As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
YIP - REF DME NR 00127 (MRR NR 97-01-27-003/GTIA9700147). AUTOPILOT PORPOISES IN ALL FLIGHT MODES (CLIMB, CRUISE, DESCENT, STABILIZED FLIGHT). FUNCTIONAL CHECK PERFORMED IAW DC-9 MM 22-10-0. READ WIRING TO PITCH CHANNELS. REMOVED AND REPLACED AIR DATA COMPUTER AND PERFORMED PITOT STATIC TEST IAW DC-9 MM 22-10-1. (X)