What was found
DURING CRUISE, DECLARED AN EMERGENCY, AFTER LOSING BOTH NR 1 & 2 AIR DATA SYSTEMS. INITIALLY RECEIVED MACH TRIM INOPERATIVE LIGHT FOLLOWED BY DUAL AUTOTHROTTLE AND AUTOPILOT DISENGAGEMENT. CAPTAIN`S & F/O`S AIRSPEED INDICATIONS SUBSEQUENTLY BECAME UNRELIABLE. LANDED SAFELY USING STANDBY INSTRUMENTS ONLY. MX REPLACED BOTH AIR DATA COMPUTERS IAW AMM 34-16-01 AND ALSO REPLACED THE RAT PROBE IAW AMM 34-1 WITH ALL SUBSEQUENT CHECKS OK. A VERIFICATION FLIGHT WAS PERFORMED AFTER MAINTENANCE. THE ACFT WAS RETURNED TO SERVICE.