As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6551 - IAD-CLE - DURING CRUISE, MADE AN UNSCHEDULED LANDING DUE TO LT RPM DROPPED TO ZERO. AIRCRAFT RETURNED TO GATE WITH NO FURTHER PROBLEMS. MAINTENANCE INSPECTED AND REMOVED AND REPLACED TACH GENERATOR, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURNED TO SERVICE. (M)