The Reliability Engineering definition of a system is:
A system is the composite of equipment and skills, and techniques capable of performing or supporting an operational role, or both. A complete system includes all equipment, related facilities, material, software, services, and personnel required for its operation and support to the degree that it can be considered self-sufficient in its intended operational environment.
What this means is that your FRACAS must have a well designed set of policies and procedures as well as a set of roles, goals, and responsibilities for all who are involved in reporting and correcting failures.
A corrective action is a documented design, process, procedure, or material change implemented and validated to correct the cause of a failure or design deficiency.
The key words to remember here are DOCUMENTED, IMPLEMENTED, and VALIDATED. RCA is a part of the FRACAS system, and it is not complete until the recommendations are implemented and validated to ensure that the fix worked.
For more information on FRACAS and other Reliability Engineering Fundamentals, you can sign up to attend the upcoming 3 day RE Fundamentals course in Philadelphia, PA, Dec. 7th-9th. Additional information, including a course abstract can be obtained by clicking here