What was found
THIS AIRCRAFT USES DUAL VACUUM PUMPS. THESE PUMPS ARE CONNECTED TO THE VACUUM SYSTEM VIA A MANIFOLD ASSEMBLY. THIS MANIFOLD PERFORMS TWO IMPORTANT FUNCTIONS, ONE TO ALLOW FOR A COMBINED SOURCE OF VACUUM FROM THESE TWO PUMPS, AS WELL AS PROVIDE AN ISOLATION FUNCTION SHOULD ONE PUMP FAIL. THIS MANIFOLD VALVE, IS ASSEMBLED USING SMALL ALUMINUM RIVETS. THEY HAVE BEEN FAILING ALLOWING THE MANIFOLD VALVE TO SEPARATE WHILE MOUNTED ON THE FIREWALL. THIS RENDERS THE ENTIRE VACUUM SYSTEM INNOPERATIVE, AND COMPLETELY DISCONNECTS THE TWO PUMPS FROM THE SYSTEM.