move.

o Allow "anonymous mode-s", and so remove the light pilot/AOPA objection
to mode-s ? This has been proposed many times in many places. Apparently
the FAA would rather die than this, but why are they (apparently) going
to allow UAT to so do, but not mode-s ?

o Require UAT on airlines, so that everyone speaks the same language, and
UAT eventually replaces mode-s as a more advanced method ? I could hardly
blame the airlines for fighting that one. The FAA just got through requiring
them to buy into mode-s. It would put the airlines into the position
of buying the "black box of the month" as the FAA changes with the wind.

o Require light airplanes to have both ? Time for us to scream, I guess, but
that is where I am headed anyways, since I was stupid enough to buy mode-s
(for TIS).

In any case, it appears that the FAA, the AOPA and the airlines have all
already come to the solution:

o Airlines have mode-s, we have UAT, and the friendly FAA will translate
between the two, but only under radar control (neatly severing the non-radar
reliant feature off ADS-B). The theory is, I guess, that airlines allways
travel under radar so it won't matter in any cass.

o Light airplanes unlucky enough to have high altitude capability would
need both mode-s and UAT. This would also apply to a huge number of
jets and even heavy aircraft, since there are a lot of light jets and
passenger aircraft servicing smaller, non-radar fields.

In short, it will be a mess, and the FAA has a plan, the beauty and
simplicity of which clearly escapes me.

"Say Tex, wasn't that a heavy that nearly ran us down ?"

"why yes, we need to turn our mode-s on ! And I think the UAT off ?
or is it mode-UAT ?"

"which one of them switches is that ?"

"never mind, they are gone anyways..."

In article <yjstc.9901$Ly.7087@attbi_s01>, Scott Moore
> wrote:

> o Allow "anonymous mode-s", and so remove the light pilot/AOPA objection
> to mode-s ? This has been proposed many times in many places. Apparently
> the FAA would rather die than this, but why are they (apparently) going
> to allow UAT to so do, but not mode-s ?

Mode-S doesn't have a provision for "anonymous." And changing
the specs for Mode-S would be, ahem, challenging. It's not
actually an FAA issue.


>
> o Require UAT on airlines, so that everyone speaks the same language, and
> UAT eventually replaces mode-s as a more advanced method ? I could hardly
> blame the airlines for fighting that one. The FAA just got through
> requiring
> them to buy into mode-s. It would put the airlines into the position
> of buying the "black box of the month" as the FAA changes with the wind.

bingo. The airlines had to install expensive tcas systems and
have to have Mode-S for that and other systems (for flight in Europe
and other areas). The airlines will fight tooth-n-nail requirements
to install duplicative systems.


> In any case, it appears that the FAA, the AOPA and the airlines have all
> already come to the solution:

not much of a solution...

--
Bob Noel

Bob Noel wrote:

> In article <yjstc.9901$Ly.7087@attbi_s01>, Scott Moore
> > wrote:
>
>
>>o Allow "anonymous mode-s", and so remove the light pilot/AOPA objection
>>to mode-s ? This has been proposed many times in many places. Apparently
>>the FAA would rather die than this, but why are they (apparently) going
>>to allow UAT to so do, but not mode-s ?
>
>
> Mode-S doesn't have a provision for "anonymous." And changing
> the specs for Mode-S would be, ahem, challenging. It's not
> actually an FAA issue.

Well, I do understand the issue, but not why anonymous is so hard. The
shop programs the N number, right ? What is to prevent them from declaring
a "universal" N number (the equivalent of 1200) and just programming all
"protestants" with that on request ?

>
>
>
>>o Require UAT on airlines, so that everyone speaks the same language, and
>>UAT eventually replaces mode-s as a more advanced method ? I could hardly
>>blame the airlines for fighting that one. The FAA just got through
>>requiring
>>them to buy into mode-s. It would put the airlines into the position
>>of buying the "black box of the month" as the FAA changes with the wind.
>
>
> bingo. The airlines had to install expensive tcas systems and
> have to have Mode-S for that and other systems (for flight in Europe
> and other areas). The airlines will fight tooth-n-nail requirements
> to install duplicative systems.
>
>
>
>>In any case, it appears that the FAA, the AOPA and the airlines have all
>>already come to the solution:
>
>
> not much of a solution...
>

"Scott Moore" > wrote in message news:otttc.5331$eY2.1195@attbi_s02...
> Well, I do understand the issue, but not why anonymous is so hard. The
> shop programs the N number, right ? What is to prevent them from declaring
> a "universal" N number (the equivalent of 1200) and just programming all
> "protestants" with that on request ?

