Narrative:

Received aircraft under fifo conditions with same 'system a quantity low' write-up 2 days in a row. Logbook signoffs indicated the fix was to fill hydraulic fluid to full. I crosschecked the quantity gauge and it was at 3 gals. I asked maintenance to pressurize the hydraulic system and check for leaks. Maintenance said he could not find a leak but tightened a thrust reverser line removing a panel on the top of the #2 engine and then filled the fluid to 'full' (the mechanics seemed to go right to that area). I confirmed the system a quantity at 'full' and maintenance cleared the write-up. Flight was mostly uneventful and I carefully monitored the a hydraulic quantity gauge and hydraulic system in general. On final approach with flaps at 30 degrees and gear down I became concerned again when the 'a' system hydraulic quantity gauge was at the 'refill' line. We called for a maintenance and he began to troubleshoot. When the maintenance removed the #2 engine cowling I witnessed an eye catching amount of red hydraulic fluid spillout that had pooled in the cowling. During the troubleshooting when I was in the ramp office; my less than 100 hour copilot had been putting out the flaps and assisting the maintenance with his job. He was about to lift the landing gear lever up when I walked into the flight deck and told him not to touch the gear handle. I informed the copilot and the maintenance that we do not perform those functions (got the frustrated stink eye from the mechanic). I called the company to confirm the procedure for non normal functions which a pilot could assist the maintenance with. The maintenance performed all maintenance functions I would not assist with thereafter. After some time and some phone calls the maintenance informed me he could not find a leak in thrust reverser and that he could just MEL the thrust reverser and fill up the fluid again. I informed him that I was not comfortable with the decision and I called maintenance at maintenance control and talked to him directly. He suggested an engine #2 start and engine run and I concurred. Immediately upon commencing the engine start the maintenance was able to confirm that there was a leak in the #2 thrust reverser return line from a high inboard side panel which he had removed. We MEL'ed and secured the #2 thrust reverser and flew back. After landing they took the aircraft away and gave me another ship for my next flight. There was a computer flag in view on my ADI. I turned the flight director on and off; tapped the window and checked circuit breakers. The first officer told me the previous first officer briefed him that they were having some 'computer' problems with regard to the flag. I decided to do my normal overhead; instrument panel; and central console check. The flag still remained and we called maintenance for a radio technician. I left the flight deck so the 2 men could work. They replaced the ADI and still got the flag. One (the lead radio mechanic?) man left for quite some time and I was told that he was going around to other airplanes to look for 'something.' when he returned he went into the flight deck and came out saying it was fixed and that the standby power switch had been in battery. I do not remember seeing the guard open on my scan. Both radio technicians and the first officer were in the flight deck for quite some time (at least 20 mins) and none of them noticed the switch position. I do not know if the previous crew; who flew the aircraft before us missed replacing the switch in the proper position after a standby power check on the initial preflight and continued to fly anyway. The write-off was cleared and we went without incident.

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Original NASA ASRS Text

Title: A B737-200 CAPT RPTS POOR MAINT ACTION ON A CHRONIC 'A' SYS HYD LEAK REQUIRING CONTINUOUS SVCING. SIGNOFFS WERE SVCED 'A' SYS RESERVOIR.

