Abstract: ON DECEMBER 3, 1985, AT APPROXIMATELY 10 AM., A CREW OF 18 WORKERS WAS LIFTING A WIND TURBINE TO THE TOP OF A 114 1/2' HIGH TOWER, USING A 200 TON TRUCK MOUNTED CRANE WITH A 180 FOOT LONG BOOM. THE LOAD WEIGHT WAS APPROXIMATELY 44 TONS. WEATHER CONDITIONS WERE CLEAR WITH GROUND WINDS MEASURED AT 20 - 25 MPH, WITH GUSTS TO 30 MPH. THE OUTRIGGERS WERE FULLY EXTENDED AT 24', SET ON SOLID GROUND OVER STEEL ROAD PLATES. THE LIFT WAS MADE OVER "THE REAR", WITH 4 TAG LINES IN USE. THE BOOM ANGLE WAS 80 DEGREES, WITH A 35 FOOT RADIUS. AFTER REACHING THE TOP OF THE TOWER THE LOAD WAS SWUNG TO THE RIGHT, OVER "THE SIDE", AND HELD. THE CRANE OPERATOR WAS SIGNALLED TO BOOM UP WHEN THE CRANE STARTED TO TIP. THE BOOM AND LOAD FELLTO THE LEFT, AWAY FROM THE TOWER. THE LOAD CABLES GLANCED OFF THE TOWER. THE LOAD WAS RELEASED TO PREVENT THE CRANE FROM TIPPING. THE BOOM AND LOAD COLLAPSED TO THE GROUND. THREE HIGH VOLTAGE 4 KV ELECTRIC LINES WERE STRUCK AND BROKEN AT THE JOB SITE PERIMETER. SOME HEAVY EQUIPMENT DAMAGE OCCURRED. NO WORKERS WERE INJURED.