A gas turbine engine system comprising: a gas turbine engine configured to produce a first airflow and a second airflow; a first pneumatic tube configured to receive the first airflow from the gas turbine engine; a second pneumatic tube configured to receive the second airflow from the gas turbine engine; and a dual valve system comprising: a first valve comprising a valve body and a valve disc, the valve body coupled to the first pneumatic tube; and the valve disc operably disposed within the valve body; characterised in that the dual valve system further comprises: a second valve comprising a globe housing and a globe butterfly valve disc, the globe housing comprising a spherical body, the globe housing coupled to the second pneumatic tube; the globe butterfly valve disc operably disposed within the globe housing; and a linkage system operably coupled to the valve disc and the globe butterfly valve disc, wherein the globe housing differs in geometry from the valve body such that opening of a first flow area between the valve disc and the valve body to receive the first airflow from the first pneumatic tube occurs prior to opening of a second flow area between to the globe butterfly valve disc and the globe housing to receive the second airflow from the second pneumatic tube responsive to movement of the linkage system, and in that a travel length along an arc formed by an interior surface of the globe housing results in a delayed opening of the second valve relative to the first valve. a gas turbine engine configured to produce a first airflow and a second airflow; a first pneumatic tube configured to receive the first airflow from the gas turbine engine; a second pneumatic tube configured to receive the second airflow from the gas turbine engine; and a dual valve system comprising: a first valve comprising a valve body and a valve disc, the valve body coupled to the first pneumatic tube; and the valve disc operably disposed within the valve body; characterised in that the dual valve system further comprises: a second valve comprising a globe housing and a globe butterfly valve disc, the globe housing comprising a spherical body, the globe housing coupled to the second pneumatic tube; the globe butterfly valve disc operably disposed within the globe housing; and a linkage system operably coupled to the valve disc and the globe butterfly valve disc, wherein the globe housing differs in geometry from the valve body such that opening of a first flow area between the valve disc and the valve body to receive the first airflow from the first pneumatic tube occurs prior to opening of a second flow area between to the globe butterfly valve disc and the globe housing to receive the second airflow from the second pneumatic tube responsive to movement of the linkage system, and in that a travel length along an arc formed by an interior surface of the globe housing results in a delayed opening of the second valve relative to the first valve. a first valve comprising a valve body and a valve disc, the valve body coupled to the first pneumatic tube; and the valve disc operably disposed within the valve body; characterised in that the dual valve system further comprises: a second valve comprising a globe housing and a globe butterfly valve disc, the globe housing comprising a spherical body, the globe housing coupled to the second pneumatic tube; the globe butterfly valve disc operably disposed within the globe housing; and a linkage system operably coupled to the valve disc and the globe butterfly valve disc, wherein the globe housing differs in geometry from the valve body such that opening of a first flow area between the valve disc and the valve body to receive the first airflow from the first pneumatic tube occurs prior to opening of a second flow area between to the globe butterfly valve disc and the globe housing to receive the second airflow from the second pneumatic tube responsive to movement of the linkage system, and in that a travel length along an arc formed by an interior surface of the globe housing results in a delayed opening of the second valve relative to the first valve. a second valve comprising a globe housing and a globe butterfly valve disc, the globe housing comprising a spherical body, the globe housing coupled to the second pneumatic tube; the globe butterfly valve disc operably disposed within the globe housing; and a linkage system operably coupled to the valve disc and the globe butterfly valve disc, wherein the globe housing differs in geometry from the valve body such that opening of a first flow area between the valve disc and the valve body to receive the first airflow from the first pneumatic tube occurs prior to opening of a second flow area between to the globe butterfly valve disc and the globe housing to receive the second airflow from the second pneumatic tube responsive to movement of the linkage system, and in that a travel length along an arc formed by an interior surface of the globe housing results in a delayed opening of the second valve relative to the first valve.