An air turbine starter (ATS) assembly includes a rotatable pinion gear (72) wherein the rotatable pinion gear is coupled to a combustion engine (10), a speed sensor (78) measuring the rotational speed (302) of the rotatable pinion gear (72), a torque sensor (79) providing a torque output (304) indicative of a torque experienced by the pinion gear (72), and a controller module configured to operate a starting sequence for the ATS assembly such that the rotational speed (302) is controllably increased while the torque output (304) is kept below the start sequence torque threshold (310).