As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6494 - ROS-IAD - DURING DESCENT, MADE AN UNSCHEDULED LANDING DUE TO RIGHT ENGINE TORQUE, RPM AND EGT FELL OFF. AIRCRAFT RETURNED TO GATE WITH NO FURTHER PROBLEMS. MAINTENANCE REMOVED AND REPLACED TTL VLV. OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)