What was found
ON FINAL APPROACH, AT 500 FEET AGL, THE CAPTAIN'S AIRSPEED INDICATOR READ 25 KNOTS SLOWER THAN THE FIRST OFFICER'S INDICATION. JUST BEFORE LANDING, THE POWER SURGED TO TOGO WITHOUT PILOT INPUT. THE PILOT FLYING PULLED THE POWER BACK TO IDLE AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE NR 1 PROBE HEAT COMPUTER. OPERATIONALLY CHECKS OK.