A system and method of detecting an uncontrolled high thrust (UHT) condition in a turbofan gas turbine engine includes processing data to determine when a current commanded fan speed value is greater than a predetermined speed value. A current UHT commanded fan speed value is processed to determine if it will cause a target fan speed value to increase, remain steady, or decrease. The target fan speed value is set equal to the current UHT commanded fan speed value when the current UHT commanded fan speed value will cause the target fan speed value to increase or remain steady, and to a deceleration threshold value when the current UHT commanded fan speed value will cause the target fan speed value to decrease. An uncontrolled high thrust alert signal is generated when actual engine fan speed exceeds the target fan speed value by a predetermined amount for a preset time period.