Narrative:

Aircraft X had a PIREP of noise from aft lavatories. This maintenance person found the lavatory blower motor faulted. This was then put on placard in accordance with MEL. The procedure to placard this inoperative; was to pull and collar applicable circuit breakers of the inoperative blower motors. No location is given to accomplish this procedure. While troubleshooting the problem; of lavatory toilets not flushing; it was found that the vacuum waste control circuit breaker was pulled and collared. The circuit breakers for the vacuum waste blower is located behind the P91 panel. This was also pulled and collared. While referencing wdm and ssm; it was found that if the control breaker is pulled; this will inoperative all 3 lavatory toilets to not flush. The reason for aircraft X to make it a 'fix before departure' was due to the lavatories not flushing. The MEL should have the procedure state that the vacuum waste blower for the B737; circuit breaker give a location; and number. Reference ssm. Vacuum toilet blower motor was improperly deactivated. Not enough information was provided when inoperative the blowers. The wrong circuit breaker was pulled to inoperative the waste vacuum blower. Supplemental information from acn 800128: the MEL is not specific as to the breakers that need to be pulled. Reference wiring diagram; vacuum waste control C1388 is on P-91 panel location C-11 (breaker pulled) this is the obvious breaker to pull and vacuum waste blower C1389 location. F2 is located inside P-91 panel (breaker pulled). Both breakers were pulled due to the reference is not specific as to the location of the breakers and does not state how many breakers to pull. The MEL is not aircraft specific. It is for B737 and B767 and should state pull vacuum waste blower circuit breaker located inside P-91 panel; location F2. Not vacuum waste control on P-91 panel. This should be made an MEL with maintenance procedures and state circuit breakers and locations. There are no specific numbers for circuit breakers to be pulled in the MEL. The obvious circuit breaker is the vacuum waste control on the P-91 panel.

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Original NASA ASRS Text

Title: TWO MECHANICS REPORT THE AFT LAV VACUUM TOILET BLOWER MOTOR WAS IMPROPERLY DEACTIVATED ON A B737-800. CABIN MAINT PROCEDURES MANUAL SHOULD STATE TO PULL THE VACUUM WASTE BLOWER CIRCUIT BREAKER INSIDE P-91 PANEL.

Narrative: ACFT X HAD A PIREP OF NOISE FROM AFT LAVATORIES. THIS MAINT PERSON FOUND THE LAVATORY BLOWER MOTOR FAULTED. THIS WAS THEN PUT ON PLACARD IN ACCORDANCE WITH MEL. THE PROC TO PLACARD THIS INOP; WAS TO PULL AND COLLAR APPLICABLE CIRCUIT BREAKERS OF THE INOPERATIVE BLOWER MOTORS. NO LOCATION IS GIVEN TO ACCOMPLISH THIS PROC. WHILE TROUBLESHOOTING THE PROB; OF LAVATORY TOILETS NOT FLUSHING; IT WAS FOUND THAT THE VACUUM WASTE CTL CIRCUIT BREAKER WAS PULLED AND COLLARED. THE CIRCUIT BREAKERS FOR THE VACUUM WASTE BLOWER IS LOCATED BEHIND THE P91 PANEL. THIS WAS ALSO PULLED AND COLLARED. WHILE REFING WDM AND SSM; IT WAS FOUND THAT IF THE CTL BREAKER IS PULLED; THIS WILL INOP ALL 3 LAVATORY TOILETS TO NOT FLUSH. THE REASON FOR ACFT X TO MAKE IT A 'FIX BEFORE DEP' WAS DUE TO THE LAVATORIES NOT FLUSHING. THE MEL SHOULD HAVE THE PROC STATE THAT THE VACUUM WASTE BLOWER FOR THE B737; CIRCUIT BREAKER GIVE A LOCATION; AND NUMBER. REF SSM. VACUUM TOILET BLOWER MOTOR WAS IMPROPERLY DEACTIVATED. NOT ENOUGH INFO WAS PROVIDED WHEN INOP THE BLOWERS. THE WRONG CIRCUIT BREAKER WAS PULLED TO INOP THE WASTE VACUUM BLOWER. SUPPLEMENTAL INFO FROM ACN 800128: THE MEL IS NOT SPECIFIC AS TO THE BREAKERS THAT NEED TO BE PULLED. REF WIRING DIAGRAM; VACUUM WASTE CTL C1388 IS ON P-91 PANEL LOCATION C-11 (BREAKER PULLED) THIS IS THE OBVIOUS BREAKER TO PULL AND VACUUM WASTE BLOWER C1389 LOCATION. F2 IS LOCATED INSIDE P-91 PANEL (BREAKER PULLED). BOTH BREAKERS WERE PULLED DUE TO THE REF IS NOT SPECIFIC AS TO THE LOCATION OF THE BREAKERS AND DOES NOT STATE HOW MANY BREAKERS TO PULL. THE MEL IS NOT ACFT SPECIFIC. IT IS FOR B737 AND B767 AND SHOULD STATE PULL VACUUM WASTE BLOWER CIRCUIT BREAKER LOCATED INSIDE P-91 PANEL; LOCATION F2. NOT VACUUM WASTE CTL ON P-91 PANEL. THIS SHOULD BE MADE AN MEL WITH MAINT PROCS AND STATE CIRCUIT BREAKERS AND LOCATIONS. THERE ARE NO SPECIFIC NUMBERS FOR CIRCUIT BREAKERS TO BE PULLED IN THE MEL. THE OBVIOUS CIRCUIT BREAKER IS THE VACUUM WASTE CTL ON THE P-91 PANEL.

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.