THE FLC'S COCKPIT FRONT WINDSHIELD CRACKED AT HIGH ALT CAUSING THE ACFT TO DSND AND LAND AT THE NEAREST APPROPRIATE ARPT. DIVERSION TO ALTERNATE ARPT.

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FLT FROM BOS TO IND WAS RUNNING LATE ON THE NIGHT OF 12/THUR/92. WE WERE INITIALLY CRUISING AT FL350 WELL ABOVE THE WORST WINTER STORM IN 19 YRS WHICH WAS RAGING BELOW. WE WERE ENCOUNTERING LIGHT TO MODERATE CHOP AND SO DSNDED TO FL310 WHERE THE RIDE SMOOTHED OUT. AS WE APCHED AIR VOR; THE FO CALLED MY ATTN TO A CRACK IN HIS OUTER WINDSHIELD. IT WAS GLOWING LIKE DYING COALS IN A FIREPLACE. I TURNED ON THE MAIN COCKPIT LIGHTS TO SEE IF I COULD GET A BETTER LOOK AT THE CRACK. IT SEEMED TO BE GROWING. I REQUESTED AND RECEIVED CLRNC TO DSND TO FL250. I TURNED THE LIGHTS BACK DOWN; TURNED THE SEAT BELT SIGN BACK ON AND IMMEDIATELY CALLED THE FLT ATTENDANTS TELLING THEM TO SIT DOWN AND STRAP IN IMMEDIATELY. WE TURNED THE HEAT OFF TO THE WINDSHIELD AS PER THE CHKLIST. I ALSO CALLED MY DISPATCHER ON THE RADIO AND ADVISED HIM OF OUR PROBLEM. I REQUESTED HIM TO CONTACT MAINT TO SEE IF THEY HAD ANY EXPERIENCE WITH THIS PROBLEM. AS WE WERE PASSING APPROX FL280; THE OUTER WINDSHIELD SHATTERED WITH A LOUD CRACK. ALTHOUGH IT APPEARED THAT NO PIECES OF THE WINDSHIELD SEPARATED FROM THE PANE; THE WINDSHIELD BECAME ALMOST OPAQUE DUE TO THE EXTENSIVE STARRING. THERE WAS NO LOSS OF CABIN PRESSURE. I ADVISED DISPATCH AND MAINT OF THE NEW SITUATION AND THEY CONCURRED WITH MY DECISION TO DIVERT TO PIT WHICH WAS APPROX 30 NM TO THE N. I SLOWED THE ACFT TO 200 KTS AND USED THE SPDBRAKE DURING THE DSCNT. WE ADVISED ATC OF OUR PROBLEM AND TOLD THEM THAT WE WERE NOT IN AN EMER SITUATION AND REQUIRED NO SPECIAL HANDLING OR EQUIP. THE WX AT PIT WAS -X 2 OVCST WITH 1/2 MI VISIBILITY. WE SET UP FOR A CAT III/A AUTOLAND APCH AND BROKE OUT AT CATI MINS; I DISCONNECTED THE AUTOPLT AND LANDED NORMALLY ON THE SNOW COVERED RWY.