Narrative:

Aircraft dispatched mem-mci with MEL xyz. WX good both mem and mci. Revised MEL procedure (mar/97) said aircraft may be operated with 1 pack inoperative provided no discrepancies on operative pack last 10 days. I checked with maintenance control and dispatch who checked (rptedly) with FAA who interpreted 10 days to be prior to MEL date. (Discrepancy noted, resulted in water separator bag being changed.) after consultation, I elected to take aircraft. Flight operated without incident. At mci, dispatch and maintenance decided to dispatch aircraft unpressurized. In conclusion, MEL xyz is unclr and should be revised or clarified. Supplemental information from acn 370476: this situation concerns a passenger DC9-30 with a right air conditioning pack on MEL. The MEL states 'no discrepancies that could affect pressurization have occurred on the operative pack over the past 10 days.' the left, or operative pack had a write-up cleared the day before this situation. The captain asked for concurrence from dispatch and maintenance to operate the flight. The dispute centered around the interpretation of the 10 day period. Supervisory personnel became involved. Finally it was agreed by all parties it was legal to go based on the word or opinion of the maintenance manager who was involved in writing this MEL. He stated the FAA intent was that the 10 day period was the 10 days prior to the date of adding the MEL. Thus, this flight was legal to operate. Consequently, on this aircraft's next leg, another dispatcher again asked for clarification of the MEL. He asked for written proof that the FAA interpretation given on the previous leg was correct. The same maintenance personnel said they couldn't produce proof so that flight was not operated. The problem is the pilot, dispatcher, and maintenance controller of the first flight risked their professional integrity on what they thought was a reliable source of information. The back-pedalling by maintenance was alarming and brought their motives into question. It was mentioned from the beginning of the problem to just call the FAA for an interpretation. However, no one involved wanted to go forward with that for fear of reprisal. It would be most helpful and contribute to safety if operators and the FAA had some way to resolve this type of situation on the spot with impunity for the questioners.

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Original NASA ASRS Text

Title: FLC OF A DC9 ACCEPT THE ACFT WITH 1 AIR CONDITIONING PACK INOP. THAT WAS ON THE CONDITION THAT THERE HADN'T BEEN ANY MAINT DISCREPANCIES ON THE OPERATIVE PACK WITHIN THE PRIOR 10 DAYS. ACFT ARRIVES AT DEST ARPT AND RPTR FINDS THAT ACFT IS NOW TO FLY (SANS PAX) UNPRESSURIZED.

Narrative: ACFT DISPATCHED MEM-MCI WITH MEL XYZ. WX GOOD BOTH MEM AND MCI. REVISED MEL PROC (MAR/97) SAID ACFT MAY BE OPERATED WITH 1 PACK INOP PROVIDED NO DISCREPANCIES ON OPERATIVE PACK LAST 10 DAYS. I CHKED WITH MAINT CTL AND DISPATCH WHO CHKED (RPTEDLY) WITH FAA WHO INTERPRETED 10 DAYS TO BE PRIOR TO MEL DATE. (DISCREPANCY NOTED, RESULTED IN WATER SEPARATOR BAG BEING CHANGED.) AFTER CONSULTATION, I ELECTED TO TAKE ACFT. FLT OPERATED WITHOUT INCIDENT. AT MCI, DISPATCH AND MAINT DECIDED TO DISPATCH ACFT UNPRESSURIZED. IN CONCLUSION, MEL XYZ IS UNCLR AND SHOULD BE REVISED OR CLARIFIED. SUPPLEMENTAL INFO FROM ACN 370476: THIS SIT CONCERNS A PAX DC9-30 WITH A R AIR CONDITIONING PACK ON MEL. THE MEL STATES 'NO DISCREPANCIES THAT COULD AFFECT PRESSURIZATION HAVE OCCURRED ON THE OPERATIVE PACK OVER THE PAST 10 DAYS.' THE L, OR OPERATIVE PACK HAD A WRITE-UP CLRED THE DAY BEFORE THIS SIT. THE CAPT ASKED FOR CONCURRENCE FROM DISPATCH AND MAINT TO OPERATE THE FLT. THE DISPUTE CENTERED AROUND THE INTERPRETATION OF THE 10 DAY PERIOD. SUPERVISORY PERSONNEL BECAME INVOLVED. FINALLY IT WAS AGREED BY ALL PARTIES IT WAS LEGAL TO GO BASED ON THE WORD OR OPINION OF THE MAINT MGR WHO WAS INVOLVED IN WRITING THIS MEL. HE STATED THE FAA INTENT WAS THAT THE 10 DAY PERIOD WAS THE 10 DAYS PRIOR TO THE DATE OF ADDING THE MEL. THUS, THIS FLT WAS LEGAL TO OPERATE. CONSEQUENTLY, ON THIS ACFT'S NEXT LEG, ANOTHER DISPATCHER AGAIN ASKED FOR CLARIFICATION OF THE MEL. HE ASKED FOR WRITTEN PROOF THAT THE FAA INTERPRETATION GIVEN ON THE PREVIOUS LEG WAS CORRECT. THE SAME MAINT PERSONNEL SAID THEY COULDN'T PRODUCE PROOF SO THAT FLT WAS NOT OPERATED. THE PROB IS THE PLT, DISPATCHER, AND MAINT CTLR OF THE FIRST FLT RISKED THEIR PROFESSIONAL INTEGRITY ON WHAT THEY THOUGHT WAS A RELIABLE SOURCE OF INFORMATION. THE BACK-PEDALLING BY MAINT WAS ALARMING AND BROUGHT THEIR MOTIVES INTO QUESTION. IT WAS MENTIONED FROM THE BEGINNING OF THE PROB TO JUST CALL THE FAA FOR AN INTERPRETATION. HOWEVER, NO ONE INVOLVED WANTED TO GO FORWARD WITH THAT FOR FEAR OF REPRISAL. IT WOULD BE MOST HELPFUL AND CONTRIBUTE TO SAFETY IF OPERATORS AND THE FAA HAD SOME WAY TO RESOLVE THIS TYPE OF SIT ON THE SPOT WITH IMPUNITY FOR THE QUESTIONERS.

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.