As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ASYMMETRICAL THRUST PROBLEM. ENGINE NR 1 WOULD NOT PRODUCE THRUST ABOVE 51 PERCENT N1. ATC WAS NOTIFIED OF POSSIBLE PROBLEM AND FIRE AND RESCUE WAS REQUESTED TO BE ON STANDBY. *S/D* REPLACED THE MAIN ENGINE CONTROL. AIRCRAFT RETURNED TO SERVICE. NO FURTHER ANOMALIES NOTED.