# In cruise performance the fuel mass flow determines the rate

In cruise performance the fuel mass flow determines the rate of change of mass of the aircraft.

A. True

B. False

For explanation I would say: In cruise performance the fuel mass flow determines the rate of change of mass of the aircraft. It is expressed by the formula Qf=$$\frac{-dm}{dt}$$ where dm is mass rate and dt is time rate. The fuel mass is always negative as mass of the aircraft always decreases.