As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6552 - IAD-CLE - DURING CRUISE, MADE AN UNSCHEDULED LANDING DUE TO LEFT VSI INOP. AIRCRAFT RETURNED TO THE GATE WITH NO FURTHER PROBLEMS. MAINTENANCE INSPECTED AND REMOVED AND REPLACED VSI, OPS CHECK OK. AIRCRAFT WAS RELEASED AND RETURNED TO SERVICE. (M)