Unmanned Aerial Vehicles (UAV) deliver sophisticated capabilities with tremendous cost advantage over traditional methods. While this technology has evolved from military missions, civil and commercial sectors are beginning to realize many of the same remote sensing benefits. However, one of the main barriers to rapid full-scale commercial growth is the concern for safety. As a myriad of certification agencies scramble to keep up with the unique demands of this fast-growing industry, one thing is clear – where applicable, pertinent certification standards for manned aircraft are starting to apply. For the complex electronics that provide the brains of these systems, this means a swift move towards compliance with DO-178C for software and DO-254 for hardware development.
UAV Evolution into the Civilian Domain
Not long ago, talk of UAV systems was reserved for the intelligence community. Today, the mainstream media is reporting on Amazon’s plans to use “drones” for 30 minute deliveries. It is clear that UAV systems have progressed rapidly in the past two decades. These sophisticated machines have branched out from their military roots to offer an endless array of commercial and civil possibilities, from border surveillance to fire control, police work, aerial mapping, and so on. An estimated $8 billion industry by 2018, huge potential lies ahead for these magnificent systems.
However, several key challenges stand in the way. First is the complex and uncertain certification landscape. Second is the necessary shift in both mindset and processes from the developers of these systems themselves.
The Certification Landscape
The UAV technology boom of the past two decades offered the military tremendous benefit in both budget and life savings. But in this world, accomplishing the “mission” is always the primary agenda. Safety, while a consideration, is a secondary objective as budget is available. Nonetheless, UAVs had to meet the pertinent military airworthiness guidance (e.g., MILHDBK 516B and MIL-STD-882E). However, as missions began morphing into possible civil applications, contracts started including requests for more robust compliance to civil airworthiness standards. Meanwhile, civil aviation agencies took notice of the Unmanned Aerial Systems (UAS) phenomena as well. What they noticed was that UAS (the term used by policy makers) include not only the vehicle itself, but also the control segment and data link – two very important differences from manned aircraft that complicate certification considerations.
A topic of discussion and concern for years, UAS certification policy has only recently gained significant momentum. At an international level, the ICAO (a special agency of the United Nations chartered with the safety of international aviation) published Circular 328 covering unmanned systems. This document states a UAS should demonstrate equivalent levels of safety as manned aircraft, and thus, meet the pertinent federal rules for flight and equipment.
At the US national level, in 2012 Congress passed a bill that mandated the Federal Aviation Administration (FAA) create a plan for allowing UAS into commercial airspace. This past November, the FAA responded by issuing the “Integration of Civil Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) Roadmap.” It sets forth a list of actions required for the safe integration of UAS into the NAS. In addition to referencing the ICAO’s statement, and declaring a harmonization strategy, the FAA also referenced the work of the RTCA (a non-profit industry organization that acts as a Federal Advisory Committee to the US government). RTCA Special Committee 203 (SC-203) has produced numerous documents addressing unmanned aircraft. Among them is DO-320, which states that UAS will require design and airworthiness certification to fly civil operations.
The FAA roadmap is, in essence, maturing the acceptance of UAVs from their current “experimental” standing (which allows them to fly limited missions) to requiring standard airworthiness type certificates (TCs), which will enable broader use and full integration into the NAS. In determining what is required, the FAA is leveraging existing pertinent policy and regulation, while simultaneously identifying unique needs and concerns of UAS.
From a safety perspective, if UAS must conform to the same rules and levels of safety as manned aircraft, given their relative size and weight, they would have to comply with the Code of Federal Regulations Part 14, subpart 23 (14 CFR 23). This regulation covers airworthiness of commuter aircraft. From an equipment perspective, the main concerns are adherence to subparts 23.1301 (function and installation) and 23.1309 (equipment, systems and installation). The primary guidance that addresses development of the complex electronic systems in compliance to these federal rules includes RTCA/DO-178C (“Software Considerations in Airborne Systems and Equipment Certification”) and RTCA/DO-254 (“Design Assurance Guidance for Airborne Electronic Hardware”), along with several other aircraft, systems and safety standards.
To complicate things, it may not just be the “airborne” systems that require compliance. The UAS brain is divided between the UAV itself (which requires onboard “sense and avoid” systems) and the control segment – with the data link between the two playing a crucial role. Not only do these new system aspects need development assurance considerations, they are also pushing the technology adoption envelope in terms of complexity of both hardware and software (a challenging area for the policy makers, even in manned systems today).