Narrative:

While taxiing out for takeoff we were performing the flight control check when the captain noticed that the lower rudder would not achieve full deflection to the right. In fact, only about 20 percent deflection to the right was achieved with full right pedal displacement from either seat. All hydraulic system were indicating normal with good pressure, all pumps on, and all engines running. We consulted the MEL which required a return to the gate and a visual inspection by qualified ground crew. We were met at the gate by maintenance personnel who visually confirmed full rudder deflection in both directions with no hydraulic leaks. Together we concluded that the flight control position indicator was malfunctioning, and we contacted our flight control dispatcher via radio. The dispatcher concurred and redispatched our flight according to MEL and company procedures. We again taxied out for takeoff and, upon receiving clearance, began our takeoff roll on runway 18L. On takeoff leg, after raising the gear handle, and at approximately 500 ft AGL with the copilot flying, we noted the hydraulic system 'a' low pressure lights illuminate. The flight engineer confirmed that system 'a' pressure was dropping as well as the quantity. They quickly both went to zero. We also noticed that the left and right main landing gears remained extended, but the nose gear had retracted. We then requested vectors for an extended right hand pattern to return for landing. The abnormal checklist for loss of hydraulic system 'a' was accomplished. The flaps were never retracted and remained at 15 degrees for landing as called for in the checklist. Nose gear was extended manually. An uneventful landing and rollout were accomplished. The aircraft cleared the runway using brakes and was brought to a stop. Emergency vehicles relayed to us that fluid was dripping out of the #7 leading edge slat area. The aircraft was shutdown and after cleared by maintenance was towed back to the gate with no further incident. Although no incident arose from this situation, we were concerned initially that there might be some connection between the rudder indication and the hydraulic failure. The lower rudder is pwred by hydraulic system 'a,' which is the system that subsequently failed, but the failure occurred at the leading edge slat area despite the fact that the flaps were never moved. The 2 failures appeared to be unrelated and we believed it to be coincidence. All maintenance, MEL, and dispatch procedures were completed as set out in our procedures.

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Original NASA ASRS Text

Title: LGT LOSES 'A' HYD SYS DURING INITIAL CLB FROM MCO. RETURN LAND.

Narrative: WHILE TAXIING OUT FOR TKOF WE WERE PERFORMING THE FLT CTL CHK WHEN THE CAPT NOTICED THAT THE LOWER RUDDER WOULD NOT ACHIEVE FULL DEFLECTION TO THE R. IN FACT, ONLY ABOUT 20 PERCENT DEFLECTION TO THE R WAS ACHIEVED WITH FULL R PEDAL DISPLACEMENT FROM EITHER SEAT. ALL HYD SYS WERE INDICATING NORMAL WITH GOOD PRESSURE, ALL PUMPS ON, AND ALL ENGS RUNNING. WE CONSULTED THE MEL WHICH REQUIRED A RETURN TO THE GATE AND A VISUAL INSPECTION BY QUALIFIED GND CREW. WE WERE MET AT THE GATE BY MAINT PERSONNEL WHO VISUALLY CONFIRMED FULL RUDDER DEFLECTION IN BOTH DIRECTIONS WITH NO HYD LEAKS. TOGETHER WE CONCLUDED THAT THE FLT CTL POS INDICATOR WAS MALFUNCTIONING, AND WE CONTACTED OUR FLT CTL DISPATCHER VIA RADIO. THE DISPATCHER CONCURRED AND REDISPATCHED OUR FLT ACCORDING TO MEL AND COMPANY PROCS. WE AGAIN TAXIED OUT FOR TKOF AND, UPON RECEIVING CLRNC, BEGAN OUR TKOF ROLL ON RWY 18L. ON TKOF LEG, AFTER RAISING THE GEAR HANDLE, AND AT APPROX 500 FT AGL WITH THE COPLT FLYING, WE NOTED THE HYD SYS 'A' LOW PRESSURE LIGHTS ILLUMINATE. THE FE CONFIRMED THAT SYS 'A' PRESSURE WAS DROPPING AS WELL AS THE QUANTITY. THEY QUICKLY BOTH WENT TO ZERO. WE ALSO NOTICED THAT THE L AND R MAIN LNDG GEARS REMAINED EXTENDED, BUT THE NOSE GEAR HAD RETRACTED. WE THEN REQUESTED VECTORS FOR AN EXTENDED R HAND PATTERN TO RETURN FOR LNDG. THE ABNORMAL CHKLIST FOR LOSS OF HYD SYS 'A' WAS ACCOMPLISHED. THE FLAPS WERE NEVER RETRACTED AND REMAINED AT 15 DEGS FOR LNDG AS CALLED FOR IN THE CHKLIST. NOSE GEAR WAS EXTENDED MANUALLY. AN UNEVENTFUL LNDG AND ROLLOUT WERE ACCOMPLISHED. THE ACFT CLRED THE RWY USING BRAKES AND WAS BROUGHT TO A STOP. EMER VEHICLES RELAYED TO US THAT FLUID WAS DRIPPING OUT OF THE #7 LEADING EDGE SLAT AREA. THE ACFT WAS SHUTDOWN AND AFTER CLRED BY MAINT WAS TOWED BACK TO THE GATE WITH NO FURTHER INCIDENT. ALTHOUGH NO INCIDENT AROSE FROM THIS SIT, WE WERE CONCERNED INITIALLY THAT THERE MIGHT BE SOME CONNECTION BTWN THE RUDDER INDICATION AND THE HYD FAILURE. THE LOWER RUDDER IS PWRED BY HYD SYS 'A,' WHICH IS THE SYS THAT SUBSEQUENTLY FAILED, BUT THE FAILURE OCCURRED AT THE LEADING EDGE SLAT AREA DESPITE THE FACT THAT THE FLAPS WERE NEVER MOVED. THE 2 FAILURES APPEARED TO BE UNRELATED AND WE BELIEVED IT TO BE COINCIDENCE. ALL MAINT, MEL, AND DISPATCH PROCS WERE COMPLETED AS SET OUT IN OUR PROCS.

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.