A B737-800's lavatory vacuum motor worked poorly on the ground. A contract mechanic applied the MEL ...

Narrative:

Shortly before departure; we were notified by the flight attendants that all three lavatories were inoperative. After further investigation; we realized that the lavatories would flush but without much suction. Contract maintenance was notified and the troubleshooting began. Ultimately; maintenance control and the local mechanic employed the MEL placarding the lavatories on the ground; but they would be available in-flight. Mechanic pulled a 2.5 amp circuit breaker labeled 'vacuum waste' behind the captain and completed the logbook sign off. Thirty minutes into flight the flight attendants notified us the lavatories were worse than before and beginning to fill up. After closer inspection of the MEL; I realized the mechanic should have pulled a 20 amp circuit breaker labeled 'vacuum toilet blower motor' behind panel P91 (later determined to be in the east&east compartment) not 'vacuum waste.' after receiving permission from maintenance control the 'vacuum waste' circuit breaker was reset and the lavatories began to function. Flight was continued to our destination.

Original NASA ASRS Text

Title: A B737-800's lavatory vacuum motor worked poorly on the ground. A Contract Mechanic applied the MEL incorrectly and during flight the lavatories filled. The flight crew discovered an incorrect circuit breaker was pulled preventing pressurization vacuum from operating the lavatories.

Narrative: Shortly before departure; we were notified by the flight attendants that all three lavatories were inoperative. After further investigation; we realized that the lavatories would flush but without much suction. Contract Maintenance was notified and the troubleshooting began. Ultimately; Maintenance Control and the local Mechanic employed the MEL placarding the lavatories on the ground; but they would be available in-flight. Mechanic pulled a 2.5 AMP circuit breaker labeled 'vacuum waste' behind the Captain and completed the logbook sign off. Thirty minutes into flight the flight attendants notified us the lavatories were worse than before and beginning to fill up. After closer inspection of the MEL; I realized the mechanic should have pulled a 20 AMP circuit breaker labeled 'vacuum toilet blower motor' behind panel P91 (later determined to be in the E&E compartment) not 'vacuum waste.' After receiving permission from Maintenance Control the 'vacuum waste' circuit breaker was reset and the lavatories began to function. Flight was continued to our destination.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	848866
Time
Date	200908
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Light	Daylight
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Taxi Parked
Flight Plan	IFR
Component
Aircraft Component	Waste Water Disposal System
Person 1
Function	Captain Pilot Flying
Person 2
Function	First Officer Pilot Not Flying
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural MEL

A B737-800's lavatory vacuum motor worked poorly on the ground. A contract mechanic applied the MEL incorrectly and during flight the lavatories filled. The flight crew discovered an incorrect circuit breaker was pulled preventing pressurization vacuum from operating the lavatories.