What was found
WINDOW CRACKED FROM TOP TO BOTTOM, BEGINNING WHERE IT IS OVERLAPPED BY LOWER DOOR HINGE. EXTREMELY COLD WEATHER, -10 DEGREES F, CAUSED WINDOW TO BECOME INFLEXIBLE. WINDOW LIKELY CRACKED WHEN TOO MUCH PRESSURE WAS APPLIED TO THE DOOR WHILE IT WAS OPEN. PILOTS AND CREWS WERE CAUTIONED NOT TO APPLY EXCESSIVE FORCE ON THE DOOR WHILE OPEN OR USE IT FOR SUPPORT AHILE CLIMBING INTO OR OUT OF ACFT.