LOSS OF HYDS AFTER TKOF. RETURN LAND.

Narrative

IMPROVED FLAPS 1 TKOF FROM DEN ARPT RWY 35R. 62 DEGS F CALM WINDS. AT ROTATION; L MAIN INBOARD TIRE TREAD SEPARATED AND BROKE ON 'A' HYD LINE CAUSING THE LOSS OF 'A' SYS. ELECTED TO HOLD AND BURN FUEL TO GET LNDG WT DOWN. HELD APPROX 45 MINS WHEN 'B' SYS STARTED TO DROP. RETURNED TO DEN RWY 35R AND LANDED. UNEVENTFUL LNDG/ROLLOUT. FIRE TRUCKS WERE IN POS ON TXWY. TAXIED ACFT OFF RWY ON Z10 AND REMOVED PAX BY PORTABLE STAIRS TO BUS THEM BACK TO TERMINAL. DID NOT WANT TO TAKE A CHANCE TAXIING WITH AIRPLANE CONDITION. ONE THING THAT MIGHT HELP TO PREVENT THIS WOULD BE IF WE HAD THE HIGH THRUST ENGS ON ALL OUR FLEET. WE WOULD NOT HAVE TO DO AS MANY IMPROVED FLAPS 1 TKOFS. THIS MANEUVER REQUIRES US TO ADD QUITE A BIT OF EXTRA SPD TO OUR TKOF NUMBERS. THE ATC SYS WORKED VERY WELL. WE RECEIVED ALL THE ASSISTANCE WE REQUESTED VERY PROMPTLY AND COURTEOUSLY. SUPPLEMENTAL INFO FROM ACN 267605: ATC INFORMED US OF TIRE TREAD ON RWY. OUR MAINT DETERMINED IT WAS FROM OUR MAIN LNDG GEAR. ELECTED TO PREPARE CABIN FOR POSSIBLE EVAC. RETURNED TO DEN 3000 LBS OVER MAX LNDG WT. HAD EMER EQUIP PERSONNEL LOOK FOR FIRE; NONE RPTED. WE HAD TO DO IMPROVED FLAP TKOF AT 62 DEGS F BECAUSE OF D-RATED ENGS. THIS REQUIRES A MUCH HIGHER ROTATION SPD THAN NORMAL. THIS HIGHER SPD ROTATION MAY HAVE CAUSED THE TIRE TREAD TO SHRED. THE TIRE PUNCTURED 1 'A' HYD LINE AND CAUSED OTHER DAMAGE. ADDITIONALLY; PRIOR TO TKOF; WE HAD TAXIED FROM RAMP AREA TO RWY 35R. THIS LONG TAXI MAY HAVE HEATED BRAKES OR TIRE; WHICH MAY HAVE AGGRAVATED THE ABOVE PROB.