A method of optimizing an operation of a rotorcraft includes measuring actual usage of the tail rotor drive shaft during operation of the rotorcraft, the actual usage including at least a torque measurement. The method further includes a step of adjusting a life of the tail rotor drive shaft based upon the measuring of the actual usage. Another method of the present disclosure includes determining a main rotor mast torque by measuring a tail rotor drive shaft torque and deriving a main rotor mast torque by considering the measured tail rotor drive shaft torque and a total torque output of an engine. A system of the present disclosure is configured for determining the main rotor mast torque in part by measuring the tail rotor torque.