Safety-critical real-time systems must meet stringent timing and fault-tolerance requirements. This article proposes a methodology for synthesizing an optimal preemptive multiprocessor aperiodic task scheduler using a formal supervisory control framework. The scheduler can tolerate single/multiple permanent processor faults. Further, the synthesis framework has been empowered with a novel BDD-based symbolic computation mechanism to control the exponential state-space complexity of the optimal exhaustive enumeration-oriented synthesis methodology.