As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6578 - IAD-PWM - DURING CRUISE, MADE A UNSCHEDULED LANDING AT IAD DUE TO NR 1 INVERTER FAILED. AIRCRAFT RETURNED TO GATE WITH NO FURTHER PROBLEMS. MANTENANCE INSPECTED AND REMOVED AND REPLACED NR 1 INVERTER, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)