Narrative:

Aircraft had #2 engine B fire loop deferred. Except for the first flight of the day; it is not a requirement to do a fire test; however as a precautionary measure I elected to verify the remaining system was still functioning. I discovered both loops to be inoperative and contacted maintenance to discover this is a chronic item and the log history indicated 499 hours of problems. As a captain and safety advocate; I find this to be unacceptable and another example of the company's reactive maintenance process. After resetting the circuit breaker and cycling the system selector switch several times; the a loop returned to normal operating status. Maintenance elected to sign off the aircraft after we tested and retested the system many times; ensuring that it was functioning properly. We operated the flight 1.5 hours late; with the agreement the airplane would be removed from service and repaired once and for all. As another safety measure; I elected to place our jump seater in a window seat next to the #2 engine; to act as an observer. I am concerned with our current maintenance procedures and the fact the MEL does not require the remaining fire system to be tested prior to each departure; knowing 1 loop is already deferred.

Related reports:

Google
 

Original NASA ASRS Text

Title: B737-500 WAS DISPATCHED WITH ONE ENG FIRE LOOP DEFERRED. CAPT DISCOVERED THAT OTHER LOOP WAS ALSO INOP.

Narrative: ACFT HAD #2 ENG B FIRE LOOP DEFERRED. EXCEPT FOR THE FIRST FLT OF THE DAY; IT IS NOT A REQUIREMENT TO DO A FIRE TEST; HOWEVER AS A PRECAUTIONARY MEASURE I ELECTED TO VERIFY THE REMAINING SYS WAS STILL FUNCTIONING. I DISCOVERED BOTH LOOPS TO BE INOP AND CONTACTED MAINT TO DISCOVER THIS IS A CHRONIC ITEM AND THE LOG HISTORY INDICATED 499 HRS OF PROBS. AS A CAPT AND SAFETY ADVOCATE; I FIND THIS TO BE UNACCEPTABLE AND ANOTHER EXAMPLE OF THE COMPANY'S REACTIVE MAINT PROCESS. AFTER RESETTING THE CIRCUIT BREAKER AND CYCLING THE SYS SELECTOR SWITCH SEVERAL TIMES; THE A LOOP RETURNED TO NORMAL OPERATING STATUS. MAINT ELECTED TO SIGN OFF THE ACFT AFTER WE TESTED AND RETESTED THE SYS MANY TIMES; ENSURING THAT IT WAS FUNCTIONING PROPERLY. WE OPERATED THE FLT 1.5 HRS LATE; WITH THE AGREEMENT THE AIRPLANE WOULD BE REMOVED FROM SVC AND REPAIRED ONCE AND FOR ALL. AS ANOTHER SAFETY MEASURE; I ELECTED TO PLACE OUR JUMP SEATER IN A WINDOW SEAT NEXT TO THE #2 ENG; TO ACT AS AN OBSERVER. I AM CONCERNED WITH OUR CURRENT MAINT PROCS AND THE FACT THE MEL DOES NOT REQUIRE THE REMAINING FIRE SYS TO BE TESTED PRIOR TO EACH DEP; KNOWING 1 LOOP IS ALREADY DEFERRED.

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.