A FOKKER 100 ON TAXI OUT FROM THE GATE HAD #4 WHEEL AND TIRE ASSEMBLY DEPART THE AIRPLANE. CAUSED BY AXLE NUT AND LOCK BOLTS NOT ALIGNED AND TORQUED.

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ON THE DAY OF OCCURRENCE I VOLUNTEERED TO ASSIST WITH A BRAKE CHANGE ON ACFT X. I ASSUMED THAT UNTIL TODAY THAT IT WAS A NORMAL BRAKE CHANGE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE TWO TECHNICIANS REPLACING THE BRAKE AND TIRE AND WHEEL ASSEMBLY HAD NEVER DONE THE JOB BEFORE AND WERE CLOSE TO FINISHING UP THE JOB. THE RPTR SAID I ASSISTED THEM BY INSTALLING THE AXLE NUT FINGER TIGHT AND ADVISED THEM THE AXLE NUT NEEDED TO BE TORQUED AND THE AXLE NUT LOCK BOLTS NEEDED TO BE ALIGNED WITH THE AXLE NUT SLOTS. THE RPTR STATED THE JOB CARD DOES NOT SPELL OUT CLEARLY THE AXLE NUT POSITION AFTER TORQUING TO ALIGN THE AXLE NUT LOCK BLOCKS WITH THE AXLE NUT SLOTS. THE RPTR STATED HE INSERTED THE AXLE NUT LOCK BOLTS INTO THE AXLE NUT AND LEFT THE JOB. THE RPTR SAID THE WHEEL AND TIRE ASSEMBLY DEPARTED THE ACFT ON TAXI OUT AND SEVERELY DAMAGED THE STRUT AXLE REQUIRING A COMPLETE STRUT REPLACEMENT. THE RPTR STATED THIS WAS THE THIRD INCIDENT OF WHEEL AND TIRE ASSEMBLIES DEPARTING THE ACFT PRIMARILY DUE TO A DEFICIENT JOB CARD NOT CLEARLY DESCRIBING THE AXLE NUT LOCK BOLT ALIGNMENT WITH THE AXLE LOCK SLOT.