Editor's Note: This is a guest post from Ashwin JadavGlobal aviation is steadily progressing through the modernization of technological infrastructure into the new era of seamless air transportation. A major component of this transformation is a complete overhaul of the air traffic control (ATC) system within developed nations, ultimately resulting in the transition to air traffic management (ATM).
In modern-day flight operations, flight planners and dispatchers file a route or flight plan (FPL) using existing navigational infrastructure. The flight then flies the assigned trajectory which includes airways, waypoints, VORs and other nav-aids (as mentioned in the FPL). In the event of traffic congestion, adverse weather or any emergency, air traffic control (ATC) may choose to modify the aircraft’s route, thereby altering the FPL. Conversely, using a bottom-up approach, flight dispatchers could select their trajectory initially based on these factors and then fly the trajectory once approved by ATC. The concept of Random Routing, although not a brand new one, has evolved into a much broader concept called Air Traffic Management (ATM). A Random Route by definition is a trajectory that is picked prior to a particular flight based on traffic patterns, upper winds, weather forecasts, etc. for that particular flight. The benefits of this approach, however, are maximized on long-haul flights.
The Atlantic Oceanic Random Routing RNAV Area (AORRA) is one of the largest expanses of airspace that permits flights to fly without restricted ground navigational aids within its boundaries. It is located between the American and the African continents mainly in the Southern hemisphere. Although a revolutionary means for seamless navigation, the AORRA has not been able to fully utilize the potential of long range aircraft and provide maximum benefits. There were just a few entry and exit points (nav aids / waypoints) on the AORRA boundary via which an aircraft can enter or exit the airspace. In order to completely randomize the trajectory within the AORRA, an increased number of entry/exit “gates” were needed.
*Note: Area Navigation (RNAV) can be defined as a method of navigation that permits aircraft operation on any desired course within the coverage of station-referenced navigation signals or within the limits of a self contained system capability, or a combination of these.Being two of the airlines that use the airspace most frequently, Delta Airlines and Emirates joined hands with the International Civil Aviation Organization (ICAO), the International Air Transportation Association (IATA) and the Civil Air Navigation Services Organization (CANSO) to initiate a pilot project. Delta’s focus was mainly on the Atlanta – Johannesburg long-haul route while Emirates concentrated on their Dubai – Sao Paulo route. The working group has successfully placed several waypoints on the AORRA boundary for flexible entry and exit. Further, resultant issues such as the intersection of the North American-African and Eurpoean-South American flight corridors were addressed. Since, giving flights additional flexibility would result in multiple possibilities of flight paths on these corridors intersecting, flight level rules were established. Due to the under-developed airspace structure of the African continent, the transition waypoints into/from the AORRA airspace were limited. The implementation of new airways connecting the domestic structure with the AORRA airspace was successfully completed in mid-2011. Finally, the working group presented a paper proposing the additional expansion of the AORRA boundary. The successful implementation of the proposal would bring the AORRA boundary closer to the African continent allowing aircraft to use existing ground infrastructure to aid navigation. The working paper presented at the South Atlantic Group meeting (SAT/16) can be found
here.
Not surprisingly, other major air traffic management projects such as the U.S. Next Gen and European SESAR use trajectory optimization and flight flexibility as their foundation. Adding additional flexibility to such airspaces and implementing Random Routing could result in massive time and fuel (thereby CO2) savings for long-haul flights within ‘low density and permitted’ airspaces.
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