ENVIRONMENTAL CONTROL SYSTEM

Disclosed is a blower controller (25) for controlling a blower (11) that supplies a pressurised airflow (12) to an air conditioning pack (13) of an aircraft. The blower controller comprises a pack flow demand adjustment module configured to receive a pack flow demand signal (28) representative of a desired mass flow rate of an airflow supplied by the air conditioning pack, and a blower condition signal (41) indicative of a condition of an intake airflow received by the blower, and determine an corrected pack flow demand based on the pack flow demand and the blower condition signal. The controller also includes a first control signal generator (50) configured to receive the corrected pack flow demand (49) and generate a first control signal (26) to control a first operating parameter of the blower in response to the corrected pack flow demand (49). Also disclosed is an environmental control system for an aircraft, including the blower controller.