Narrative:

During descent into gso I noticed that the right hydraulic pump pressure was zero, left pump pressure was normal. Main and emergency accumulator pressure was normal. During final approach segment flaps were selected to 10 degrees, at which point the left pump pressure dropped to zero. We selected gear down and only the nose gear showed down and locked. Hydraulic pumps were cavitating at this time and emergency and main pressure indications remained normal. We began missed approach procedures. Advised ATC, declared an emergency, even though we did not feel it was an emergency. At this time we complied with all checklist items and our QRH guidelines for hydraulic pressure/pump failures. Returned to gso and landed uneventfully. Stopped the aircraft on runway 5 to check handling. Aircraft performed normal so we cleared the active runway and stopped on the taxiway, completed after landing checklist and again checked aircraft to see if we could continue to taxi. Aircraft handled well so we proceed to the ramp and shut down the aircraft, deplaned the passenger. Callback conversation with reporter revealed the following information: initially, pump failure was suspected so this is why flight crew continued to operate flaps (BA32 emergency hydraulic system does not allow flap retraction). After emergency declared, tower handled all communications with emergency response team. A tug was not available at this station, and aircraft arrival at gate coincided with accumulator depletion. Follow-up with maintenance revealed chafing in right landing gear bay door hydraulic line which caused system leak.

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Original NASA ASRS Text

Title: PART 135 BA32 FLC EXPERIENCED HYD FAILURE DURING APCH. MISSED APCH AND DECLARED EMER.

Narrative: DURING DSCNT INTO GSO I NOTICED THAT THE R HYD PUMP PRESSURE WAS ZERO, L PUMP PRESSURE WAS NORMAL. MAIN AND EMER ACCUMULATOR PRESSURE WAS NORMAL. DURING FINAL APCH SEGMENT FLAPS WERE SELECTED TO 10 DEGS, AT WHICH POINT THE L PUMP PRESSURE DROPPED TO ZERO. WE SELECTED GEAR DOWN AND ONLY THE NOSE GEAR SHOWED DOWN AND LOCKED. HYD PUMPS WERE CAVITATING AT THIS TIME AND EMER AND MAIN PRESSURE INDICATIONS REMAINED NORMAL. WE BEGAN MISSED APCH PROCS. ADVISED ATC, DECLARED AN EMER, EVEN THOUGH WE DID NOT FEEL IT WAS AN EMER. AT THIS TIME WE COMPLIED WITH ALL CHKLIST ITEMS AND OUR QRH GUIDELINES FOR HYD PRESSURE/PUMP FAILURES. RETURNED TO GSO AND LANDED UNEVENTFULLY. STOPPED THE ACFT ON RWY 5 TO CHK HANDLING. ACFT PERFORMED NORMAL SO WE CLRED THE ACTIVE RWY AND STOPPED ON THE TXWY, COMPLETED AFTER LNDG CHKLIST AND AGAIN CHKED ACFT TO SEE IF WE COULD CONTINUE TO TAXI. ACFT HANDLED WELL SO WE PROCEED TO THE RAMP AND SHUT DOWN THE ACFT, DEPLANED THE PAX. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: INITIALLY, PUMP FAILURE WAS SUSPECTED SO THIS IS WHY FLC CONTINUED TO OPERATE FLAPS (BA32 EMER HYD SYS DOES NOT ALLOW FLAP RETRACTION). AFTER EMER DECLARED, TWR HANDLED ALL COMS WITH EMER RESPONSE TEAM. A TUG WAS NOT AVAILABLE AT THIS STATION, AND ACFT ARR AT GATE COINCIDED WITH ACCUMULATOR DEPLETION. FOLLOW-UP WITH MAINT REVEALED CHAFING IN R LNDG GEAR BAY DOOR HYD LINE WHICH CAUSED SYS LEAK.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.