On Nov 1, 12:01*pm, Mike Schumann
wrote:
On 11/1/2010 12:59 PM, Eric Greenwell wrote:
On 11/1/2010 6:50 AM, bildan wrote:
From "AVweb":
[snip]
For situational awareness in a VFR environment, the bigger Nextgen
issues are completely irrelevant. *What is important is that we can see
other aircraft and they, and ATC, can see us. *That part of ADS-B works..
* The challenge is to get the price down so that people will actually
buy it before they are forced to in 2020 or beyond.

"That part of ADS-B works?"... What "part" of the things you were
talking about works and do you mean like they works now? And where? Or
are you talking about works in concept.

The FAA surveillance service part of the ADS-B deployment is being
rolled out. Besides Philly terminal services (and GOMEX?). I know
Florida has ADS-B terminal services coverage but it that essential
service and critical services within those terminals? And the enroute
segment has critical and essential as well? Knowing where there there
is FAA ATC surveillance coverage today via ADS-B is pretty important
qualifier in the claim "..and ATC, can see us...That part of ADS-B
works.". I believe the FAA claims those terminal and enroute
deployments for critical services will be complete in 2013. But the
details/progress on the FAA "critical services" surveillance
integration in the ADS-B technology works is exactly one of the
concerns in the IG report. e.g. see the section "Integrating ADS-B
with FAA’s Existing Automation Systems for Controllers Could Delay Its
Implementation" in the report.

And the "we can see other aircraft" part only works if the other
aircraft is properly equipped and that is hampered by all the other
adoption problems, costs, STC/TSO etc. that slow adoption in the GA
fleet, enough so that you don't have Metcalf's law working in your
favor to help build adoption.

Like above for ADS-B survelience.. where are the FAA critical service
actually deployed now so that ADS-R services are available so a UAT
equipped aircraft can see a 1090ES equipped aircraft? That's another
"critical service" so not in today's en-route essential service
rollouts. OK so for now the best we have in those regions is TIS-B,
which SSR terminal radars pump out data to TIS-B today?

The issues around the dual-link layers in the USA that mean at low
altitudes (like in the traffic pattern of many GA airports) and in
other areas an UAT and 1090ES equipped aircraft can't see each other
even if fully equipped with data-in and out devices. That is one of
the issues that make ADS-B data-in adoption problematic in GA aircraft
and something that has worried AOPA and others. So I would not claim
that part of ADS-B "works" either--not without lots of caveats.

I recommend anybody interested to read the report itself at
http://www.oig.dot.gov/library-item/5415 and make your own
conclusions.

Darryl