What was found
TWICE DURING FLIGHT (ONCE ON CLIMB OUT AND ONCE ON DESCENT), LEFT PILOT LOST ALL AIRSPEED, ALTITUDE AND VERTICAL SPEED INDICATIONS, WITH ASSOCIATED RED FLAGS, LOSS OF AUTOPILOT, LOSS OF AUTO THROTTLE, AND MACH TRIM FAIL. DURING THE SECOND EVENT (ON DESCENT AT APPROXIMATELY 3000 FEET), BOTH PILOTS LOST ALL AIRSPEED, ALTITUDE AND VERTICAL SPEED INDICATIONS. IN BOTH EVENTS, THE FAILURE LASTED BETWEEN 5-10 SECONDS BEFORE RETURNING TO NORMAL. MACH TRIM, AUTO THROTTLE AND AUTOPILOT WERE ALL RESET AND LANDING WAS UNEVENTFUL. CORRECTIVE ACTION: REPLACED ADC 1 IAW AMM 34-13-01. OPS AND LEAK CHECKS GOOD.