As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DTW - FLT 428 - AUTOPILOT PORPOISES SEVERELY WHEN IN VERTICAL SPEED HOLD OR IN ATTITUDE HOLD. PITCH HOLD WORKS OKAY. DEFERRED PER MEL 22-1. DMI NR 00372. REFERENCE DMI NR 00372. RAN COMPLETE CHECK OF AUTOPILOT SYSTEM, IT CHECKS GOOD IAW DC-9 MM 22-00-00. THIS CLEARS DMI NR 00372. (X)