Diagnosis of large and complex software systems is a challenging task that can highly benefit from monitoring of the highlevel functional requirements. This work studies the potential of applying requirements monitoring for a software system of high complexity: the combat management system (CMS) of a modern and technologically advanced naval platform. An effort is made to apply the requirements monitoring method for autonomizing of this system while limiting implementation impact. The KAOS goaloriented requirements engineering method is used to extract software system goals from previously documented requirements. With these high-level objectives as a starting point, the ReqMon requirements monitoring framework is applied. An implementation model is defined, identifying what data transformations are needed to apply the ReqMon system. Tests with a requirements monitoring prototype demonstrate that detailed diagnosis of a complex software system as a CMS is feasible and furthermore that comprehensive manual fault analysis can be replaced by an automated process: the first step towards a self-healing autonomic combat management system is taken.