What was found
ON TAKEOFF ROLL NO AIRSPEED INDICATED ON F/O'S INDICATOR. AIRSPEED ON CAPT'S & STBY AIRSPEED CHECKED GOOD. TAKEOFF ABORTED AT 70KTS WITH STILL NO INDICATION ON F/O'S SIDE. TROUBLESHOT TO A FAILED NR 2 ADC. REMOVED FAILED UNIT & INSTALLED OVERHAULED UNIT. ACCOMPLISHED SATISFACTORY LEAK TEST. FUNCTIONAL TEST & RECERT UP TO 47000 FT. TRANSPORTER ALTITUDE CORRESPONDENCE CHECK GOOD IAW INSP PITOT TUBES FOR OBSTRUCTIONS, NONE. PURGED PITOT LINE, NO DEBRIS. PERFORMED CHECK OF F/O'S AIRSPEED NOTED SPEED VERY SLOW TO RISE TO SELECTED SPEED, NOTED. LEAK RATE ONLY 4 OF KT/ P/MIN. SPEED VERY SLOW TO RUN DOWN. ATTEMPTED SEVERAL TIMES AT DIFFERENT SPEEDS NOTING SAME RESULTS. REMOVED PITOT LINE AT TADC & CONNECTED PITOT, TESTED DIRECTLY TO ADC PORT. AIRSPEED INDICATIONS REMAINED VERY SLOW TO REACT. CONTINUED MCC & DEBRIEFED WITH RESULTS. ADC OPER. INSTALLED ALL PITOT/STAIL PROTECTORS. REMOVED PITOT/ STATIC LINES FROM NR2 ADC. REMOVED ADC. INSTALLED OVERHAULED UNIT. COMPLIED WITH ADC RECERTIFICATION & LEAK CHECKS GOOD. INSTALLED COCKPIT SIDE PANEL. FUNCTIONAL TEST LEAK CHECK & RECERT UP TO 47,000 FT INCLUDING RVSM REQUIREMENT IAW FAR 91-411 AND MM W/O'S 34-100, 34101, 34-102, 34-103, 103-104 AND 34-507. TRANSPONDERS TESTED FOR ALTITUDE CORRESPONDENCE IAW PART HPE OF PRT 43.