Narrative:

I believe that on nov/mon/04 I was working on aircraft X. I was working with 3 other men. After mr X and I finished the service check and some other write-ups, he started working on a deferred item. He first went up to the door panel display unit to verify the write-up and found that all of the lavatory indications were inoperative. Mr X then proceeded to the east&east compartment and found that the circuit breaker for the zone 3 xfer bus was popped. Mr X tried to reset the circuit breaker and was unable to do so. This is the point that I showed up. I followed the same process that mr X had just done. And then we both went to the computer in the gate house to look at the wire diagram and started looking in chapter 23 for the circuit breaker and what was in that circuit which led up to wd 23-35-55 but we could not find the zone management units. Mr Y came to help us with this problem and we started looking for the zone management units, buffer box, and overhead electronics unit to see if there was any circuit breaker popped. We did not find any circuit breakers to reset so we started to look for other problems. Mr Z showed up about this point and we started to break the circuit open. With mr Z's knowledge we were able to find some other circuits that may also have caused this problem and found the cannon plugs and pulled them but only D1360 allowed the circuit breaker to reset. We pulled the connectors from each one of the overhead electronics units and could not find the problem. We ran out of time on the layover and we thought that it should be time to close up and defer if we could. I called the system maintenance controller. We talked about the problem that we were having and we agreed that from the print that we were working with the only system that would be affected would be the entertainment and seat function for the right side of the aircraft from door 3R to door 4R. We agreed that we could pull the connector D1360 and tie it back until the problem could be found. Nobody seems to know that the oxygen generation system would be affected. I do not know if we had checked connector D5181 but the work was signed off on ptt-XXX. It is my understanding that mr a was assigned to work the deferral and found the problem on nov/fri/04 and corrected the problem.

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Original NASA ASRS Text

Title: A B777-200 HAD ALL LAVATORY INDICATIONS INOP. ISOLATED PROB TO R SIDE BTWN DOOR 3RT AND DOOR 4RT. TIED BACK CONNECTOR AND DEFERRED ITEM. INADVERTENTLY RENDERED PAX EMER OXYGEN INOP.

Narrative: I BELIEVE THAT ON NOV/MON/04 I WAS WORKING ON ACFT X. I WAS WORKING WITH 3 OTHER MEN. AFTER MR X AND I FINISHED THE SVC CHK AND SOME OTHER WRITE-UPS, HE STARTED WORKING ON A DEFERRED ITEM. HE FIRST WENT UP TO THE DOOR PANEL DISPLAY UNIT TO VERIFY THE WRITE-UP AND FOUND THAT ALL OF THE LAVATORY INDICATIONS WERE INOP. MR X THEN PROCEEDED TO THE E&E COMPARTMENT AND FOUND THAT THE CIRCUIT BREAKER FOR THE ZONE 3 XFER BUS WAS POPPED. MR X TRIED TO RESET THE CIRCUIT BREAKER AND WAS UNABLE TO DO SO. THIS IS THE POINT THAT I SHOWED UP. I FOLLOWED THE SAME PROCESS THAT MR X HAD JUST DONE. AND THEN WE BOTH WENT TO THE COMPUTER IN THE GATE HOUSE TO LOOK AT THE WIRE DIAGRAM AND STARTED LOOKING IN CHAPTER 23 FOR THE CIRCUIT BREAKER AND WHAT WAS IN THAT CIRCUIT WHICH LED UP TO WD 23-35-55 BUT WE COULD NOT FIND THE ZONE MGMNT UNITS. MR Y CAME TO HELP US WITH THIS PROB AND WE STARTED LOOKING FOR THE ZONE MGMNT UNITS, BUFFER BOX, AND OVERHEAD ELECTRONICS UNIT TO SEE IF THERE WAS ANY CIRCUIT BREAKER POPPED. WE DID NOT FIND ANY CIRCUIT BREAKERS TO RESET SO WE STARTED TO LOOK FOR OTHER PROBS. MR Z SHOWED UP ABOUT THIS POINT AND WE STARTED TO BREAK THE CIRCUIT OPEN. WITH MR Z'S KNOWLEDGE WE WERE ABLE TO FIND SOME OTHER CIRCUITS THAT MAY ALSO HAVE CAUSED THIS PROB AND FOUND THE CANNON PLUGS AND PULLED THEM BUT ONLY D1360 ALLOWED THE CIRCUIT BREAKER TO RESET. WE PULLED THE CONNECTORS FROM EACH ONE OF THE OVERHEAD ELECTRONICS UNITS AND COULD NOT FIND THE PROB. WE RAN OUT OF TIME ON THE LAYOVER AND WE THOUGHT THAT IT SHOULD BE TIME TO CLOSE UP AND DEFER IF WE COULD. I CALLED THE SYS MAINT CTLR. WE TALKED ABOUT THE PROB THAT WE WERE HAVING AND WE AGREED THAT FROM THE PRINT THAT WE WERE WORKING WITH THE ONLY SYS THAT WOULD BE AFFECTED WOULD BE THE ENTERTAINMENT AND SEAT FUNCTION FOR THE R SIDE OF THE ACFT FROM DOOR 3R TO DOOR 4R. WE AGREED THAT WE COULD PULL THE CONNECTOR D1360 AND TIE IT BACK UNTIL THE PROB COULD BE FOUND. NOBODY SEEMS TO KNOW THAT THE OXYGEN GENERATION SYS WOULD BE AFFECTED. I DO NOT KNOW IF WE HAD CHKED CONNECTOR D5181 BUT THE WORK WAS SIGNED OFF ON PTT-XXX. IT IS MY UNDERSTANDING THAT MR A WAS ASSIGNED TO WORK THE DEFERRAL AND FOUND THE PROB ON NOV/FRI/04 AND CORRECTED THE PROB.

Data retrieved from NASA's ASRS site as of July 2007 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.