The shop doesn't program N-number. They program a mode S id that corresponds
to the N number in the FAA database. I'm not sure mode S is prepared to deal with
duplicate ID's so you just can't set them to blank, you'd need unique anonymous ID's.

"Ron Natalie" > wrote in message =
. ..
>=20
> "Scott Moore" > wrote in message =
news:otttc.5331$eY2.1195@attbi_s02...
> > Well, I do understand the issue, but not why anonymous is so hard. =
The
> > shop programs the N number, right ? What is to prevent them from =
declaring
> > a "universal" N number (the equivalent of 1200) and just programming =
all
> > "protestants" with that on request ?
>=20
> The shop doesn't program N-number. They program a mode S id that =
corresponds
> to the N number in the FAA database. I'm not sure mode S is prepared =
to deal with
> duplicate ID's so you just can't set them to blank, you'd need unique =
anonymous ID's.
>=20

My Ryan TCAD displays the N-number of Mode-S aircraft.
It certainly has no access to the FAA database you mentioned.
If "the shop" doesn't program the N-number, who does?
---JRC---

No they don't. That is how it is supposed to work, but it doesn't. The shop
programs in the "N" number. My approval just came back from the FAA for the
Garmin 330.

Karl
"Ron Natalie" > wrote in message
. ..
>
> "Scott Moore" > wrote in message
news:otttc.5331$eY2.1195@attbi_s02...
> > Well, I do understand the issue, but not why anonymous is so hard. The
> > shop programs the N number, right ? What is to prevent them from
declaring
> > a "universal" N number (the equivalent of 1200) and just programming all
> > "protestants" with that on request ?
>
> The shop doesn't program N-number. They program a mode S id that
corresponds
> to the N number in the FAA database. I'm not sure mode S is prepared to
deal with
> duplicate ID's so you just can't set them to blank, you'd need unique
anonymous ID's.
>

Ron Natalie wrote:
> "Scott Moore" > wrote in message news:otttc.5331$eY2.1195@attbi_s02...
>
>>Well, I do understand the issue, but not why anonymous is so hard. The
>>shop programs the N number, right ? What is to prevent them from declaring
>>a "universal" N number (the equivalent of 1200) and just programming all
>>"protestants" with that on request ?
>
>
> The shop doesn't program N-number. They program a mode S id that corresponds
> to the N number in the FAA database. I'm not sure mode S is prepared to deal with
> duplicate ID's so you just can't set them to blank, you'd need unique anonymous ID's.
>

Dosen't a UAT have a similar requirement ?

I dont understand why anonymous is such a point of contention. You have
to have a license plate on your car, dont you? and an N number on your
plane? A mode S transponder is the electronic equivalent of a license
plate. Even if it DOES seem big brother-like. Flying is a priveledge,
which can be granted or disallowed. I am of the mindset that positive ID
while excercising that priveledge is perfectly acceptable.

Ok.. if they want to charge fee's for service.. then let them charge..
they do in europe, dont they? Of course, if it costs 100 bux to file a
flight plan, I would expect everyone to stop filing flight plans.. (I'm
sure a more reasonable (for GA) solution would be a fee based on seats
or gross weight).

And the "stop the noise" zealots already CAN get your N-Number. With a
Mark 1 Mod A optical sensor (Eyeball) and pair of binoculars. While I am
a member of AOPA and I do pay my dues, I really dont see how GA/AOPA
fighting mode S tooth and nail is really doing us any benefit. There are
other issues that are more important in my mind (controller shortages,
inconsistent enforcement and PFR's) and that need to be addressed.

