As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE ACMS DATA SHOWS INTERMITTENT N2 VALUES FROM OIP REPORT 7. TAKEOFF AND CRUISE ACMS REPORTS SHOW NORMAL PARAMETERS. ACFT GROUNDED. AAVM LOGGED NUMEROUS N2 TACHO LOSS FAULTS. REPLACED NR 1 ENG N2 SENSOR. OP CK NORMAL. REF MM 77-11-01.