What was found
(CAN) DURING TAXI WITH THE WINDSHEILD HEAT SELECTED ON THE RT COCKPIT HEATED WINDSHEILD CRACKED. THE FLIGHTCREW RETURNED TO THE TERMINAL AND THE AIRCRAFT WINDOW HAS BEEN REPALCED BY MAINTENANCE. NO CAUSE OF THE CRACKED GLASS COULD BE DETERMINED. THIS IS THE THIRD FAILURE OF A HEATED WINDSHEID THIS COMPANY HAS INCURRED SINCE JAN 1, 2007. 12 WERE REPORTED IN 2006. OTHER AIRCRAFT OPERATORS OF THIS TYPE OF AIRCRAFT HAVE BEEN CONTACTED AND ARE INCURRING SIMILAR FAILURE RATES. (TC NR 20070208005)