Unmanned Aerial Systems - Integrating UAS into National Airspace System

The Federal Aviation Administration (FAA) has been very careful about setting the legislation for commercial use of unmanned aerial system (UAS) for a long time, despite the fact that many other countries have already established their regulations to allow UAS operations (GAO, 2015, p.29). The main reason is that of all the safety issues concerning the operation of UAS, the ability to safely maintain proper separation from other traffic in the National Airspace System (NAS) is the most difficult to overcome (DOT, 2013). To FAA, any unmanned aerial vehicle (UAV) has to be able to demonstrate a high level of robustness in terms of its ability to “sense and avoid” other air traffic. As required by Section 332(a) of the FAA Modernization and Reform Act, US. Department of Transportation has released a UAS comprehensive plan to ensure that all commercial airborne UAS are equipment with “Sense and avoid” capabilities (FAA, 2013). “Sense and Avoid” is necessary to achieve autonomy (Yu & Zhang, 2015) and can be achieved via two methods, airborne sensing and ground sensing (Zeitlin, 2010). Airborne sensing will make use of sensors on board the UAV to detect and avoid obstacles, whereas ground sensing makes use of ground radar and other sensors to relay air traffic to the UAV for it to maintain separation from other air traffic. However, airborne sensing requires expensive on-board sensors which can be heavy and consume significant energy. Ground sensing on the other hand, has to be present in the entire operating area of the UAV, making it impractical for long distance flights. 

According to Fasano et al. (2015), the two functions to have separation assurance and to be able to make extreme manoeuvres are key to good “sense and avoid”. Having airborne surveillance for separation assurance and collision avoidance is the ultimate goal of a UAS system and can be achieved using cooperative instruments such as transponders to broadcast and interrogate, and non-cooperative sensors such as Traffic Collision and Avoidance System (TCAS), which has an advantage in case of an air-to-air radio link loss. FAA (2016) states that there are three types of UAS operations: public; civil; and model aircraft. For civil use, special airworthiness certificate can be applied under experimental category; type and airworthiness certificate under Restricted category; and certificate of wavier or authorization under commercial category (FAA, 2016).

Accelerating the use of UAS in commercial applications will provide economic and social benefits. The future of UAS integration into NAS depends upon the pace of FAA development of a comprehensive regulatory framework, which has some urgent need to catch up with the fast developing UAS technologies.

Reference

DOT (2013). Unmanned Aircraft System (UAS) Service Demand 2015-2035: Literature Review & Projections of Future Usage. Retrieved from https://fas.org/irp/program/collect/service.pdf

Fasano, G., Accardo, D., Tirri, A. E., Moccia, A., & De Lellis, E. (2015). Radar/electro-optical data fusion for non-cooperative UAS sense and avoid. Aerospace Science and Technology, doi:10.1016/j.ast.2015.08.010

FAA (2013). UAS comprehensive plan: A report and the Nation’s UAS path forward. Retrieved from http://www.faa.gov/about/office_org/headquarters_offices/agi/reports/media/UAS_Comprehensive_Plan.pdf

FAA (2016). Unmanned aircraft systems: Frequently asked questions. Retrieved March 30, 2016 from https://www.faa.gov/uas/faq/#qn4

GAO (2015). Unmanned aerial systems: FAA continues progress toward integration into the National airspace. Retrieved from https://fas.org/irp/program/collect/gao-15-610.pdf

Yu, X., & Zhang, Y. (2015). Sense and avoid technologies with applications to unmanned aircraft systems: Review and prospects. Progress in Aerospace Sciences, 74, 152-166. doi:10.1016/j.paerosci.2015.01.001

Zeitlin, A. D. (2010). Sense & avoid capability development challenges. IEEE Aerospace and Electronic Systems Magazine, 25(10), 27-32. doi:10.1109/MAES.2010.5631723