As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE IN CRUISE, FIRST AIR FLIGHT FAB 860 ENROUTE, EXPERIENCED MIDDLE PANE FAILURE ON THE NR 4 LT WINDOW (FWD EYEBROW). THE CREW REQUESTED LWR AND THE ACFT RETURNED TO POINT OF DEPARTURE, LANDING WITHOUT FURTHER PROBLEM. NO EMERGENCY WAS DECLARED. MX REPLACED THE WINDOW AND THE ACFT WAS RETURNED TO SERVICE.