REDUCING EN ROUTE CONGESTION

In addition to the congestion experienced at major hubs and terminal areas, certain parts of the en route structure have reached capacity. Easing the burden on high-volume airways and eliminating airborne choke points are some of the challenges addressed by new airspace plans.

MATCHING AIRSPACE DESIGN TO DEMANDS

More new RNAV routes are being created, which are essentially airways that use RNAV for guidance instead of VORs. They are straighter than the old VOR airways, so they save flight time and fuel costs. By creating additional routes, they reduce traffic on existing airways, adding en route capacity. As new routes are created near existing airways, chart clutter will become more of an issue. Electronic chart presentations are being developed that will allow pilots to suppress information that is irrelevant to their flight, while ensuring that all information necessary for safety is displayed. The high degree of accuracy and reliability of RNP procedures offers another means of increasing capacity along popular RNAV routes. Instead of having all the aircraft that are using the route fly along the same ground track, RNP allows several closely spaced parallel tracks to be created for the same route. In essence, this changes a one-lane road into a multi-lane highway. [Figure 6-8]

REDUCING VOICE COMMUNICATION

Many runway incursions and airborne clearance mistakes are due to misunderstood voice communications. During busy periods, the necessity of exchanging dozens of detailed instructions and reports leads pilots and controllers to shorten and abbreviate standard phraseology, often leading to errors. It stands to reason that better ways to transfer information could reduce voice communications, and thus reduce the incidence of communication errors. One such innovation is similar to the display screen at fast-food drive-up windows. As the cashier punches in the order, it is displayed on the monitor so the customer can verify the order. This kind of feedback reduces the common problem of hearing what is expected to be heard, which is particularly problematic in ATC clearances and read backs. Not only does reducing voice communications reduce frequency congestion, it also eliminates certain opportunities for misunderstanding.

Controller pilot data link communication (CPDLC) augments voice communications by providing a second communication channel for use by the pilot and controller, using data messages that are displayed in the cockpit. This reduces delays resulting from congestion on voice channels. The initial version of CPDLC will display a limited number of air traffic messages, but future versions will have expanded message capabilities and permit pilot-initiated requests.