“Safety is the FAA’s most important responsibility in the pursuit of integrating commercial UAS into the national airspace” (Cho, 2014). By 2025, the FAA plans to overhaul the National Airspace System (NAS), creating the Next Generation Air Transportation System (NextGen). NextGen will utilize satellite based information to create a safer, more convenient, and dependable airspace system that can integrate UAS routinely (Kenny, 2013).
UAS integration into the NAS requires advances in automation, communication, more precise airspace information provided by ADS-B, and procedures, like delegated separation, which is employed with manned aircraft (Kenny, 2013). “Delegated separation is an air traffic management capability in which responsibility for separation from one or more aircraft is assigned to the crew, operator or pilot, by an air traffic controller, in specific tactical situations, to improve operational efficiency in the NAS” (Domino, Tuomey, Mundra, Smith, 2010). However, since there is no human onboard a UAS to take responsibility for locating and monitoring traffic by looking out the window, for example, a UAS will utilize sensor suites and other sense and avoid technology built in to the UAS that will ensure a UAS can autonomously evade potential conflicts. Because UAS operators will have to rely on their ground control station (GCS) capabilities for GPS location and even traffic alerts on a cockpit situation display (CSD). GCS, like the MUSIM and CSD, like the Ames 3D display, give operators a robust display interface that includes conflict detection alerts to help maintain separation with other aircraft in the NAS (Kenny, 2013).
The potential for lost communication links between UAS and a GCS presents many problems. Normally, when communication is lost, a UAS “flies a pre-programmed contingency route based on its current state of flight altitude, orientation, [and] bearing” (Van Cleave, 2011). However, in the NAS, air traffic controllers would find it difficult to impossible to ascertain the rogue UAS’ course to clear or alert the appropriate traffic and ensure the safety of others. To counter these scenarios, MITRE has developed software called The Intelligent Analyzer. The Intelligent Analyzer “monitors the UAS’s flight management system and constantly queries its current position, altitude, true airspeed, next waypoint, and remaining fuel mileage” (Van Cleave, 2011) throughout a flight. In the event of a loss of communication, a synthesized voice message will broadcast over existing radio communications links alerting ATC and other traffic in the area.
The size and airframe technology and status of UAS must be considered in the NAS in the same way it is for manned craft, especially in terms of airspeed or landing or take off priority. However, arguments have been made that manned aircraft should always have priority over unmanned aircraft. The Experimental Aircraft Association has released statements saying that “the entrance of UAS into the national airspace system cannot come to the detriment of manned aircraft operation” (General Aviation, 2015). The size of UAS and manned aircraft in the airspace could have a temporary effect on the airspace including wake turbulence. Small manned aircraft following large UAS and small UAS following large manned aircraft must consider these effects. CDS and GCS using advanced, NextGen, GPS display technology, should also allow pilots, operators and ATC the ability to be able to easily ascertain the speed, type and perhaps size of the air traffic around them.
In conclusion, the separation of UAS in the NAS can be promoted through advances in autonomy, sense and avoid technology, GCS and CDS displays with conflict warning, and software that reacts to loss of communication by sending out verbal warnings on relevant frequencies. Parallel with the FAA’s NextGen NAS plans, these advances will allow for a more seamless integration of UAS into the NAS.
References:
Cho, Y. (2014). Lost in debate: The safety of domestic unmanned aircraft systems.Journal of
Strategic Security, 7(4), 38-56. doi:http://dx.doi.org.ezproxy.libproxy.db.erau.edu/10.5038/1944-0472.7.4.4
Domino, D.A.; Tuomey, D.; Mundra, A.; Smith, A., "Air ground collaboration through delegated
separation: Application for departures and arrivals," in Integrated Communications Navigation and Surveillance Conference (ICNS), 2010 , vol., no., pp.G5-1-G5-17, 11-13 May 2010 doi: 10.1109/ICNSURV.2010.5503250 from http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5503250&isnumber=5503230
General Aviation (2015, November 05). EAA: Manned aircraft must have priority over drones.
Retrieved February 06, 2016, from http://generalaviationnews.com/2015/11/05/eaa- manned-aircraft-must-have-priority-over-drones/
Kenny, C., "Unmanned Aircraft System (UAS) Delegation of Separation in NextGen Airspace"
(2013). Master's Theses. Paper 4284 from http://scholarworks.sjsu.edu/cgi/viewcontent.cgi?article=7831&context=etd_theses
Van Cleave, D. (2011, January). Keeping Track of Unmanned Aircraft by Overcoming "Lost
Links" Retrieved February 06, 2016, from http://www.mitre.org/publications/project- stories/keeping-track-of-unmanned-aircraft-by-overcoming-lost-links