As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MODE CONTROL PANEL AIRSPEED CONTROL KNOB IN APP MODE ON FINAL APPROACH WAS INTERMITTENTLY LOCKED UP - BOTH TIMES EVENTUALLY ALLOWED US TO CONTROL THE IAS. GROUNDED - YES. R & RD DFCS MODE CONT PNL PER AMM 22-11-34 C/B'S PULLED/TAGGED AND UNTAGGED/RESET (9). SYS OPS CKS NML PER SAME.