In this paper, how to obtain motor speed signals for multirotor flight states to avoid a crash in the case of complete motor failures based on the Euler angle state variable approach is explained. First, the mathematical foundation for a multirotor as a rigid body is introduced. Secondly, state equations, maneuvers, and flight states (or flight operating points) of multirotors are summarized. Thirdly, in the case of complete motor failures, definitions of the motor speed control signal vector of the remaining motors and a method of directly providing motor speed control signals to achieve flight states to avoid a crash are provided. Finally, the method is applied to the problem of a multirotor vehicle experiencing motor failures. Numerical simulation results are also illustrated. In addition, the mathematical backgrounds of the Euler angle state equations of the multirotor and the proposed method are precisely explained in the appendices.