What was found
LANCAIR IV-P, WHILE IN PRESSURIZED CRUISE FLIGHT AT 15,500' MSL AND 245KTS, A LARGE PORTION OF THE WINDSHIELD FRACTURED AND SEPARATED FROM THE AIRCRAFT. AN IMMEDIATE DEPRESSURIZATION OCCURRED, RESULTING IN AN EMERGENCY LANDING. VISUAL INSPECTION REVEALED NO OBVIOUS DAMAGE, SUCH AS IMPROPER CLEANSERS, NICKS, SCORING, SCRATCHES, ETC., THAT CONTRIBUTED TO THE WINDSHIELD FAILURE.