As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 INERTIAL NAVIGATION SYSTEM FAILED AFTER TAKEOFF DISPLAY WAS BLANK WITH RED WARNING LIGHT ON. NR 3 INERTIAL NAVIGATION SYSTEM HAS ADC AND MX RQD FLASHING IN STATUS DISPLAY. AIRCRAFT RETURNED TO SIN. REPLACED NR 1 INU AND ALIGNED PER M/M 34-41-00. PLACARDED NR 3 INU PER MEL 34-27-1.