Concept Definition for
Distributed Air/Ground
Traffic Management (DAG-TM)

Version 1.0

Advanced Air Transportation Technologies (AATT) Project
Aviation System Capacity (ASC) Program
National Aeronautics and Space Administration

September 30, 1999

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EXECUTIVE SUMMARY

The Distributed Air/Ground Traffic Management (DAG-TM) concept is a coherent set of conceptual elements that describe possible modes of operation within the outlines of the Free Flight concept defined by the RTCA Task Force 3 in Ref. 1. It may be viewed as one possible approach to the potential implementation of Free Flight, progressing along the path started by the Free Flight Phase 1 activities. This DAG-TM concept was developed by the Advanced Air Transportation Technologies (AATT) Project.

Background
The AATT Project is part of NASA’s Aviation System Capacity (ASC) Program. AATT’s objective is to improve the overall performance of the National Airspace System (NAS) as a whole. In order to meet this objective, AATT is developing decision support technologies and procedures to aid NAS stakeholders in the near-term, mid-term, and far-term. The vision of the AATT Project regarding far-term NAS operations is embodied in the DAG-TM concept definition presented in this document.
In order to develop this DAG-TM Concept Definition and a companion DAG-TM Research Plan (Ref. 2), the AATT Project created a DAG-TM Team, composed of personnel with expertise in various disciplines of Air Traffic Management.

DAG-TM Vision Statement
The fundamental characteristics of DAG-TM have been defined in the following vision statement developed by the DAG-TM Team.
“Distributed Air/Ground Traffic Management is a National Airspace System concept in which flight deck (FD) crews, air traffic service providers (ATSP) and aeronautical operational control (AOC) facilities use distributed decision-making to enable user preferences and increase system capacity, while meeting air traffic management requirements. DAG-TM will be accomplished with a human-centered operational paradigm enabled by procedural and technological innovations. These innovations include automation aids, information sharing and Communication, Navigation, and Surveillance (CNS) / Air Traffic Management (ATM) technologies.”

Scope of DAG-TM Concept
DAG-TM is a proposed concept for gate-to-gate NAS operations beyond the year 2015. It will address dynamic NAS constraints such as bad weather, Special Use Airspace (SUA) and arrival metering/spacing. The goal of DAG-TM is to enhance user flexibility/efficiency and increase system capacity, without adversely affecting system safety or restricting user accessibility to the NAS.
The DAG-TM concept is intended to address all user classes (commercial carriers, general aviation, etc.) with an emphasis towards ensuring access to airspace resources for the entire user community. It covers all flight phases (Pre-Flight Planning, Departure, Cruise and Arrival) and operational domains in the NAS (Surface, Terminal Airspace and En route Airspace). Although other operational domains (e.g., European, oceanic, and under-developed airspace) are outside the scope of the current DAG-TM concept, research activities will give due consideration to global interoperability issues.
　
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