LEAR 31A FLC HAS HYD FAILURE DURING LNDG GEAR EXTENSION.

Narrative

AFTER INTERCEPTING THE ILS RWY 28 AT AGC; THE CREW OBSERVED INDICATIONS OF A HYD SYS FAILURE AFTER 'GEAR DOWN' WAS SELECTED. HYD SYS PRESSURE READ NEAR ZERO AND 2 RED 'UNSAFE' LIGHTS ACCOMPANIED THE NORMAL 3 GREEN LIGHTS INDICATING THAT THE GEAR WAS DOWN AND LOCKED AND THAT THE MAIN GEAR DOORS WERE OUT OF POS. CREW DECLARED AN EMER AND WAS HANDED OFF TO PITTSBURGH APCH. CREW REQUESTED 15 MINS OF DELAY VECTORS TO COMPLETE APPROPRIATE CHKLISTS; BRIEF PAX AND PREPARE FOR APCH AND LNDG. CREW ALSO REQUESTED RWY 18L AT PIT (11500 FT LONG);EMER EQUIP TO STAND BY AND TOWING SVC TO THE FBO. AFTER COMPLETING ABNORMAL CHKLISTS RELATING TO HYD FAILURE AND LNDG; CREW BRIEFED LEAD PAX REGARDING THE SIT. PAX APPEARED ANXIOUS; BUT SATISFIED WITH THE BRIEF AND WAS ADVISED TO PREPARE THE OTHER PAX (HIS WIFE AND CHILD) FOR THE ARR AT PIT. MUTUALLY AGREEING THAT THEY WERE PREPARED; THE CREW ADVISED APCH THAT THEY WERE READY TO PROCEED INBOUND ON THE ILS RWY 28L APCH TO PIT. A VECTOR WAS PROVIDED AND THE ACFT INTERCEPTED THE COURSE AT 12 NM FROM THE RWY. THE RWY WAS IN SIGHT FOR THE REMAINDER OF THE FLT AND AT ROUGHLY 8 NM; THE ACFT WAS CLRED FOR THE VISUAL APCH TO RWY 28L AT PIT. FROM THIS POINT UNTIL SHORT FINAL; THE FLT WAS UNEVENTFUL. AT ABOUT 200 FT AGL; THE STANDBY HYD PUMP WAS SELECTED ON; AND HYD SYS PRESSURE RETURNED TO THE RATED PRESSURE OF THE STANDBY PUMP. TOUCHDOWN WAS AT VREF AND NORMAL BRAKING WAS USED. HYD SYS PRESSURE WAS SUSTAINED AND A NORMAL ROLLOUT RESULTED. THRUST REVERSERS WERE NOT USED AS THE THRUST REVERSER SYS WAS PREVIOUSLY MEL'ED AND INOP'ED FOR THIS FLT. THE ACFT CAME TO A STOP ON THE CTRLINE ABOUT 3000 FT FROM THE APCH END OF RWY 28L. FIRE EQUIP HAD RESPONDED AND WRE IN POS AROUND THE ACFT. NORMAL SHUTDOWN PROCS WERE USED AND AN EXTERIOR INSPECTION UNDERTAKEN. RED HYD FLUID WAS EVIDENT ON THE REAR OF THE ACFT AND R FLAP; INDICATING THAT THE LEAK ORIGINATED ON THE R MAIN LNDG GEAR STRUCTURE. THE PREFLT INSPECTION OF THE ACFT PROVIDED NO INDICATION OF TROUBLE ON ANY OF THE ACFT SYS AND IN THIS REGARD THE CREW WOULD HAVE NO WAY OF KNOWING OF ANY IMMINENT SYS FAILURES. HOWEVER; BEING VIGILANT DURING THOROUGH PRE- AND POSTFLT INSPECTIONS FOR ANY INDICATION OF PROBS IS KEY AT KEEPING FAILURES LIKE THIS ONE TO A MINIMUM.