Dave

Scott Moore wrote:
> Bob Noel wrote:
>
>> In article <yjstc.9901$Ly.7087@attbi_s01>, Scott Moore
>> > wrote:
>>
>>
>>> o Allow "anonymous mode-s", and so remove the light pilot/AOPA objection
>>> to mode-s ? This has been proposed many times in many places. Apparently
>>> the FAA would rather die than this, but why are they (apparently) going
>>> to allow UAT to so do, but not mode-s ?
>>
>>
>>
>> Mode-S doesn't have a provision for "anonymous." And changing
>> the specs for Mode-S would be, ahem, challenging. It's not
>> actually an FAA issue.
>
>
> Well, I do understand the issue, but not why anonymous is so hard. The
> shop programs the N number, right ? What is to prevent them from declaring
> a "universal" N number (the equivalent of 1200) and just programming all
> "protestants" with that on request ?
>
>>
>>
>>
>>> o Require UAT on airlines, so that everyone speaks the same language,
>>> and
>>> UAT eventually replaces mode-s as a more advanced method ? I could
>>> hardly
>>> blame the airlines for fighting that one. The FAA just got through
>>> requiring
>>> them to buy into mode-s. It would put the airlines into the position
>>> of buying the "black box of the month" as the FAA changes with the wind.
>>
>>
>>
>> bingo. The airlines had to install expensive tcas systems and
>> have to have Mode-S for that and other systems (for flight in Europe
>> and other areas). The airlines will fight tooth-n-nail requirements
>> to install duplicative systems.
>>
>>
>>
>>> In any case, it appears that the FAA, the AOPA and the airlines have all
>>> already come to the solution:
>>
>>
>>
>> not much of a solution...
>>

"Scott Moore" > wrote in message
news:yjstc.9901$Ly.7087@attbi_s01...>

> fees and misuse (imagine the "stop the noise" zelots having the ability
> to get an N number automatically).

This is already possible at least for IFR flights if you sign up for
www.fboweb.com and do an "Area Track" -- just enter a zip code and desired
radius and you will see all the IFR flights and their altitudes,
destinations, and registered owners.


--------------------
Richard Kaplan, CFII

www.flyimc.com

"Scott Moore" > wrote in message
news:yjstc.9901$Ly.7087@attbi_s01...>

> Light airplanes unlucky enough to have high altitude capability would
> need both mode-s and UAT. This would also apply to a huge number of

Do you know the definition of high-altitude capability?

A turbocharged piston airplane may very well be capable of flying above
FL300 although it is rare for piston airplanes to actually do so.


--------------------
Richard Kaplan, CFII

www.flyimc.com

Ok, what's a UAT? acronymfinder.com doesn't have it (or I don't recognize it
there)

Jose

--
(for Email, make the obvious changes in my address)

In article >,
(Teacherjh) wrote:

> Ok, what's a UAT? acronymfinder.com doesn't have it (or I don't
> recognize it
> there)
>
> Jose


Universal Access Transceiver

a short briefing is at (watch out for the line wrap):
http://spacecom.grc.nasa.gov/icnsconf/docs/2001/CNS01_Session_B3-Dieudonn
e.pdf

--
Bob Noel

"Scott Moore" > wrote in message
news:otttc.5331$eY2.1195@attbi_s02...
> Bob Noel wrote:
>
> >
> > Mode-S doesn't have a provision for "anonymous." And changing
> > the specs for Mode-S would be, ahem, challenging. It's not
> > actually an FAA issue.
>
> Well, I do understand the issue, but not why anonymous is so hard. The
> shop programs the N number, right ? What is to prevent them from declaring
> a "universal" N number (the equivalent of 1200) and just programming all
> "protestants" with that on request ?

You're confusing the "Flight ID" variable with the ICAO 24-bit ID. For most
GA aircraft, both are programmed at install. The flight ID is set to the
N-number and the 24-bit ID is set. In air transport A/C, the Flight ID can
be set from the flight deck to reflect the current Flight ID.

The difference is that the Mode-S system doesn't care what the N-number or
Flight ID is (tho the controller might), it's just a variable to be
transmitted. The ICAO 24-bit ID is a different story. It is the "network"
address for your transponder. It is embedded in all Mode-S communications
to and from your transponder. For the system to work, the 24-bit IDs have
to be unique. For comparison, you can think of it as a hard-coded IP
address.

If you've done much network support, you'll know what kind of problems occur
when there are duplicate addresses in the system. To insure the system
works, ICAO assigned blocks of the 24-bit addresses to each member state,
who is then responsible for assigning them to specific aircraft. The FAA
assigns one to an aircraft when it is registered (whether it has a Mode-S
transponder or not). Look in the registry database if you want to know
yours.

