What was found
(CAN) THE AIRCRAFT TOOK OFF ON A ROUTINE MEDIVAC FLIGHT. THEY LEVELED OFF AT FLIGHT LEVEL 260 AND APPROXIMATELY 10 MINUTES INTO THE FLIGHT A LOUD BANG WAS HEARD AND THE COPILOT NOTICED THE FRONT WIND SCREEN ON HIS SIDE HAD SEVERAL LARGE CRACKS ON THE OUTER PLY. THE CREW DECIDED TO LAND AT A MAINTENANCE BASE WHERE PERSONNEL CONFIRMED THE CRACKS IN THE OUTER PLY. THE AIRCRAFT WAS RELEASED TO FLY BACK TO MAIN BASE AS PER CHAP 4 OF THE AIRWORTHINESS LIMITATIONS MANUAL. THE WIND SCREEN WAS REPLACED WITH A SERVICEABLE UNIT. THE CREW CONFIRMED THAT WINDSHIELD HEAT WAS ON DURING THIS PORTION OF THE FLIGHT AS THEY HAD JUST PASSED THROUGH ICING CONDITIONS.