ACFT EQUIP PROB MALFUNCTION MANDATES A RETURN LAND.

Narrative

WE DEPARTED BWI WITH THE ANTI-SKID SYS ON MEL (SYS INOP). JUST AFTER GEAR RETRACTION; TWR CALLED US AND TOLD US WE HAD LOST A WHEEL ON TKOF. THERE WERE NO INDICATIONS OF A PROB IN THE COCKPIT. I REQUESTED CLRNC TO HOLD AT 3000 FT WHILE WE ANALYZED THE PROB; AND INDICATED WE WERE DECLARING AN EMER AND WOULD BE RETURNING TO BWI. I ALSO ASKED FOR ALL INFO AVAILABLE AS TO WHAT PIECES AND/OR PARTS WERE ON THE RWY. I NOTIFIED COMPANY OF OUR PROBS AND INTENTIONS AND REQUESTED MAINT INFO ABOUT THE WHEEL AND ANY OTHER PARTS WHEN FOUND. I INFORMED THE PAX AND REQUESTED LEAD FLT ATTENDANT TO RPT TO THE COCKPIT WHERE WE DISCUSSED OUR PROB AND I INDICATED WHAT ACTIONS I WANTED THE FLT ATTENDANTS TO TAKE; INCLUDING PAX BRIEFINGS; STOWAGE OF ITEMS; REVIEW OF EMER LNDG AND EVAC; AND SPECIAL BRIEFING OF PAX NEAR EMER EXITS. AT THIS TIME; THE COPLT AND I REVIEWED THE ACFT HANDBOOK FOR INFO RELATING TO THE LOSS OF A WHEEL. THERE WAS NONE. WE REVIEWED SEVERAL SECTIONS DEALING WITH GEAR PROBS ON LNDG AND THEN REVIEWED THE EMER EVAC PROCS. THE RWY SWEEP TURNED UP NO MISSING PARTS; AND THE WHEEL WAS RECOVERED FROM A WOODED AREA AND EXAMINED BY OUR MAINT PEOPLE. I WAS TOLD THE WHEEL APPEARED TO BE THE R OUTBOARD MAIN GEAR WHEEL AND IT APPEARED TO BE A CLEAN SEPARATION. I THEN LOWERED THE GEAR (NORMAL INDICATIONS) AND SENT THE COPLT BACK TO LOOK THROUGH THE GEAR VIEWING LENS. HIS RPT WAS THE REMAINING WHEEL LOOKED NORMAL AND THAT HE COULD SEE NO OBVIOUS OTHER DAMAGE. WE WERE READY AND THE CABIN TEAM RPTED READY; SO WE COMMENCED ON APCH TO RWY 33 AT BWI. CLR SKY; CLEAN AND DRY RWY; WIND FAVORABLE AT 10 KTS. AT THE OM; THE 'B' HYD SYS FAILED. I EXECUTED A MISSED APCH AND THEN WENT THROUGH THE PROCS AND CHKLISTS FOR 'B' HYD FAILURE. WE THEN INITIATED ANOTHER APCH. THE TOUCHDOWN WAS SMOOTH AND I USED MINIMUM BRAKING AND REVERSE THRUST TO SLOW THE ACFT. WE EXITED THE RWY ON A TXWY ABOUT 7000 FT DOWN THE RWY; PARKED THE ACFT AND SHUT DOWN THE ENGS. THE CRASH RESCUE TEAM TOLD US NO FIRE OR SMOKE AND OTHERWISE OK. I TOLD THE PAX EVERYTHING WAS SAFE AND THAT THEY WOULD SHORTLY DEPLANE USING PORTABLE STAIRS AND RETURN TO THE TERMINAL IN A BUS. POST INCIDENT ANALYSIS INDICATED THE MAIN WHEEL BEARING HAD FAILED (WHEEL WAS INSTALLED 1 WK PRIOR). THE HYD FAILURE WAS UNRELATED AND RESULTED FROM A LINE BEING CHAFED BY A CLAMP. I'VE HEARD OF SEVERAL INSTANCES OF WHEEL LOSS. I DON'T KNOW HOW OFTEN THIS HAPPENS; BUT IT SEEMS AS IF WE SHOULD HAVE SOME INFO IN THE HANDBOOK; AND SHOULD HAVE SOME INDICATION IN THE COCKPIT AS TO LNDG GEAR WHEEL INFLATION STATUS. I KNOW SOME ACFT DO HAVE AN INFLATION/TEMP MONITORING SYS. PERHAPS SOME RESEARCH SHOULD BE DONE AS TO THE FEASIBILITY OF INSTALLING A MONITOR SYS ON ALL TRANSPORT CATEGORY ACFT.