What was found
ON DESCENT WHILE SELECTING DFGC 2, THE ATTITUDE SELECTOR WENT BLANK, IT ILLUMINATED. WHEN IT WENT BLANK, THE AUTO PILOT & AUTO THROTTLES KICKED OFF & THE FIRST OFFICER LOST THE FLIGHT DIRECTOR, WHEN IT CAME BACK ON WE WERE ABLE TO RESELECT ALL MODES. HOWEVER 2 - 3 MINS LATER THE CAPTAINS ALTIMETER & AIRSPEED BECAME ERRATIC & EVENTUALLY COMPLETELY FAILED. WITH OFF FLAGES THE AUTO FLIGHT & AUTO THROTTLES KICKED OFF AGAIN. AFTER RUNNING QRH 31.2 & SELECTING CADC 2 WE WERE ABLE TO RE-ENGAGE ALL AUTOMATION & CONTINUED AS NORMAL. PERFORMED RTS TEST ON 1 & 2 SYSTEMS, BOTH PASSED GO & IAW MM 22-05-01 & PERFORMED CADC TEST BOTH PASSED IAW MM 34-16-01.