The problem with 'anonymous' IDs is managing them so that you can have a
randomly assigned ID without a chance of duplication. You could conceivably
create some Mode-S equivalent to DHCP, but that is a) non-trivial, and b)
wouldn't necessarily provide anonymity. In the end, it would be a lot of
work for a feature that would just make the units more expensive to satisfy
a small vocal segment of the customer base.

Gerry

"Scott Moore" > wrote in message
news:yjstc.9901$Ly.7087@attbi_s01...
>
> I cleaned up my language a bit, then sent my tirade off to Phil Boyer :-)
>
> He gave me a short note, then promised me an "in depth" note from their
> staff expert on the subject. I believe the gist of it is that the AOPA
> has fought tooth and nail to keep the mode-s requirement out of light
> airplanes due to individual airplane ids and their potential for for
> fees and misuse (imagine the "stop the noise" zelots having the ability
> to get an N number automatically).

True. Cost is also an issue.

> I don't mind adding a UAT, if that is what it takes. I mind the apparent,
> from reading the FAA material, dogma that light airplanes shall have
> UAT and big airplanes shall have mode-s, and the FAA shall act as the
> bridge between the two (ha !).

It's not FAA dogma. It's a reasonable compromise to gain concensus from two
diverse groups, each of which has its own needs within the airspace. The
FAA actually hasn't mandated either one for any specific group. The
statement that GA will have UAT and airliners have 1090ES, is merely a
generalization of expected market response. There is nothing that requires
anyone to select one over the other. Nor is there anything that prevents
you from equipping with both.

> All kinds of "what to do" things occur to me, but each seems to be
> centered around a group with an interest who does not want to move.
>
> o Allow "anonymous mode-s", and so remove the light pilot/AOPA objection
> to mode-s ? This has been proposed many times in many places. Apparently
> the FAA would rather die than this, but why are they (apparently) going
> to allow UAT to so do, but not mode-s ?

Mode-Select (Mode-S) was designed twenty years ago for a very specific set
of needs. It does that very well. It is an addressed communication system.
Trying to make it do something for which it wasn't designed could compromise
the system or at best add a lot of expense and complexity.

UAT was created about 8 years ago specifically to support ADS-B, TIS-B, and
FIS-B. Note the "-B" in all the systems -- that stands for broadcast. UAT
is a non-addressed broadcast system. Basically it's a half-duplex radio
modem. When you transmit, you have no ability to determine who is
receiving. Likewise, in receive, you'll receive anybody within range.

> o Require UAT on airlines, so that everyone speaks the same language, and
> UAT eventually replaces mode-s as a more advanced method ? I could hardly
> blame the airlines for fighting that one. The FAA just got through
requiring
> them to buy into mode-s. It would put the airlines into the position
> of buying the "black box of the month" as the FAA changes with the wind.

Airlines have Mode-S because it's a required part of a TCAS system, which is
mandated. TCAS will not be going away. ADS-B may augment TCAS, but it
won't replace it. Adding ADS-B to the Mode-S system is the most
cost-efficient route if you already have the Mode-S/TCAS equipment.

> o Require light airplanes to have both ? Time for us to scream, I guess,
but
> that is where I am headed anyways, since I was stupid enough to buy mode-s
> (for TIS).

As I said before, you're not required to have either one. And I wouldn't
say you are stupid for buying into Mode-S for TIS. TIS is a very good
service. While it is limited to areas of Mode-S radar coverage, it allows
you to see any aircraft the radar is capable of tracking. While ADS-B
doesn't need radar, if the other guy isn't equipped, he's invisible.

> In any case, it appears that the FAA, the AOPA and the airlines have all
> already come to the solution:
>
> o Airlines have mode-s, we have UAT, and the friendly FAA will translate
> between the two, but only under radar control (neatly severing the
non-radar
> reliant feature off ADS-B). The theory is, I guess, that airlines allways
> travel under radar so it won't matter in any cass.

