Outstanding Weather Needs and Priorities for Trajectory-Based Air Traffic Operations

The Federal Aviation Administration (FAA) is focused on evolving the National Airspace System (NAS) towards a Trajectory-Based Operation (TBO). TBO is an air traffic management concept centered on (a) the abilities of aircraft to fly precise paths in time and space and (b) the ability to strategically optimize and manage aircraft trajectories comprising the system operation. Key attributes of TBO are that every participant and air traffic system is operating to a common plan, and that plan is expressed and shared through “agreed trajectories,” which are flight- and flow-specific reference points with estimates for arrival times at key points along the flight path. The time-based parameters of TBO provide a common planning reference across all phases of flight, including pre-departure. Collectively, TBO is envisioned as a highly-choreographed, yet more dynamically-adjustable, gate-to-gate operation for pertinent NAS traffic (compared to today’s more static and distance-based management of the NAS). The fully developed TBO concept (and its support automation, capabilities, and procedures) will not be fully implemented until 2025 and later, but some incremental and contributing elements already exist or are under development and being tested for operational use.

The TBO concept, as defined, will be susceptible to a wide range of weather impacts, including hazards associated with multiple weather phenomena (convective and non-convective) that can affect and disrupt all phases of flight operations (surface, climb/descend, and cruise). The TBO concept includes procedures, automation, and distributed decision processes that may mitigate some of these disruptions. However, the complex and highly-coupled (in time and space) nature of TBO may render it ‘brittle’ during various weather conditions, reducing anticipated benefits.

The FAA’s NextGen Weather Processor (NWP) and Common Support Services – Weather (CSS-Wx) programs will be providing weather products, decision support, and dissemination services expected to mitigate weather impacts in the NAS, as it evolves from its current state towards TBO. Recently completed NWP and CSS-Wx Work Package 1 (WP1) shortfall analyses have identified remaining gaps and associated mitigations specific to TBO that may be targeted for WP2 enhancements of those same two systems.

This paper will present results from the weather shortfalls assessments, will specifically identify the primary weather support needs for TBO, and will lay out the operational gaps in TBO-based air traffic management that cannot be effectively addressed without key, specific advancements from the weather research community.