WAAS

Last issue of AW&ST has article stating "Following a three-year delay
to correct software problems, the FAA has commissioned the Wide Area
Augmentation System (WAAS) to refine GPS guidance for en route and
approaches"..........................

"It will take years for the FAA to design and certify approaches to
runways at the current rate of about 300 per year." ..................

"by using WAAS and GPS as the sole means of navigation, aircraft can
operate lower and still be safely above terrain and
obstacles."........

"Dan Hanlon, FAA's WAAS program manager, emphasized that the two key
benefits that WAAS has over GPS are vertical guidance and improved
availability of signals"..............

"the FAA has spent $886 million on WAAS to date" ....................

So now you know )

Big John.

On Thu, 17 Jul 2003 14:32:39 -0500, Big John
wrote in Message-Id: :

Last issue of AW&ST has article stating "Following a three-year delay
to correct software problems, the FAA has commissioned the Wide Area
Augmentation System (WAAS) to refine GPS guidance for en route and
approaches"..........................

"It will take years for the FAA to design and certify approaches to
runways at the current rate of about 300 per year." ..................

"by using WAAS and GPS as the sole means of navigation, aircraft can
operate lower and still be safely above terrain and
obstacles."........

"Dan Hanlon, FAA's WAAS program manager, emphasized that the two key
benefits that WAAS has over GPS are vertical guidance and improved
availability of signals"..............

"the FAA has spent $886 million on WAAS to date" ....................

So now you know )

Big John.


Here's a little more information from GPS mailing list:


Return-path:
Date: Thu, 10 Jul 2003 10:45:52 -0400 (EDT)
From: Bob Siegfried
Subject: WAAS
To:
Reply-to: GPS for Aviation
Message-id:

In a message dated 7/10/03 8:52:24 AM Central Daylight Time,
writes:

The FAA flicked the switch on the Wide Area Augmentation System (WAAS)
signal, a crucial first step on the way to highly accurate satellite-based
navigation in the U.S. "We're just waiting for the avionics to catch up," said FAA
spokesman Greg Martin.

Good Morning George,

That is good news, but it is tempered by the way the data is being
implemented.

The FAA is currently enamored with building ILS look alike approaches
using WAAS.

That sounds good. The trouble is that an "ILS Look Alike Approach"
via WAAS only provides the airborne guidance. Without a suitable
obstacle environment and approach lighting, the guidance can actually
be detrimental to GA operations.

How so? If the obstacle environment is such that a DH of five or six
hundred feet results, there will be a a visibility minima that will
allow visual sighting of the runway when the aircraft is at the DH.
That can mean that a 600 foot DH will require over two miles
visibility.

That doesn't sound all that bad, except that a non precision approach
to the same runway will likely have a minimum required visibility of
one mile.

To the FAA's credit, they are generally providing an LNAV approach
along with the VNAV that does take advantage of the lower visibility
requirement.

The rub comes with the circling minima.

The FAA has a policy that when there are two approaches on the same
approach plate, the circling minima can be no lower than the highest
required visibility for any approach shown on that approach plate.

That means that an approach which would otherwise have circling
minimums of 600 and one will be stuck with a circling minima of six
hundred and two merely because there is a VNAV approach designated for
that runway.

I could provide many examples where we are losing considerable
operational capability due to this anomaly. Unfortunately, I have to
run and can't spend the time right now, but if anyone is interested, I
do have some horrible examples in my files. (If I can find them that
is!)

It is shame that implementation of the WAAS is causing our minimums to
go up.

The worst thing is that nobody seems to care!

Happy Skies,

Old Bob

Big John wrote:

"the FAA has spent $886 million on WAAS to date" ....................

Gaaah! And the way they're planning things, I'm sure
lower mins won't be available until the airport sinks
a million or so into an approach lighting system of sorts.

Help me out here, fellow campers. IIRC I read a Wally
Roberts interview on AVWEB which referred to the cost of
an ILS (minus approach lights) as being about $1.5 million
dollars. And it's fair to consider "minus approach lights"
because the airport will need to come up with an ALS etc
even w/ WAAS.

So....how many airports are there in the country?

Looks to me as though the FAA could have installed ILS
at about 500 GA airports for the cost of WAAS, and
people would be flying 'em today

Wonder how that compares to the number of US airports
where other factors (obstructions, terrain, rwy
length etc) are otherwise compatible w/ a precision-
type approach.

Oy. Your tax dollars at work.

Cheers,
Sydney

One of the advantages of WAAS is that it can provide approaches with
vertical guidance to minimums that are better than non-precision approaches
but worse that an ILS *without* the full ALS, etc. At my home airport that
could often make the difference between missing the NDB approach and going
to the nearest airport with an ILS or landing and driving my own car home.
The idea being you can get a whole lot more utility for no additional costs
for ground-based infrastructure.

Dave Reinhart


Sydney Hoeltzli wrote:

Big John wrote:

"the FAA has spent $886 million on WAAS to date" ....................

Gaaah! And the way they're planning things, I'm sure
lower mins won't be available until the airport sinks
a million or so into an approach lighting system of sorts.

