Narrative:

This event concerns my operation of two flight legs from atl-cae-atl with two maintenance discrepancies filed in the aircraft log book as maintenance carryovers (mco's), maintenance items deferred for latter corrective action. When I picked up my flight plan and flight dispatch release I had two maintenance carryovers listed under their MEL (minimum equipment list) numbers xa-0007B (red low oil pressure lights) and xb- 0016 (master caution lights). The listing of these in the dispatch release constituted a legal dispatch under the auspices of maintenance control and the flight dispatcher. I proceeded to the aircraft and checked the 2 mco's for the detailed description in the aircraft logbook. The item xb-0016 (master caution lights) said that the center tank fuel low pressure lights did not cause the illumination of the master caution lights. This was a minor component part of the master caution system and was legal under the MEL. Our preflight indicated that the master caution system itself was operational. The second mco xa-0007B indicated that the left engine red low oil pressure light was inoperative. The MEL said this condition was acceptable as long as the yellow low pressure light was operating, the low oil pressure annunciating system and the master caution light system were operational. Since the master caution system problem was isolated to the low pressure fuel annunciators in the center fuel tank I considered the low oil pressure light maintenance discrepancy in compliance with the MEL. These writeups were discussed with the first officer. Our flight dispatch included both mco's. The log book contained the discrepancies plus the correct paperwork from maintenance to defer the discrepancies to mco. We therefore considered ourselves in compliance with the MEL for dispatch. An uneventful flight was conducted to cae. In cae the dispatcher contacted us along with maintenance to discuss the legality of these two writeups. Again it was concluded that we were in compliance with the MEL. This is a continued gray area we must deal with in interpreting the minimum requirement list. Does a partial system malfunction render an entire system inoperative or is it legal to operate with a partially operative system? FAA guidance in this error is vague and not consistent.

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Original NASA ASRS Text

Title: AN MD88 WAS DISPATCHED WITH TWO DEFERRED ITEMS THAT THE CREW REQUESTED MINIMUM EQUIP LIST INTERPRETATION.

Narrative: THIS EVENT CONCERNS MY OPERATION OF TWO FLT LEGS FROM ATL-CAE-ATL WITH TWO MAINT DISCREPANCIES FILED IN THE ACFT LOG BOOK AS MAINT CARRYOVERS (MCO'S), MAINT ITEMS DEFERRED FOR LATTER CORRECTIVE ACTION. WHEN I PICKED UP MY FLT PLAN AND FLT DISPATCH RELEASE I HAD TWO MAINT CARRYOVERS LISTED UNDER THEIR MEL (MINIMUM EQUIP LIST) NUMBERS XA-0007B (RED LOW OIL PRESSURE LIGHTS) AND XB- 0016 (MASTER CAUTION LIGHTS). THE LISTING OF THESE IN THE DISPATCH RELEASE CONSTITUTED A LEGAL DISPATCH UNDER THE AUSPICES OF MAINT CTL AND THE FLT DISPATCHER. I PROCEEDED TO THE ACFT AND CHKED THE 2 MCO'S FOR THE DETAILED DESCRIPTION IN THE ACFT LOGBOOK. THE ITEM XB-0016 (MASTER CAUTION LIGHTS) SAID THAT THE CTR TANK FUEL LOW PRESSURE LIGHTS DID NOT CAUSE THE ILLUMINATION OF THE MASTER CAUTION LIGHTS. THIS WAS A MINOR COMPONENT PART OF THE MASTER CAUTION SYSTEM AND WAS LEGAL UNDER THE MEL. OUR PREFLT INDICATED THAT THE MASTER CAUTION SYSTEM ITSELF WAS OPERATIONAL. THE SECOND MCO XA-0007B INDICATED THAT THE L ENG RED LOW OIL PRESSURE LIGHT WAS INOP. THE MEL SAID THIS CONDITION WAS ACCEPTABLE AS LONG AS THE YELLOW LOW PRESSURE LIGHT WAS OPERATING, THE LOW OIL PRESSURE ANNUNCIATING SYSTEM AND THE MASTER CAUTION LIGHT SYSTEM WERE OPERATIONAL. SINCE THE MASTER CAUTION SYS PROB WAS ISOLATED TO THE LOW PRESSURE FUEL ANNUNCIATORS IN THE CTR FUEL TANK I CONSIDERED THE LOW OIL PRESSURE LIGHT MAINT DISCREPANCY IN COMPLIANCE WITH THE MEL. THESE WRITEUPS WERE DISCUSSED WITH THE FO. OUR FLT DISPATCH INCLUDED BOTH MCO'S. THE LOG BOOK CONTAINED THE DISCREPANCIES PLUS THE CORRECT PAPERWORK FROM MAINT TO DEFER THE DISCREPANCIES TO MCO. WE THEREFORE CONSIDERED OURSELVES IN COMPLIANCE WITH THE MEL FOR DISPATCH. AN UNEVENTFUL FLT WAS CONDUCTED TO CAE. IN CAE THE DISPATCHER CONTACTED US ALONG WITH MAINT TO DISCUSS THE LEGALITY OF THESE TWO WRITEUPS. AGAIN IT WAS CONCLUDED THAT WE WERE IN COMPLIANCE WITH THE MEL. THIS IS A CONTINUED GRAY AREA WE MUST DEAL WITH IN INTERPRETING THE MINIMUM REQUIREMENT LIST. DOES A PARTIAL SYSTEM MALFUNCTION RENDER AN ENTIRE SYSTEM INOP OR IS IT LEGAL TO OPERATE WITH A PARTIALLY OPERATIVE SYSTEM? FAA GUIDANCE IN THIS ERROR IS VAGUE AND NOT CONSISTENT.

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.