What was found
INBOUND TO ONT FAILURE FLAGS DISPLAYED ON CAPTAINS AIRSPEED IND, VMO POINTER, MACH ASI, ALTIMETER, VSI FAIL AND SPEED TAPE FAIL ON CAPT''S HORIZON GPWS ALSO FAILED. RESET ADC CIRCUIT BREAKER, RERACKED NR 1 AND 2 ADC, POWERED DOWN AND POWERED UP AIRCRAFT. ALL SYS OPS CHECKED GOOD. REPLACED NR 1 ADC AS PRECAUTION IAW 34-12-11.