Help me out here, fellow campers. IIRC I read a Wally
Roberts interview on AVWEB which referred to the cost of
an ILS (minus approach lights) as being about $1.5 million
dollars. And it's fair to consider "minus approach lights"
because the airport will need to come up with an ALS etc
even w/ WAAS.

So....how many airports are there in the country?

Looks to me as though the FAA could have installed ILS
at about 500 GA airports for the cost of WAAS, and
people would be flying 'em today

Wonder how that compares to the number of US airports
where other factors (obstructions, terrain, rwy
length etc) are otherwise compatible w/ a precision-
type approach.

Oy. Your tax dollars at work.

Cheers,
Sydney

In a previous article, Sydney Hoeltzli said:
So....how many airports are there in the country?

There are 5026 public airports and 8906 private airports in the FAA
database. Also 10 private and 1 public balloonport, 25 private and 4
public gliderport, 5261 private and 78 public heliports, 282 private and
201 public seaplane bases, 85 private and 3 public STOLports, and 129
private and 6 public ultralight fields.


--
Paul Tomblin , not speaking for anybody
SCSI is *NOT* magic. There are *fundamental technical reasons* why it is
necessary to sacrifice a young goat to your SCSI chain now and then.

In article , Sydney Hoeltzli
wrote:

Looks to me as though the FAA could have installed ILS
at about 500 GA airports for the cost of WAAS, and
people would be flying 'em today

There are 40 ILS frequencies. Thus, frequency management
is a "challenge."

There are very tough siting criteria for installation
of ILS, especially the GS. Some airports that could
get WAAS or LAAS approaches can't have ILS.

--
Bob Noel

David Reinhart wrote:
One of the advantages of WAAS is that it can provide approaches with
vertical guidance to minimums that are better than non-precision approaches
but worse that an ILS *without* the full ALS, etc. At my home airport that
could often make the difference between missing the NDB approach and going
to the nearest airport with an ILS or landing and driving my own car home.

Well, it depends upon the airport of course, but around here the
above frequently describes what you get w/ a non-precision GPS approach.
For example UNO (West Plains MO), the VOR 36 will get you to 672 agl;
the GPS 36 will get you to 372 agl (what a GPS approach with a clean
obstruction path can do for ya; in the other direction it's only 412).

The idea being you can get a whole lot more utility for no additional costs
for ground-based infrastructure.

What minimums would an ILS with no ALS get you? a WAAS approach?
Even if it's down to 200 AGL, is 172 ft worth $886 million? Holy
cow, and I'm a big fan of GPS approaches!

Cheers,
Sydney

On Tue, 22 Jul 2003 00:44:30 GMT, Sydney Hoeltzli
wrote:

Paul Tomblin wrote:

There are 5026 public airports

Thanks Paul!

Any way to tell how many of 'em already have ILS?

In theory, I suppose the $886 million which could have
put ILS at another 10% of the public airports, will
enable nice low approach minimums at many more.

But I'm wondering how many of those other airports just
won't meet the TERPS criteria for a lower approach,
and won't gain much from WAAS.

Maybe I'm being too negative here, I dunno.

Cheers,
Sydney

I have a flying buddy who has reason to be informed about big vacuum
tubes. The other day, we were talking about LORAN and he told me the
feds had already stopped ordering new tubes and were working through
their spares. We didn't talk about VHF, so I don't know if anything
similar is true for VOR/ILS, but I imagine the same philosophy holds.

It makes sense. I was talking to another buddy who sells obsolete
MIL-SPEC ICs for old but still-in-use military systems. He reckons
the current premium on these parts is around a thousand percent, and
will only go higher until the systems are replaced with newer ones
that use commercial off-the-shelf (COTS) parts or the stock of old ICs
is exhausted.

So using the WAAS money for new ILSs would probably have been a
short-sighted economy.

I dunno if that makes you feel any better.

Don

KHYX already has an NDB, and a GPS approach, and a VOR-A off of KMBS 13
miles away... And now, drum roll we are getting an ILS... Uncle Sugar is
sweet...

Denny

"Sydney Hoeltzli" wrote in message
...
David Reinhart wrote:
One of the advantages of WAAS is that it can provide approaches with
vertical guidance to minimums that are better than non-precision
approaches
but worse that an ILS *without* the full ALS, etc. At my home airport
that
could often make the difference between missing the NDB approach and
going
to the nearest airport with an ILS or landing and driving my own car
home.

Well, it depends upon the airport of course, but around here the
above frequently describes what you get w/ a non-precision GPS approach.
For example UNO (West Plains MO), the VOR 36 will get you to 672 agl;
the GPS 36 will get you to 372 agl (what a GPS approach with a clean
obstruction path can do for ya; in the other direction it's only 412).

The idea being you can get a whole lot more utility for no additional
costs
for ground-based infrastructure.

What minimums would an ILS with no ALS get you? a WAAS approach?
Even if it's down to 200 AGL, is 172 ft worth $886 million? Holy
cow, and I'm a big fan of GPS approaches!

Cheers,
Sydney