As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
KAPA - KRSW TRIP ID NR 898928, THE CREW REPORTED THAT THE ELEVATOR TRIM FROZE AT FL 350 WITH AN OUTSIDE AIR TEMPERATURE OF -35 DEGREES AT APPROXIMATELY 90 MINUTES INTO THEIR FLIGHT. NO PRECIPITATION WAS ENCOUNTERED FROM THE GROUND UP TO THIS POINT OF FLIGHT. AFTER DESCENDING TO 12,000 FT THE PROBLEM WAS RESOLVED. MAINTENANCE LUBRICATED THE ELEVATOR TRIM ACTUATOR. OPERATIONAL CHECKS WERE GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.