As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPTAIN`S AIRSPEED UNRELIABLE DURING DESCENT. LOST 40KTS ACCORDING TO IT THEN A GAIN OF AROUND 60KTS WITH NO THRUST CHANGE. REMOVED AND REPLACED THE NR 1 ADC IAW AMM 34-15-01, OPERATES OK IAW AMM 34-15-00, PITOT/STATIC LEAK CHECKED OK IAW AMM 34-13-00.