What was found
(CAN) PILOTS REPORTED LOSS OF ALL PITOT-STATIC INSTRUMENTATION ON TAKEOFF - ALL ADC SUPPLIED INSTRUMENTATION FLAGGED & NO INFO FROM STANDBY EQUIP. A/C RETURNED TO AIRPORT. IDENT INHIBIT LIGHT WAS ON - UPON LDG. ALL INSTRUMENTATION RETURNED TO NORMAL. - SUSPECT NR 2 PITOT WAS PLUGGED, WEATHER WAS CLEAR, UFR - BASED ON FAILURE NR 2 PITOT SYS DISASSEMBLED AND BLOWN CLEAR - REASSEMBLED & TESTED PE R ST0571 APPENDIX B STALL 3 SYS RESET & BOTH ADC TESTED, SWITCHING FROM 1-2 TESTED SERVICEABLE, BOTH BACKUP BATTERY PACKS SERVICED & REINSTALLED - UNABLE TO DUPLICATE SNAG. A/C RELEASED ON CONDITION OF SATISFACTORY TEST FLT.- TEST FLT PERFORMED SERVICEABLE ALL EQUIP OP NORMALLY. A/C RT-SRV.