What was found
IAS COMPARATOR AND "SEL ELEV FEEL MAN" AND "SEL FLAP LIM OVRD". CAPTAIN AIRSPEED 9 KNOTS SLOWER THAN F/O AND SBY. CAPTAIN SHOWED 35 KNOT TAILWIND WITH A 3 KNOT HEADWIND ON F/O SIDE. APPRX FL160 HAD MODERATE PRECIP WHEN FIRST FAULT "IAS COMPARATOR" SHOWED. SHORTLY AFTER HAD A/P TRIP. CAPT SWITCHED TO CADC 2 FOR REMAINDER OF FLT. . FCC 1&2 HAVE 12 FAULTS CORRELATING TO DEBRIEF, RESULTING FROM "ADIRU-1 AD/ADIRU-2 AD" "TAS INV" AND "CAS INV" INCLUDING "A/T SNGL", "P F/D BOV", "A/P DISC", "F/L SNGL" AND "ELF SNGL". FACT 02JUN19 05:10 SLC U FOUND CAPT PITOT DRAIN OBSTRUCTED (NOT TOTALLY PLUGGED), WATER WAS SLOWLY SEEPING OUT, CLEARED DRAIN HOLES AND DRAINED APPRX 5CC'S OF REMAINING WATER. CHECKED F/O AND SBY PITOT DRAINS - NO OBSTRUCTIONS. BACK PURGED PITOT LINE FROM ADM Q/D FITTING UNTIL WATER WAS GONE. BLEW OUT SOME MINOR DEBRIS, BUT NO BUGS PUMPED UP CAPT PITOT SYSTEM, VERIFIED NO LEAKS AND IAS MATCHED TESTER AT VARIOUS SPEEDS. CHKD PITOT HEAT, OPS NML. REF AMM 34-11-00-2, 34-16-01-4 AND 34-16-00-5-1. PERF AUTO LAND SYSTEM RETURN-TO-SERVICE TEST ON EACH FCC (1 AND 2), ALL TESTS PASSED, 30-DAY PERIODIC AUTOLAND TIMER RESET - REF AMM: 22-00-00-2.