Narrative:

Previous write-ups were 'B' engine hydraulic switch replaced; borescope of both engines; no flts prior to maintenance. En route; 'B' hydraulic pressure light came on with no other indications; no master caution; etc. QRH was run; dispatch advised; contract maintenance was set up. Contract maintenance was standing by; worked on aircraft; and we departed. On approach into our arrival city; same light came on; and I noticed 'B' quantity of hydraulic fluid decreasing. Prior to any other lights or problem; we reviewed QRH procedures for 'B' system loss; ran all numbers for landing. On approach; fluid depleted; QRH procedures were run for 'B' system failure; flight attendants were notified of our situation. Landing was completed; aircraft was carefully taxied at a very slow pace until aircraft was clear of runway and shut down. We felt it would be safer to be towed to the gate. Passenger and flight attendants were informed we had an equipment problem; and to remain seated. We had equipment inspect aircraft to assure aircraft was safe. They found hydraulic fluid below right engine. Aircraft was then towed to the gate. Supplemental information from acn 780202: maintenance in our departing city svced the 'B' system hydraulic and tightened fittings and gave us all clear. In the descent going into ZZZ; 'B' system hydraulic quantity started to go down. I checked flaps 30 degrees and flaps 15 degrees landing speeds. Upon selecting flaps; I noticed 'B' system quantity was approaching 0 degrees; flaps came down to 10 degrees and slowly down to 15 degrees. I gave the first officer flaps 15 degrees; landing speeds; called for the trucks to roll; and contacted the flight attendants to let them know. We turned off and elected to shut down right there and had the trucks check out right engine. We tried to call the company to get a tug and tow. Radios would not work to contact the company at that point so we used cell phones. Talked to the passenger at least 3 times and still they used their cell phones to call headquarters to see why the fire trucks were there. One good point the flight attendants pointed out to us is that the first message to the passenger no one pays attention because they think it is a welcome passenger. Next time I will get their attention before I talk to them about the airplane with my voice.

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Original NASA ASRS Text

Title: B737 FLT CREW REPORTS MAINTENANCE ISSUES WITH HYD SYSTEM B DEPARTING TWO CITIES; CULMINATING IN SYSTEM FAILURE ON APPROACH. FLAP 15 LANDING ENSUES WITH TOW TO THE GATE.

Narrative: PREVIOUS WRITE-UPS WERE 'B' ENG HYD SWITCH REPLACED; BORESCOPE OF BOTH ENGS; NO FLTS PRIOR TO MAINT. ENRTE; 'B' HYD PRESSURE LIGHT CAME ON WITH NO OTHER INDICATIONS; NO MASTER CAUTION; ETC. QRH WAS RUN; DISPATCH ADVISED; CONTRACT MAINT WAS SET UP. CONTRACT MAINT WAS STANDING BY; WORKED ON ACFT; AND WE DEPARTED. ON APCH INTO OUR ARR CITY; SAME LIGHT CAME ON; AND I NOTICED 'B' QUANTITY OF HYD FLUID DECREASING. PRIOR TO ANY OTHER LIGHTS OR PROB; WE REVIEWED QRH PROCS FOR 'B' SYS LOSS; RAN ALL NUMBERS FOR LNDG. ON APCH; FLUID DEPLETED; QRH PROCS WERE RUN FOR 'B' SYS FAILURE; FLT ATTENDANTS WERE NOTIFIED OF OUR SITUATION. LNDG WAS COMPLETED; ACFT WAS CAREFULLY TAXIED AT A VERY SLOW PACE UNTIL ACFT WAS CLR OF RWY AND SHUT DOWN. WE FELT IT WOULD BE SAFER TO BE TOWED TO THE GATE. PAX AND FLT ATTENDANTS WERE INFORMED WE HAD AN EQUIP PROB; AND TO REMAIN SEATED. WE HAD EQUIP INSPECT ACFT TO ASSURE ACFT WAS SAFE. THEY FOUND HYD FLUID BELOW R ENG. ACFT WAS THEN TOWED TO THE GATE. SUPPLEMENTAL INFO FROM ACN 780202: MAINT IN OUR DEPARTING CITY SVCED THE 'B' SYS HYD AND TIGHTENED FITTINGS AND GAVE US ALL CLR. IN THE DSCNT GOING INTO ZZZ; 'B' SYS HYD QUANTITY STARTED TO GO DOWN. I CHKED FLAPS 30 DEGS AND FLAPS 15 DEGS LNDG SPDS. UPON SELECTING FLAPS; I NOTICED 'B' SYS QUANTITY WAS APCHING 0 DEGS; FLAPS CAME DOWN TO 10 DEGS AND SLOWLY DOWN TO 15 DEGS. I GAVE THE FO FLAPS 15 DEGS; LNDG SPDS; CALLED FOR THE TRUCKS TO ROLL; AND CONTACTED THE FLT ATTENDANTS TO LET THEM KNOW. WE TURNED OFF AND ELECTED TO SHUT DOWN RIGHT THERE AND HAD THE TRUCKS CHK OUT R ENG. WE TRIED TO CALL THE COMPANY TO GET A TUG AND TOW. RADIOS WOULD NOT WORK TO CONTACT THE COMPANY AT THAT POINT SO WE USED CELL PHONES. TALKED TO THE PAX AT LEAST 3 TIMES AND STILL THEY USED THEIR CELL PHONES TO CALL HEADQUARTERS TO SEE WHY THE FIRE TRUCKS WERE THERE. ONE GOOD POINT THE FLT ATTENDANTS POINTED OUT TO US IS THAT THE FIRST MESSAGE TO THE PAX NO ONE PAYS ATTN BECAUSE THEY THINK IT IS A WELCOME PAX. NEXT TIME I WILL GET THEIR ATTN BEFORE I TALK TO THEM ABOUT THE AIRPLANE WITH MY VOICE.

Data retrieved from NASA's ASRS site as of May 2009 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.