Major point here. The ADS-B repeater/translator is NOT radar based. It is
a 1090MHz receiver and a UAT receiver to "collect" ADS-B broadcsts from
aircraft in the vicinity. The data is then broadcast out on both 1090 MHz
and UAT (this broadcast is called TIS-B -- this is not the TIS you currently
have.) These are relatively cheap (a couple orders of magnitude cheaper
than a radar) autonomous ground stations that can be stuck pretty much
anywhere, including places where there is no radar coverage. This is
exactly what they did in Alaska for Capstone.

> o Light airplanes unlucky enough to have high altitude capability would
> need both mode-s and UAT. This would also apply to a huge number of
> jets and even heavy aircraft, since there are a lot of light jets and
> passenger aircraft servicing smaller, non-radar fields.

No. You can pick one, or neither, or both. While you may need a basic
Mode-S transponder for some high altitude airspace (RVSM), that does not
mean you have to have a 1090ES ADS-B system.

A fine point here. Your GTX330 is a long way from a 1090ES ADS-B system.
It currently provides only elementary surveillance support. It would
require an upgrade to support full ADS-B broadcast. Once you did that, you
could provide ADS-B broadcasts, but you'd still have to get a 1090 MHz
receiver to be able to receive ADS-B or TIB-B over 1090. (Your TIS data
comes up from the ground radar on 1030 MHz using the Mode-S comm-b
protocol.) Adding that receiver will not be cheap. The receiver and
transponder upgrade will likely cost as much or more than a UAT.

Gerry

Gerry Caron wrote:
> "Scott Moore" > wrote in message
> news:otttc.5331$eY2.1195@attbi_s02...
>
>>Bob Noel wrote:
>>
>>
>>>Mode-S doesn't have a provision for "anonymous." And changing
>>>the specs for Mode-S would be, ahem, challenging. It's not
>>>actually an FAA issue.
>>
>>Well, I do understand the issue, but not why anonymous is so hard. The
>>shop programs the N number, right ? What is to prevent them from declaring
>>a "universal" N number (the equivalent of 1200) and just programming all
>>"protestants" with that on request ?
>
>
> You're confusing the "Flight ID" variable with the ICAO 24-bit ID. For most
> GA aircraft, both are programmed at install. The flight ID is set to the
> N-number and the 24-bit ID is set. In air transport A/C, the Flight ID can
> be set from the flight deck to reflect the current Flight ID.
>
> The difference is that the Mode-S system doesn't care what the N-number or
> Flight ID is (tho the controller might), it's just a variable to be
> transmitted. The ICAO 24-bit ID is a different story. It is the "network"
> address for your transponder. It is embedded in all Mode-S communications
> to and from your transponder. For the system to work, the 24-bit IDs have
> to be unique. For comparison, you can think of it as a hard-coded IP
> address.
>
> If you've done much network support, you'll know what kind of problems occur
> when there are duplicate addresses in the system. To insure the system
> works, ICAO assigned blocks of the 24-bit addresses to each member state,
> who is then responsible for assigning them to specific aircraft. The FAA
> assigns one to an aircraft when it is registered (whether it has a Mode-S
> transponder or not). Look in the registry database if you want to know
> yours.
>
> The problem with 'anonymous' IDs is managing them so that you can have a
> randomly assigned ID without a chance of duplication. You could conceivably
> create some Mode-S equivalent to DHCP, but that is a) non-trivial, and b)
> wouldn't necessarily provide anonymity. In the end, it would be a lot of
> work for a feature that would just make the units more expensive to satisfy
> a small vocal segment of the customer base.
>
> Gerry
>
>

Its simple. An installing shop gets a block of numbers to issue, then gets
another block when the numbers run out. And they keep no record of the
numbers. There is a need for the numbers to be unique, but they don't have
to be indicative of the particular aircraft. Even if the FBI or whatever
insists they have to be trackable, they can be kept on the books of the
installer to be revealed by court order. As it is, publishing them online
sure isn't going to be anonymous, but that system is easily changed. We
aren't out of numbers, and you could request a change to an anonymous id,
while turning your current ID back in, to be added back to the pool.

The system won't change because the FAA and powers that be don't want it
to change.

Again, I doubt the working requirements of a UAT are much different. It
probally has a need for a unique code as well.

