Narrative:

Aft right lavatory was deferred for this flight and had been deferred inoperative 2 days prior to this flight. During the maintenance release document and MEL deferred items review; I checked to verify that the item was properly deferred. I found an incorrect circuit breaker pulled and collared for this deferral. The lavatory flush motor at P18-4; B3 was supposed to be collared; but the circuit breaker at P18-4; A7 was the one collared. I notified dispatch; maintenance and ZZZ station maintenance. ZZZ maintenance corrected the error before we departed. It appears to me that the airplane flew for 2 days without the proper deferral procedures accomplished by maintenance; and no pilot in 2 days found the error.

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Original NASA ASRS Text

Title: A B737-300 CAPT RPTS IMPROPER DEFERRAL OF THE R LAVATORY. INCORRECT CIRCUIT BREAKERS PULLED AND COLLARED. ACFT OPERATED 2 DAYS BEFORE DISCOVERY.

Narrative: AFT R LAVATORY WAS DEFERRED FOR THIS FLT AND HAD BEEN DEFERRED INOP 2 DAYS PRIOR TO THIS FLT. DURING THE MAINT RELEASE DOCUMENT AND MEL DEFERRED ITEMS REVIEW; I CHKED TO VERIFY THAT THE ITEM WAS PROPERLY DEFERRED. I FOUND AN INCORRECT CIRCUIT BREAKER PULLED AND COLLARED FOR THIS DEFERRAL. THE LAVATORY FLUSH MOTOR AT P18-4; B3 WAS SUPPOSED TO BE COLLARED; BUT THE CIRCUIT BREAKER AT P18-4; A7 WAS THE ONE COLLARED. I NOTIFIED DISPATCH; MAINT AND ZZZ STATION MAINT. ZZZ MAINT CORRECTED THE ERROR BEFORE WE DEPARTED. IT APPEARS TO ME THAT THE AIRPLANE FLEW FOR 2 DAYS WITHOUT THE PROPER DEFERRAL PROCS ACCOMPLISHED BY MAINT; AND NO PLT IN 2 DAYS FOUND THE ERROR.

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.