For mission critical systems, many companies and governmental organizations require certified software products and/or development processes. Companies developing such systems need to achieve certain system availability requirements by domain-specific certification standards or informal assurance techniques at competitive cost and time. System availability is an important metric for certification of the systems, and it is affected by design of operation procedures for the systems. To improve system availability to the required level with the minimal effort, it is essential to find the operations whose improvements can achieve the system availability requirements. This paper proposes a method to identify the operations whose improvements are necessary to achieve desired system availability in operation procedures, and to recommend means to improve the operations. We demonstrate a case study of applying the proposed method to an operation procedure of a real database. We succeeded in identifying operations to be improved to achieve certain system availability requirements in an operation procedure and providing a reasonable recommendation to improve system availability.