Which organization sets standards for security access control systems in aviation?

The correct answer is the Radio Technical Commission on Aeronautics (RTCA), which has established standards and recommendations for aviation security access control systems. RTCA is involved in developing consensus standards that enhance safety and security in aviation technology. These standards serve as a framework for designing and implementing robust security systems that protect airports and their infrastructures from unauthorized access and other security threats.

While other organizations, like the FAA and ICAO, play critical roles in aviation regulation and safety, RTCA specifically focuses on the technical standards applicable to aviation systems, including security access controls. The FAA provides oversight and regulations but does not set specific technical standards. The NTSB's role is primarily investigative, dealing with accident investigations rather than setting access control standards. Thus, RTCA's role in formulating specific recommendations makes it the appropriate answer for this question.