Abstract: AN EMPLOYEE HAD BEEN PERFORMING LINE CLEARANCE TREE TRIMMING FOR AN ELECTRIC UTILITY. HE WAS WORKING FROM THE BUCKET OF AN AERIAL LIFT (SKYWORKER: MODEL NO. 10358, SERIAL NO. 41239) MOUNTED ON A 1974 FORD F-600 TRUCK. HE HAD COMPLETED HIS TRIMMING FOR THE DAY AND WAS MANEUVERING THE AERIAL LIFT INTO THE CRADLE POSITION FOR HIGHWAY TRAVEL. THE TOP OF THE BUCKET WAS ABOUT 30 FEET ABOVE THE GROUND. AT THIS POINT, THE UPPER BOOM KNUCKLE CASTING BROKE. THE BUCKET STRUCK THE FRAME FOR THE BOOM CRADLE, LOCATED NEAR THE REAR OF THE TRUCK BED. THE FORCE PROPELLED THE EMPLOYEE HEAD-FIRST TO THE GROUND NEAR THE LEFT REAR CORNER 0F THE TRUCK BED. HE WAS TRANSPORTED TO A HOSPITAL, WHERE HE WAS PRONOUNCED DEAD ON ARRIVAL.