What was found
ETOPS SIGNIFICANT SYSTEM, FIRST OFFICERS AIRSPEED IND INSTRUMENT AND EFIS A/S MACH INDICATOR WENT OVERSPEED AT CRUZ ALT 35000 ALSO F/O'S ALTIMETER CLIMBED 600'. SWITCHED F/O'S AIR DATA SOURCE SELECTOR TO ALTERNATE POSITION. T/S PER FIM 34-12-00 FIG 109. TEST OF RIGHT ADC NORMAL. NO FAULTS TEST OF LEFT ADC NORMAL. NO FAULTS. INSPECTED F/O PITOT PROBES AND LINES. NO FAULTS. NO EXT SENSOR FAULTS ON EITHER ADC PERFMD MCDP LAST FLT AND NR 30 TEST NO FLTS. REMOVED AND REPLACED F/O'S ADC PER AMM 34-12-01-006, TEST 30, NO FLTS.