As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRPLANE HAS PITCH OSCILLATION (PORPOISES) WITH ANY A-P CHANNEL IN CMD AND (V-S, ALT HOLD, FLCH, VNAV) MODE SELECTED. SUSPECT THRUST MANAGEMENT COMPUTER. REPLACED THRUST MANAGEMENT COMPUTER, GROUND TEST OK. AUTOPILOT CAT III CKS GOOD. ACFT OK FOR SERVICE