Distributed Air/Ground Traffic Management
(DAG-TM) is an integrated gate-to-gate operational
concept in which flight deck crews, air traffic service
providers, and aeronautical operational control
(AOC) personnel use distributed decision-making to
enable user preferences and increase system capacity,
while meeting air traffic management requirements
(figure 1). The DAG-TM operational concept
was developed by NASA (Ames, Langley and Glenn
Research Centers) under the Advanced Air Transportation
Technologies (AATT) Project, as a detailed
instantiation of possible operational modes for Free
Flight. It embodies the far-term vision of the AATT
Project regarding air traffic operations in the National
Airspace System (NAS).
DAG-TM operations will be accomplished with a
human-centered operational paradigm enabled by
procedural and technological innovations. All user
classes (commercial carriers, general aviation, etc.)
will be addressed by DAG-TM, with emphasis
directed toward ensuring access to airspace resources
for the entire user community. Although all users
would benefit from DAG-TM, users with higher levels
of equipage would benefit even more. Figure 2
depicts some of the airspace problems that arise from
dynamic constraints in the NAS; the DAG-TM
solutions to these (and other) problems are called
concept elements. The DAG-TM operational concept
was formulated as a cohesive set of 15 concept
elements designed to safely mitigate the extent and
effect of dynamic NAS constraints, while maximizing
the flexibility of airspace operations. From these 15
concept elements, 4 were selected for initial studies
under the AATT Project. They are (1) En Route
Airspace: Collaboration for mitigating local Traffic
Flow Management (TFM) constraints; (2) En Route
Airspace: Free maneuvering for user-preferred
separation and local TFM conformance; (3) En Route
Airspace: Trajectory negotiation for user-preferred
separation and local TFM conformance; and (4)
Terminal Airspace: Self-spacing for merging and
in-trail separation of arrivals.
It is noted that Free Maneuvering and Trajectory
Negotiation are complementary concept elements
that address the problem of inefficient trajectory
deviations for separation and local TFM
conformance.
Ongoing research activities under each concept
element include concept development, research
prototype development, concept validation, cost/benefits
assessments, and safety assessments.
Point of Contact: K. Bilimoria/S. Green
(650) 604-1638/5431
kbilimoria@mail.arc.nasa.gov
sgreen@mail.arc.nasa.gov
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