High reliability avionic cooling system

In an aircraft having a plurality of compartments to be cooled, a cooling system, comprising:

• a first source of cooling airflow directed through a first duct to a first compartment;
• a second source of cooling airflow directed through a second duct to a second compartment;
• a check valve in said first duct permitting flow from said first source of cooling airflow to said first compartment and preventing a back-flow of air therethrough;
• an interconnecting duct between said first and second ducts, said interconnecting duct connecting to said first duct at a location between said check valve and said first compartment;
• and
• a shutoff valve in said interconnecting duct operable to open or close airflow therethrough;
• wherein said first duct includes a plurality of branches, said check valve being located in one of said branches;
• wherein said first compartment includes regions, each having cooling airflow supplied by separate branches of said duct;
• and
• wherein critical avionics to be cooled are located in a region of said first compartment to which cooling air is supplied by said branch which includes said check valve.

In an aircraft having a plurality of compartments to receive airflow, an airflow system, comprising:

• a first means for providing airflow directed through a first duct to a first compartment;
• a second means for providing airflow directed through a second duct to a second compartment;
• a check valve means operably positioned in said first duct to permit flow from said first airflow means to said first compartment and preventing a back-flow of air therethrough;
• a duct means for interconnecting said first and second ducts, said interconnecting duct means connecting to said first duct at a location between said check valve means and said first compartment;
• and
• said interconnecting duct means including a valve means operable to open or close airflow therethrough;
• wherein said first means draws said airflow from a first source and said second means draws said airflow from a second source, said first and second sources being isolated from each other.

In an aircraft having a plurality of compartments to receive airflow, an airflow system, comprising:

• a first means for providing airflow directed through a first duct to a first compartment;
• a second means for providing airflow directed through a second duct to a second compartment;
• a check valve means operably positioned in said first duct to permit flow from said first airflow means to said first compartment and preventing a back-flow of air therethrough;
• a duct means for interconnecting said first and second ducts, said interconnecting duct means connecting to said first duct at a location between said check valve means and said first compartment;
• said interconnecting duct means including a valve means operable to open or close airflow therethrough;
• and
• operable in a second emergency mode upon failure of said first airflow means, wherein said valve means in said interconnecting duct means is opened and airflow is also supplied to said first compartment by said second airflow means, back-flow of air through said first duct being prevented by said check valve means.