What was found
AT FL 360 & FLYING THROUGH MOD RAIN REC EICAS, SPS ADVANCED, PLUS THE IAS ON THE CAPTAINS SIDE HAD A DIFFERENCE OF 40 KTS FROM FIRST OFFICERS SIDE. ALSO FIRST OFFICERS SIDE TO CAPTAINS SIDE WAS OFF BY 200 FT. CAPTAINS & STANDBY WAS CORRECT. DESCENDING THROUGH FL 200, FIRST OFFICER AIRSPEED & ALT RETURNED TO NORMAL. DRAINED WATER FROM PITOT STATIC SYS 1 & 2 IAW AMM 34-13-00. ADC SYS OPERATIONS CHECKS GOOD IAW AMM 34-15-00. STALL PROTECT SYS OPERATIONS CHECK GOOD IAW AMM 27-36-00.