Transponder Landing System ???

"Gerry Caron" wrote in message ...

It works by using a Mode A interrogator and multiple receivers around the
periphery of the airport. By measuring the time difference of arrival
(TDOA) of your transponder replies, it calculates your position relative to
the airport and the approach path. It then broadcasts thru an omni antenna
an "ILS" signal modulating the 90 and 150 Hz tones to drive your CDI to
indicate the proper guidance to the approach path.

Fascinating the things people thought up back in the days before a
constellation of satellites could provide a 3D positional fix with an
accuracy measured in inches.

With WAAS underway, it seems predictable that non-precision approaches
will be joining colored airways in the dustbin of history. If the FAA
had the resources and motivation it could probably be accomplished in
5 years, though I suppose 20 is more likely...

-cwk.

"Mike Rapoport" wrote in message thlink.net...

It isn't cheaper when you consider that it requires an operator.

Mike
MU-2

Does it require a dedicated operator, or can any old controller
hanging out in the tower run it? Out East I can't think of any Class D
fields that don't have at least 1 ILS, but perhaps in other regions
that's sometimes the case?

-cwk.

"C Kingsbury" wrote in message =
om...
"Gerry Caron" wrote in message =
...
=20
It works by using a Mode A interrogator and multiple receivers around =
the
periphery of the airport. By measuring the time difference of =
arrival
(TDOA) of your transponder replies, it calculates your position =
relative to
the airport and the approach path. It then broadcasts thru an omni =
antenna
an "ILS" signal modulating the 90 and 150 Hz tones to drive your CDI =
to
indicate the proper guidance to the approach path.
=20
Fascinating the things people thought up back in the days before a
constellation of satellites could provide a 3D positional fix with an
accuracy measured in inches.
=20
With WAAS underway, it seems predictable that non-precision approaches
will be joining colored airways in the dustbin of history. If the FAA
had the resources and motivation it could probably be accomplished in
5 years, though I suppose 20 is more likely...
=20
-cwk.

Five years? Twenty years?
Probably about a year ago, the FAA mentioned the rate at which they were
converting (IIRC) GPS approaches to LNAV/VNAV approaches.
The number sounded fairly good, until doing the math showed it would =
take
them about thirty years to finish the current number of runways at that =
rate.
---JRC---

A tower controller could do it but, like you say, there aren't many towered
fields without a low minimiums approach and no terrain issues. Generally it
is terrain that limits minimiums.

Mike
MU-2


"C Kingsbury" wrote in message
om...
"Mike Rapoport" wrote in message
thlink.net...

It isn't cheaper when you consider that it requires an operator.

Mike
MU-2

Does it require a dedicated operator, or can any old controller
hanging out in the tower run it? Out East I can't think of any Class D
fields that don't have at least 1 ILS, but perhaps in other regions
that's sometimes the case?

-cwk.

"Mike Rapoport" wrote
It isn't cheaper when you consider that it requires an operator.

It doesn't require a DEDICATED operator. There is no reason that the
squawk code could not be issued by the approach/center controller.
Typically, a non-busy airport would have no tower or a VFR tower, so
one-in, one-out. The code could be set by a remote landline from
approach/center, or it could simply use a fixed discrete code that
would not be used for other purposes in that sector.

Michael

Could be, would be, should be...whatever the case, the SZT airport was going
to have to hire a DEDICATED operator. Most uncontrolled fields around here
don't even have a RCO. In theory, I'm sure that you are right.

Mike
MU-2


"Michael" wrote in message
om...
"Mike Rapoport" wrote
It isn't cheaper when you consider that it requires an operator.

It doesn't require a DEDICATED operator. There is no reason that the
squawk code could not be issued by the approach/center controller.
Typically, a non-busy airport would have no tower or a VFR tower, so
one-in, one-out. The code could be set by a remote landline from
approach/center, or it could simply use a fixed discrete code that
would not be used for other purposes in that sector.

Michael

C Kingsbury wrote:

Out East I can't think of any Class D
fields that don't have at least 1 ILS, but perhaps in other regions
that's sometimes the case?

Sniff Now you've made me feel badly about my home class D airport in
Northern New Jersey, CDW, that has no precision approach (but we do have a
localizer).

I'd feel really badly did I not know that Hartford, in CT, also lacks a
precision approach. They don't even have a localizer; just an LDA.

[I think that this LDA lets you off pointing not at the airport, but at a
now closed airport across a river. But I may be recalling incorrectly.]

- Andrew

In article ne.com,
Andrew Gideon wrote:

C Kingsbury wrote:

Out East I can't think of any Class D
fields that don't have at least 1 ILS, but perhaps in other regions
that's sometimes the case?

Sniff Now you've made me feel badly about my home class D airport in
Northern New Jersey, CDW, that has no precision approach (but we do have a
localizer).

I'd feel really badly did I not know that Hartford, in CT, also lacks a
precision approach. They don't even have a localizer; just an LDA.

[I think that this LDA lets you off pointing not at the airport, but at a
now closed airport across a river. But I may be recalling incorrectly.]

- Andrew

In addition to Hartford and Caldwell, there's also Danburry which only
has a localizer.

"Mike Rapoport" wrote
Could be, would be, should be...whatever the case, the SZT airport was going
to have to hire a DEDICATED operator. Most uncontrolled fields around here
don't even have a RCO. In theory, I'm sure that you are right.

The difference between theory and practice is much greater in practice
than it is in theory.

The real issue is that what started as a good idea had to get by the
FAA.

Michael

"Michael" wrote in message
om...
"Mike Rapoport" wrote
Could be, would be, should be...whatever the case, the SZT airport was
going
to have to hire a DEDICATED operator. Most uncontrolled fields around
here
don't even have a RCO. In theory, I'm sure that you are right.

The difference between theory and practice is much greater in practice
than it is in theory.

The real issue is that what started as a good idea had to get by the
FAA.


Exactly.

Mike
MU-2

Michael