THE #1 AND #2 MAIN TIRE ASSEMBLIES OF AN FK10 WERE CHANGED BY AIRLINE MAINT. DURING CHKS; THE #1 TIRE WOULD NOT SPIN BECAUSE THE #1 BRAKE ASSEMBLY WAS LOCKED. AFTER THE #1 BRAKE ASSEMBLY WAS REPLACED; THE ACFT DEPARTED THE GATE. DURING TKOF; THE #1 WHEEL CAME OFF AND THE FLC RETURNED TO THE ARPT AFTER DECLARING AN EMER.

Narrative

ACFT ARRIVED AT GATE WITH #1 TIRE FLAT. ANOTHER MECH AND MYSELF; ALONG WITH LEAD MECH; PROCEEDED TO GATHER UP PROPER TOOLS AND PERTINENT PARTS TO CHANGE BOTH #1 AND #2 MAIN TIRE ASSEMBLIES. WE THEN PROCEEDED TO JACK ACFT UP; AND REMOVED #1 TIRE FIRST. WE THEN REMOVED AND REPLACED #2 TIRE ASSEMBLY. WE THEN BEGAN INITIAL TORQUING OF BOTH #1 AND #2 AXLE NUTS. WE FOUND #2 TIRE WOULD SPIN OK; WITH BRAKES OFF; BUT #1 TIRE WOULD NOT SPIN. WE THEN REMOVED #1 TIRE ASSEMBLY AND DETERMINED #1 BRAKE ASSEMBLY WAS LOCKED IN 'BRAKES ON' POS. WE THEN PROCEEDED TO REMOVE AND REPLACE #1 BRAKE ASSEMBLY. WE REINSTALLED #1 TIRE ASSEMBLY AND RESUMED WITH INITIAL TORQUING OF BOTH AXLE NUTS; PER MAINT MANUAL SPECS. WE THEN APPLIED FINAL TORQUING OF BOTH AXLE NUTS PER MAINT MANUAL SPECS. WE INSTALLED ALL RETAINING BOLTS TO BOTH AXLE NUTS AND SAFETIED THEM. WE INSTALLED BOTH AXLE COVERS; AND SAFETIED THEM. WE FILLED OUT ALL PAPERWORK AND MADE PROPER ENTRIES IN ACFT LOGBOOK. WE CLRED ACFT OF ALL USED PARTS AND TOOLS AND WE DEPARTED GATE AREA. THE ACFT TAXIED OUT FOR TKOF. ON TKOF; #1 TIRE AND BRAKE CAME OFF ACFT AND CAME TO REST ON RWY. ACFT RETURNED TO ARPT WITH NO INJURIES TO PAX ON BOARD; AND NO DAMAGE TO ACFT. INSPECTION SHOWED ALL BOLTS AND COVERS SAFETIED AND IN PLACE -- BOTH INNER AND OUTER BEARINGS DESTROYED. ALSO; LAST SEVERAL THREADS OF AXLE NUT DAMAGED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: A SUBSEQUENT HEARING (TO TACKLE THE SIT) WAS UNDERTAKEN WITH THE FAA; MANUFACTURER; AND COMPANY ENGINEERS. THE COMMITTEE DETERMINED THAT MECHANICALLY; EVERYTHING WAS ON AND IN PLACE. THE PROB STEMMED FROM THE FACT THAT THE FK10 GEAR DOES NOT HAVE A POSITIVE LOCK; EVEN AFTER THE LOCKING BOLTS ARE IN. RPTR STATES THAT ACFT SUCH AS THE DC9 AND THE B727 ARE DIFFERENT BECAUSE THEY DO HAVE A POSITIVE LOCK; THE BOLT CONTINUES THROUGH THE LOCKING NUT AND THE AXLE; AT THE SAME TIME. IT WAS DETERMINED THAT THE LOCKING BOLTS WERE NOT IN FAR ENOUGH; EVEN THOUGH THEY WERE TORQUED AS SPECIFIED. RPTR STATES THAT IN THE FUTURE; HE WOULD RATHER TAKE A CHANCE AT DAMAGING 2 BOLTS THAN HAVING A WHEEL COME OFF DURING TKOF. THERE HAVE BEEN APPROX 10 OTHER RELATED PROBS WITH THIS ACFT AND SINCE THIS INCIDENT; THE COMPANY MAINT PROCS HAVE BEEN LENGTHENED. NOW; THE NUMBER OF ROTATIONS AND THE NUMBER OF THREADS ARE COUNTED. ROTATIONS AND THREADS ARE REQUIRED TO MATCH; AND A MINIMUM MEASUREMENT THROUGH THE NUT MUST BE ACHIEVED BY THE USE OF A 'NO GO' GAUGE. SUPPLEMENTAL INFO FROM ACN 324623: ON TKOF; L LNDG MAIN GEAR LOST OUTER WHEEL. INFLT; DAMAGE WAS ASSESSED. FLC DID A LOW FLY-BY TWR FOR VISUAL CONFIRMATION; THEN BURNED OFF FUEL FOR LNDG. EMER WAS DECLARED. NORMAL LNDG WAS MADE. ACFT SUSTAINED NO OTHER DAMAGE. PAX AND CREW ARE FINE.