A flight control system includes a model-based sensor system which estimates angular accelerations to control rotor system moment such that loads on the aircraft structure are reduced to thereby allow an aircraft structural envelope to more closely follow an aircraft service flight envelope. The protective layer preferably contains at least one of carbon and silicon, and the lubricant layer preferably contains fluorine. Batteries that do not exceed the prescribed voltage are not discharged, and thereby all batteries are charged while balancing their voltages.