What was found
AIRCRAFT WAS GROUNDED: DURING VERY SHORT FINAL APPROACH AROUND 200 AGL THE CAPTAIN AIRSPEED INDICATION QUICKLY CHANGED FROM ON TARGET APPROACH SPEED TO ABOUT MINUS 10-15 KNOTS . THE FIRST OFFICER AIRSPEED REMAINED NORMAL STANDBY ATTITUDE AIRSPEED ALSO NORMAL . THIS TRIGGERED A AIRSPEED SLOW AURAL WARNING WHICH CAUSED US TO GO AROUND EMERGENCY WAS DECLARED. FOUND BUG REMAINS ON FLUSHING OF CAPTAIN PITOT SYSTEM TUBE AMM 34-11-00, ACCOMPLISHED AIR SPEED DISAGREE MAINTENANCE TASK PER AMM 31-62-00, ALL INDICATION NORMAL ON GROUND CHECK OUT.