What was found
(CAN) DURING THE 1ST REVENUE FLIGHT ON THIS NEW ACFT, THE NR 1 FUEL FILTER BYPASS MESSAGE ILLUMINATED ON LANDING. THE NR 1 FUEL FILTER PRESSURE SWITCH, PN 3122426-04, SN HE1372 WAS REPLACED. THE DEFECT STILL EXISTED SO THE NR 1 AND NR 2 PRESSURE SWITCHES WERE SWAPPED FOR T/S AND THE FAULT FOLLOWED. THEREFORE IT WAS DETERMINED THAT THE NEW PRESSURE SWITCH WAS UNSERVICEABLE FROM STOCK, PN 3122426-04, SN HE1437. THE ACFT WAS FERRIED TO A MAINTENANCE BASE WHERE THE FAULTY SWITCH WAS REPLACED AND THE ACFT RETURNED TO SERVICE.