What was found
(CAN) DIVERTED DUE TO AIRSPEED SPLIT DURING TAKEOFF/CLIMB. ON TAKEOFF CREW NOTICED A 2-3 KTS SPLIT BETWEEN CAPTAIN AND F/O AIRSPEED INDICATORS. AIRBORNE THE SPLIT WENT TO 1 KT AND REMAINED THERE. ON LANDING THE IAS DISAGREE MESSAGE APPEARED FOR 1-3 SEC BELOW 60KTS. MAINTENANCE FOUND THE DEU SHOWS AIRSPEED DISAGREE MSG. 31-65060, PERFORMED FIM 31-62T876 AND REPLACED NR 1 ADM, PITOT, DUE TO UNSATISFACTORY AIR DATA SYS REF TEST AND SYS TESTS SERVICEABLE IAW AMM 34-21-00. PART HAS BEEN SENT FOR REPAIR. THE SDR WILL BE UPDATED WITH TEARDOWN INFORMATION WHEN AVAILABLE. PART REMOVED: PN: C17001CA01, SN: 5205, POSITION: LT INSTALLED: HRS 29007:28, CYCLES 13742.