Dual inline starter air valve

A method of operating a starter air valve comprising a housing having an inlet at a first end, an outlet at a second end opposite the first end, and a center portion between the first end and the second end, the outlet being fluidly connected to the inlet through a fluid passage, the method comprising:

• regulating the airflow through the fluid passage using a first piston located within the housing between the first end and the center portion, the first piston comprising:
• a first cupped portion configured to form a first chamber with the housing proximate the first end;
• and
• a second cupped portion opposite the first cupped portion, the second cupped portion being configured to form a second chamber with the housing proximate the center portion;
• and
• regulating the airflow through the fluid passage using a second piston located within the housing between the second end and the center portion, the second piston comprising:
• a third cupped portion configured to form a third chamber with the housing proximate the second end;
• and
• a fourth cupped portion opposite the third cupped portion, the fourth cupped portion being configured to form a fourth chamber with the housing proximate the center portion;
• wherein the first piston is configured to regulate airflow through the fluid passage by adjusting at least one of a first pressure within the first chamber and a second pressure within the second chamber,
• wherein the second piston is configured to regulate airflow through the fluid passage by adjusting at least one of a third pressure within the third chamber and a fourth pressure within the fourth chamber,
• wherein movement of the first piston in either a first direction or a second direction is caused by a balance of forces created solely by the first pressure within the first chamber and the second pressure within the second chamber, and
• wherein movement of the second piston in either the first direction or the second direction is caused by a balance of forces created solely by the third pressure within the third chamber and the fourth pressure within the fourth chamber.