Narrative: RECEIVED ACFT UNDER FIFO CONDITIONS WITH SAME 'SYS A QUANTITY LOW' WRITE-UP 2 DAYS IN A ROW. LOGBOOK SIGNOFFS INDICATED THE FIX WAS TO FILL HYD FLUID TO FULL. I XCHKED THE QUANTITY GAUGE AND IT WAS AT 3 GALS. I ASKED MAINT TO PRESSURIZE THE HYD SYS AND CHK FOR LEAKS. MAINT SAID HE COULD NOT FIND A LEAK BUT TIGHTENED A THRUST REVERSER LINE REMOVING A PANEL ON THE TOP OF THE #2 ENG AND THEN FILLED THE FLUID TO 'FULL' (THE MECHS SEEMED TO GO RIGHT TO THAT AREA). I CONFIRMED THE SYS A QUANTITY AT 'FULL' AND MAINT CLRED THE WRITE-UP. FLT WAS MOSTLY UNEVENTFUL AND I CAREFULLY MONITORED THE A HYD QUANTITY GAUGE AND HYD SYS IN GENERAL. ON FINAL APCH WITH FLAPS AT 30 DEGS AND GEAR DOWN I BECAME CONCERNED AGAIN WHEN THE 'A' SYS HYD QUANTITY GAUGE WAS AT THE 'REFILL' LINE. WE CALLED FOR A MAINT AND HE BEGAN TO TROUBLESHOOT. WHEN THE MAINT REMOVED THE #2 ENG COWLING I WITNESSED AN EYE CATCHING AMOUNT OF RED HYD FLUID SPILLOUT THAT HAD POOLED IN THE COWLING. DURING THE TROUBLESHOOTING WHEN I WAS IN THE RAMP OFFICE; MY LESS THAN 100 HR COPLT HAD BEEN PUTTING OUT THE FLAPS AND ASSISTING THE MAINT WITH HIS JOB. HE WAS ABOUT TO LIFT THE LNDG GEAR LEVER UP WHEN I WALKED INTO THE FLT DECK AND TOLD HIM NOT TO TOUCH THE GEAR HANDLE. I INFORMED THE COPLT AND THE MAINT THAT WE DO NOT PERFORM THOSE FUNCTIONS (GOT THE FRUSTRATED STINK EYE FROM THE MECH). I CALLED THE COMPANY TO CONFIRM THE PROC FOR NON NORMAL FUNCTIONS WHICH A PLT COULD ASSIST THE MAINT WITH. THE MAINT PERFORMED ALL MAINT FUNCTIONS I WOULD NOT ASSIST WITH THEREAFTER. AFTER SOME TIME AND SOME PHONE CALLS THE MAINT INFORMED ME HE COULD NOT FIND A LEAK IN THRUST REVERSER AND THAT HE COULD JUST MEL THE THRUST REVERSER AND FILL UP THE FLUID AGAIN. I INFORMED HIM THAT I WAS NOT COMFORTABLE WITH THE DECISION AND I CALLED MAINT AT MAINT CTL AND TALKED TO HIM DIRECTLY. HE SUGGESTED AN ENG #2 START AND ENG RUN AND I CONCURRED. IMMEDIATELY UPON COMMENCING THE ENG START THE MAINT WAS ABLE TO CONFIRM THAT THERE WAS A LEAK IN THE #2 THRUST REVERSER RETURN LINE FROM A HIGH INBOARD SIDE PANEL WHICH HE HAD REMOVED. WE MEL'ED AND SECURED THE #2 THRUST REVERSER AND FLEW BACK. AFTER LNDG THEY TOOK THE ACFT AWAY AND GAVE ME ANOTHER SHIP FOR MY NEXT FLT. THERE WAS A COMPUTER FLAG IN VIEW ON MY ADI. I TURNED THE FLT DIRECTOR ON AND OFF; TAPPED THE WINDOW AND CHKED CIRCUIT BREAKERS. THE FO TOLD ME THE PREVIOUS FO BRIEFED HIM THAT THEY WERE HAVING SOME 'COMPUTER' PROBS WITH REGARD TO THE FLAG. I DECIDED TO DO MY NORMAL OVERHEAD; INST PANEL; AND CENTRAL CONSOLE CHK. THE FLAG STILL REMAINED AND WE CALLED MAINT FOR A RADIO TECHNICIAN. I LEFT THE FLT DECK SO THE 2 MEN COULD WORK. THEY REPLACED THE ADI AND STILL GOT THE FLAG. ONE (THE LEAD RADIO MECH?) MAN LEFT FOR QUITE SOME TIME AND I WAS TOLD THAT HE WAS GOING AROUND TO OTHER AIRPLANES TO LOOK FOR 'SOMETHING.' WHEN HE RETURNED HE WENT INTO THE FLT DECK AND CAME OUT SAYING IT WAS FIXED AND THAT THE STANDBY PWR SWITCH HAD BEEN IN BATTERY. I DO NOT REMEMBER SEEING THE GUARD OPEN ON MY SCAN. BOTH RADIO TECHNICIANS AND THE FO WERE IN THE FLT DECK FOR QUITE SOME TIME (AT LEAST 20 MINS) AND NONE OF THEM NOTICED THE SWITCH POS. I DO NOT KNOW IF THE PREVIOUS CREW; WHO FLEW THE ACFT BEFORE US MISSED REPLACING THE SWITCH IN THE PROPER POS AFTER A STANDBY PWR CHK ON THE INITIAL PREFLT AND CONTINUED TO FLY ANYWAY. THE WRITE-OFF WAS CLRED AND WE WENT WITHOUT INCIDENT.

Data retrieved from NASA's ASRS site as of January 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.