Abstract: A GROVE 35 TON MOBILE CRANE HAD BEEN SET UP TO MOVE PLYWOOD SHEETS INTO AN EXCAVATION. THE BOOM HAD TO BE EXTENDED 85 TO 90 FEET (OUT OF A POSSIBLE 104 FEET) TO DO THE WORK. ON THE FIRST LIFT, THE CRANE WAS LIFTING 6 SHEETS OF PLYWOOD WITH THE BOOM AT ABOUT A 60 TO 65% ANGLE. THE OUTRIGGERS WERE EMPLACED, BUT NOT FULLY EXTENDED. THE CRANE OPERATOR EXPERIENCED A "CREEPING" SENSATION, WHICH CAUSED HIM TO DISMOUNT THE CRANE AND CHECK THE OUTRIGGERS. HE FOUND THAT THEY WERE ALL IN CONTACT WITH THE GROUND. HE RESUMED THE LIFT, BUT AGAIN EXPERIENCED THE CREEPING SENSATION. HE STARTED TO PULL THE BOOM IN, BUT WITHIN 30 SECONDS THE CRANE TIPPED OVER TOWARD THE EXCAVATION. THE OPERATOR JUMPED FREE AND WAS NOT INJURED. THE CRANE WEDGED ITSELF AGAINST AN EXISTING BUILDING, WHICH KEPT IT FROM FALLING INTO THE EXCAVATION. IF TIME HAD BEEN TAKEN TO CLEAR THE AREA OF MATERIALS, AND THE OUTRIGGERS HAD BEEN FULLY EXTENDED, IT IS DOUBTFUL THAT THE ACCIDENT WOULD HAVE OCCURRED. THE EMPLOYER WILL BE CITED FOR FAILURE TO COMPLY WITH MANUFACTURER'S OPERATING PROCEDURES.