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by the Joint Planning and Development
Office, which facilitates inter-agency
cooperation.
Without NextGen, the FAA estimates
that gridlock in the skies will cost the US
economy US$ 22 billion a year by 2022,
growing to more than US$ 40 billion by
2033 if the air transportation system is not
transformed.
In the NextGen system, most communication
will be through digital data, much
of it transferred directly from computer to
computer. Navigation and surveillance will
be primarily satellite-based, allowing for
more precise flight paths than currently
possible with the existing ground-based
infrastructure, and better situational
awareness of all aircraft for both controllers
and equipped pilots. The airspace will
be managed dynamically, with air traffic
control services not tied to a geographic
location. As in the SESAR environment,
NextGen will facilitate the sharing of relevant
information between system users
through network-enabled information
access.
By 2018, the FAA expects to have a midterm
NextGen in place.
So although there are many areas of
commonality between the European
and US systems, and both claim to be
in line with the International Civil Aviation
Organization抯 (ICAO) Operational
Concept, there are clear differences
when it comes to deployment and
implementation.
揘extGen and SESAR
represent two different
philosophies on how to
achieve essentially
the same goal,?
said David McMillan,
Director General of
EUROCONTROL.
The US, for example, is anxious to get
Automatic Dependent Surveillance ?
Broadcast (ADS-B) up and running
because it is a surveillance tool that can
provide significant safety and efficiency
benefits in the US National Airspace
System (NAS). Victoria Cox, Senior Vice
President of NextGen and Operations
Planning with the FAA, pointed out that
ADS-B implementation in Alaska had led
to a 47% decrease in air accidents there.
Europe conversely boasts perhaps the
most comprehensive radar coverage of
any region on earth, so surveillance is less
of an issue than communications. In terms
of mandating Europe has been pushing
for controller pilot data link communications
(CPDLC) while the US has given
priority to ADS-B.
揝ome areas concern us more, others
concern Europe more,?said Cox. 揊or
example, weather causes 70% of our
delay in the US, so we focus more on
this aspect than Europe. And we want to
take immediate advantage of ADS-B. Our
challenge is mainly traffic levels: Europe抯
is predominantly the number of political
entities that are involved in the decisionmaking
process and the fragmentation of
the airspace system.?
揥e have different approaches to so
many elements,?agreed Bo Redeborn,
EUROCONTROL抯 Director of ATM
Strategies. 揟his is primarily because we
have different priorities.?
Redeborn argues: 揥e need to identify
the applications we are aiming to achieve
independent of the physical layer that
supports them. The key is to agree the
applications. Then we can look for the
most suitable link for a specific purpose,
and it may be that a multi-mode receiver
is the solution in some instances. That
way, we can run the same application over
more than one link. This approach would
also facilitate the eventual transition to the
future communication infrastructure.?
McMillan stresses that the first step
towards ensuring interoperability is 搈ore
than intermittent exchanges?between
the SESAR and NextGen teams. 揥e
need something that approximates a
programme board to make sure the two
programmes are not diverging,?he said.
At a recent ICAO Forum in Montreal,
agreement was reached on initiating a
In the US, meanwhile, NextGen is described as a 搘ide ranging
transformation of the entire national air transportation system (?
to meet future demands and avoid gridlock,?both in the sky and
at the nation抯 airports. It will use 21st century technologies (technologies
and activities that support this transformation are currently
part of the FAA抯 investment portfolio and represent a step beyond
legacy modernisation programmes) to ensure that future safety,
capacity and environmental needs are met. Like SESAR, it moves
away from conventional ground-based infrastructure to new and
more dynamic satellite-based systems.
8
Skyway 49 - Autumn 2008 21
process for sharing developments in the
SESAR and NextGen systems, identifying
both commonalities and differences
　
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本文鏈接地址：Skyway Magazine Autumn 2008(14)