Gerry Caron wrote:

> Mode-Select (Mode-S) was designed twenty years ago for a very specific set
> of needs. It does that very well. It is an addressed communication system.
> Trying to make it do something for which it wasn't designed could compromise
> the system or at best add a lot of expense and complexity.
>
> UAT was created about 8 years ago specifically to support ADS-B, TIS-B, and
> FIS-B. Note the "-B" in all the systems -- that stands for broadcast. UAT
> is a non-addressed broadcast system. Basically it's a half-duplex radio
> modem. When you transmit, you have no ability to determine who is
> receiving. Likewise, in receive, you'll receive anybody within range.
>

mode-s ("squitter") is also designed with these properties. The proposal to
add ads-b to mode-s originally had the mode-s transmitter start transmitting
asyncronously if the unit was not swept within a given period of time. Ie.,
lacking radar, the unit would switch to true ads-b mode.


> Airlines have Mode-S because it's a required part of a TCAS system, which is
> mandated. TCAS will not be going away. ADS-B may augment TCAS, but it
> won't replace it. Adding ADS-B to the Mode-S system is the most
> cost-efficient route if you already have the Mode-S/TCAS equipment.

I would say that at this state of the technology, that mode-s is going to be
the most cost effective for everyone. UAT is brand new, untried technology.
mode-s already has a lot of units and support. UAT is simply going to cost
more, for a while.

Having a defacto requirement that you need both mode-s and UAT on a light
airplane is certainly not going to help costs for light airplanes. And it
will be the defacto requirement once pilots find out they really should
have both to prevent being run over by a transport aircraft under all
conditions, including no radar and radar shadows.


> Major point here. The ADS-B repeater/translator is NOT radar based. It is
> a 1090MHz receiver and a UAT receiver to "collect" ADS-B broadcsts from
> aircraft in the vicinity. The data is then broadcast out on both 1090 MHz
> and UAT (this broadcast is called TIS-B -- this is not the TIS you currently
> have.) These are relatively cheap (a couple orders of magnitude cheaper
> than a radar) autonomous ground stations that can be stuck pretty much
> anywhere, including places where there is no radar coverage. This is
> exactly what they did in Alaska for Capstone.

Still means that you need a ground based translator to get from light airplanes
to transport aircraft. ADS-b's best feature was that it didn't need to depend
on ground stations. That ground station adds a new point of failure to the
system, as well as being a fickle one. I don't care how high tech digital
you get, that signal is not going to go through a mountain, whereas I have
never heard of a midair collision where the colliding aircraft went through
a mountain, ie., generally you have line of sight for an aircraft you are
colliding with.

>
>
>>o Light airplanes unlucky enough to have high altitude capability would
>>need both mode-s and UAT. This would also apply to a huge number of
>>jets and even heavy aircraft, since there are a lot of light jets and
>>passenger aircraft servicing smaller, non-radar fields.
>
>
> No. You can pick one, or neither, or both. While you may need a basic
> Mode-S transponder for some high altitude airspace (RVSM), that does not
> mean you have to have a 1090ES ADS-B system.

When ADS-B is required on class A airspace, then high altitude light planes
are going to need it as well. Unless you can think of a class A requirement
that was excepted for light aircraft ?

>
> A fine point here. Your GTX330 is a long way from a 1090ES ADS-B system.
> It currently provides only elementary surveillance support. It would
> require an upgrade to support full ADS-B broadcast. Once you did that, you
> could provide ADS-B broadcasts, but you'd still have to get a 1090 MHz
> receiver to be able to receive ADS-B or TIB-B over 1090. (Your TIS data
> comes up from the ground radar on 1030 MHz using the Mode-S comm-b
> protocol.) Adding that receiver will not be cheap. The receiver and
> transponder upgrade will likely cost as much or more than a UAT.
>
> Gerry
>
>

Good point (didn't know that), but it isn't going to change the fact that you
will need both systems. No, the airlines are not going to care, they simply
want uncontrolled airplanes out of their way no matter what. But as the
ramifications of having two "separate but equal" ADS-B systems work in,
its going to be understood that you better have both systems to be really
safe.

I disagree that it had to be this way. The FAA cannot even create one standard
for a brand new system ? No, what they did is throw a special interest party,
and give everyone what they wanted (even though they don't work together).

It stinks. Sorry, it just does.

"We like standards. In fact, we like them so much we think everyone should
have their own..."