human factors

Weather Information Presentation 25-7
do so in a tactical way, using a see-and-avoid concept or airborne weather radar. Automatic weather
updates are not routinely provided to the pilot. Controllers maintain an overall awareness of hazardous
weather conditions that might impact their area of responsibility, but are not required to separate the
aircraft from the weather. The strategic planning of routes owing to weather does occur, but often, it is
based on an incomplete picture of the weather state. As a result, traffic is usually organized in an “intrail”
structure, requiring aircraft to fly at less-than-optimal altitudes, speeds, and routings.
NAS modernization may result in the introduction of automated functions that can transition the
controller from tactical control to strategic traffic management. The pilot can be transformed into a
systems monitor who will no longer personally interact with the air-traffic control. These things will,
of course, occur in carefully orchestrated stages over many years, and the aviation weather system must
match the needs of each stage. A vision of the NAS of the future shows the aircraft separation being
maintained by satellite communications; computer routing of aircraft to permit direct and optimal
routings; extensive use of satellite and data-link communications for flight management and weather
information; highly interactive and graphic displays for process management; and, overall, strategic
planning being the rule instead of the exception. Furthermore, with the evolution of NAS, the preciseness
and informational content of the aviation weather supporting it should also evolve.
The Aviation Digital Data Service (ADDS), now approved for operational use by the FAA and NWS,
is a means to take advantage of the temporal and spatial improvements and the gridded four-dimensional
nature of today’s weather data. The ADDS is a highly user-interactive graphical tool available
to all classes of users (described later), allowing the visualization of flight profile-specific aviation weather
hazards—turbulence, icing, convection—as well as winds and temperature. The user can also overlay or
request “legacy” NWS products including the graphical depictions of hazard information and textual
products. This service is available 24 h a day, 7 days a week, at http://adds.aviationweather.gov.
Soon to come are the probabilistic forecasts of turbulence, convection, and inflight icing that will be
integrated into the future decision-support tools for air-traffic management. Figure 25.1 is an example
of an inflight icing depiction extracted from the ADDS Web site that shows the hazard levels up to
18,000 ft, similar to the textual description presented earlier, only on a national scale and much easier
to understand. The user can “zoom” as needed and create cross sections along a planned route of flight
at a particular altitude.
25.4.2 Users of Aviation Weather
The aviation weather users of today will change as the NAS changes, but generally, the functions
performed will remain intact, possibly performed by computer or defined by other roles in the system.
Therefore, it is very important to assume a task or functional orientation when allocating weather
information needs. The following discussion of aviation weather users is by no means exhaustive, but
conceptually illustrates the broad spectrum of user needs that are being addressed.
Airline and military users cover the type-of-user spectrum, from meteorologist to end user or pilot.
Similarly, weather information needs span the spectrum from raw data to decision aids, and a careful
consideration of these needs can literally make the difference between high payoff or miserable failure
of the informational impact on operations.
Functions within the broad area of air-traffic control also require diverse approaches to defining the
needs. Floor controllers within ARTCC sectors and Terminal/Radar Approach Control (TRACON),
for example, are concerned with tactical control and separation of traffic in smaller geographical areas.
Relative to weather, this function is perhaps limited by today’s incomplete and imprecise weather information
picture—that is, better information and presentation might expand the strategic planning role
of these users. The ARTCC Traffic Management Unit (TMU) and Air-Traffic Control System Command
Center (ATCSCC), on the other hand, are primarily concerned with strategic planning and traffic
flow management at a national level. Weather information needs tend to be at a top-level for the most
part, but also needs to include detailed and precise descriptions of weather conditions at key or pacing