Narrative:

When I came on duty about XA15 on may/thu/02, aircraft had an MEL 35-3. The MEL was on my current run. However, I was unaware of the requirement to check the passenger oxygen pressure prior to each departure. Prior to, I believe, flight to XXX, dispatch and the captain called me and questioned if the MEL required it to be inspected each flight. This is the first time I became aware of an inspection requirement directed by the MEL. I read the MEL and misinterped it to be at time of deferral only. It was documented in the logbook that the inspection was complied with at time of deferral. I told the captain and dispatcher this, and they said ok, and the flight continued on to destination where the flight terminated. It was a busy evening and the other controllers were all on the phone, otherwise I would have asked for their interpretation. Later in the evening, line called and said they did not have the part to repair the MEL. At this time, I reviewed the MEL again to consider carrying the MEL another day. At this time, I started to doubt my previous decision and I asked the other controllers for their interpretation and realized my error. The aircraft flew 4 legs during my shift without being inspected. We borrowed the required part from retired aircraft and repaired the MEL on aircraft. I also asked ZZZ line if the passenger oxygen bottle was still full upon arrival, and they said it was.

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Original NASA ASRS Text

Title: A B737-200 WAS DISPATCHED IN NON COMPLIANCE WITH THE PAX OXYGEN PRESSURE INDICATOR DEFERRED AS INOP BUT BOTTLE PRESSURE NOT VISUALLY CHKED PER MEL REQUIREMENTS.

Narrative: WHEN I CAME ON DUTY ABOUT XA15 ON MAY/THU/02, ACFT HAD AN MEL 35-3. THE MEL WAS ON MY CURRENT RUN. HOWEVER, I WAS UNAWARE OF THE REQUIREMENT TO CHK THE PAX OXYGEN PRESSURE PRIOR TO EACH DEP. PRIOR TO, I BELIEVE, FLT TO XXX, DISPATCH AND THE CAPT CALLED ME AND QUESTIONED IF THE MEL REQUIRED IT TO BE INSPECTED EACH FLT. THIS IS THE FIRST TIME I BECAME AWARE OF AN INSPECTION REQUIREMENT DIRECTED BY THE MEL. I READ THE MEL AND MISINTERPED IT TO BE AT TIME OF DEFERRAL ONLY. IT WAS DOCUMENTED IN THE LOGBOOK THAT THE INSPECTION WAS COMPLIED WITH AT TIME OF DEFERRAL. I TOLD THE CAPT AND DISPATCHER THIS, AND THEY SAID OK, AND THE FLT CONTINUED ON TO DEST WHERE THE FLT TERMINATED. IT WAS A BUSY EVENING AND THE OTHER CTLRS WERE ALL ON THE PHONE, OTHERWISE I WOULD HAVE ASKED FOR THEIR INTERP. LATER IN THE EVENING, LINE CALLED AND SAID THEY DID NOT HAVE THE PART TO REPAIR THE MEL. AT THIS TIME, I REVIEWED THE MEL AGAIN TO CONSIDER CARRYING THE MEL ANOTHER DAY. AT THIS TIME, I STARTED TO DOUBT MY PREVIOUS DECISION AND I ASKED THE OTHER CTLRS FOR THEIR INTERP AND REALIZED MY ERROR. THE ACFT FLEW 4 LEGS DURING MY SHIFT WITHOUT BEING INSPECTED. WE BORROWED THE REQUIRED PART FROM RETIRED ACFT AND REPAIRED THE MEL ON ACFT. I ALSO ASKED ZZZ LINE IF THE PAX OXYGEN BOTTLE WAS STILL FULL UPON ARR, AND THEY SAID IT WAS.

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.