This article presents a design example of Fault-Tolerant Flight Controllers (FTFCs) and their performance assessment via Hardware-In-the-Loop (HIL) tests with a real airplane. An observer-based robust H∞ design approach is proposed where the states of the observers can be used as virtual sensors for Fault Detection and Isolation (FDI). Two observer-based robust H∞ FTFCs against actuator faults are designed based on whether the observer performance is optimized or not. Their control and observer performances are compared via HIL tests with JAXA’s research airplane MuPAL-α.