As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT STAB CHANNEL 1 DISENGAGED, ABLE TO REENGAGE NO PROBLEM DURING APPROACH BOTH STAB TRIM AND MACH TRIM FAILED, UNABLE TO REENGAGE. AIRCRAFT CONFIGURATION WAS AUTOPILOT OFF, FLAPS 20 AND TRIM 3.8 COMPLIED WITH QRH AND LANDED. FIRST OFFICERS STAB TRIM DISCONNECT SWITCH FOUND AT FAULT. REMOVED AND REPLACED PER AMM 27-41-30-400-802. (M)