Digitally augmented pneumatic control

An aircraft comprising:

• an environmental control system for conditioning air;
• a bleed air system for providing a flow of air to the environmental control system;
• and
• a valve arranged within a flow path of the flow of air provided to the environmental control system;
• an airflow control system arranged between the bleed air system and the environmental control system, the airflow control system including:
• a sensor for measuring a pressure of the flow path downstream of the valve;
• and
• a pneumatic controller and a digital controller, the pneumatic controller and the digital controller being independently operable to regulate a pressure of the flow of air provided to the environmental control system, wherein both the pneumatic controller and the digital controller are configured to regulate a pressure of the flow of air based on a pressure of the flow of air downstream from the valve, the digital controller being operable in response to the pressure measured by the sensor and a digital set point, the digital set point being adjustable to compensate for inaccuracy of the pneumatic controller;
• wherein the pneumatic controller includes a lever, a biasing member connected to a first end of the lever and a second valve arranged at the second end of the lever, wherein the biasing member biases the lever and the second valve toward a closed position.

A method of regulating a pressure of a flow of air comprising:

• providing a valve positioned within a duct, the valve being adjustable to control a flow of air through the duct;
• providing a portion of the flow of air from the duct, downstream of the valve, to a pneumatic controller, the pneumatic controller including a lever, a biasing member connected to a first end of the lever and a second valve arranged at the second end of the lever, wherein the biasing member biases the lever and the second valve toward a closed position;
• pivoting the lever to adjust a position of the second valve of the pneumatic controller in response to determining that the pressure of the downstream portion of the flow passage exceeds the regulation pressure set point of the pneumatic controller;
• sensing a pressure within the duct downstream from the valve via a sensor and communicating the pressure to a digital controller,
• determining if the pressure of the portion of the flow of air exceeds a regulation pressure set point of the pneumatic controller;
• comparing the sensed pressure to a digital set point when the pressure of the portion of the flow of air is below the regulation pressure set point;
• and
• operating a torque motor operably coupled to the valve to adjust a position of the valve in response to the comparison of the sensed pressure and the digital set point;
• and
• adjusting the digital set point based on a sensed pressure to compensate for inaccuracy of the pneumatic controller.