Narrative:

Flight was dispatched with 2 MEL's on it. MEL X and Y; which may be in conflict. On apr/xa/08 I dispatched it on flight and the captain questioned it and refused the aircraft. We swapped out aircraft to keep the operation moving; but this brought out the red flags. I inquired with our training instructors on the meaning and intent of the MEL's when applied together. They brought it to the attention of the maintenance department and the interpretation of the 2 MEL's applied together is still in question. At this time I still do not know if it's permissible or not. When we brought the issue before the A320 MEL supervisor his interpretation was as follows: yes; I would agree with you that these 2 MEL's should not be simultaneously applied. It looks like the automatic/brake function MEL was installed first and then the main wheel braking. If this in fact is true I can understand how the 2 mels got applied to the aircraft. Had the main wheel braking been installed first; I doubt after reviewing the MEL anyone would have installed the automatic/brake MEL as it contains specific reference to the normal braking not being affected -- surely a deactivated brake affects the normal braking. Currently the only fail-safe to the process of preventing conflicting MEL application is the user reviewing the current MEL status of the aircraft and what effects adding another MEL to it will have. The MEL isn't written to account for all the possible MEL combinations and their effects on each other. Despite the above interpretation; maintenance control contends that this is not an issue; but it has raised enough concern amongst both pilots and dispatchers that it warrants attention and further clarification. At a minimum the language in the MEL should be reviewed to provide more specific guidance when potential conflicts such as this occur. The initial concern was brought to my attention by the captain who questioned the operation with both MEL's applied at the same time. Lack of clear guidance regarding language and interpretation of existing MEL procedures when one or more items within the same air traffic area system are applied simultaneously. Clarification of language within the MEL manual when applying items within the same air traffic area chapter simultaneously. Callback conversation with reporter revealed the following information: reporter stated he still does not know; even at this time; if maintenance control was incorrect in simultaneously applying the 'automatic/brake function' and the 'main wheel braking' MEL to the aircraft maintenance release. Reporter stated when the captain refused the aircraft; maintenance informed him the aircraft would be taken out of service and at least one of the MEL items would be corrected. Instead the aircraft flew for two more flights the following day; without either MEL item being repaired. Aircraft was finally taken out of service.

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Original NASA ASRS Text

Title: A DISPATCHER QUESTIONS MAINT CONTROL FOR RELEASING AN AIRBUS A320 ACFT USING TWO MEL'S; SIMULTANEOUSLY; FOR 'AUTO-BRAKE FUNCTION' AND THE 'MAIN WHEEL BRAKING' DISCREPANCIES. CAPTAIN REFUSED ACFT.

Narrative: FLT WAS DISPATCHED WITH 2 MEL'S ON IT. MEL X AND Y; WHICH MAY BE IN CONFLICT. ON APR/XA/08 I DISPATCHED IT ON FLT AND THE CAPT QUESTIONED IT AND REFUSED THE ACFT. WE SWAPPED OUT ACFT TO KEEP THE OP MOVING; BUT THIS BROUGHT OUT THE RED FLAGS. I INQUIRED WITH OUR TRAINING INSTRUCTORS ON THE MEANING AND INTENT OF THE MEL'S WHEN APPLIED TOGETHER. THEY BROUGHT IT TO THE ATTN OF THE MAINT DEPT AND THE INTERP OF THE 2 MEL'S APPLIED TOGETHER IS STILL IN QUESTION. AT THIS TIME I STILL DO NOT KNOW IF IT'S PERMISSIBLE OR NOT. WHEN WE BROUGHT THE ISSUE BEFORE THE A320 MEL SUPVR HIS INTERP WAS AS FOLLOWS: YES; I WOULD AGREE WITH YOU THAT THESE 2 MEL'S SHOULD NOT BE SIMULTANEOUSLY APPLIED. IT LOOKS LIKE THE AUTO/BRAKE FUNCTION MEL WAS INSTALLED FIRST AND THEN THE MAIN WHEEL BRAKING. IF THIS IN FACT IS TRUE I CAN UNDERSTAND HOW THE 2 MELS GOT APPLIED TO THE ACFT. HAD THE MAIN WHEEL BRAKING BEEN INSTALLED FIRST; I DOUBT AFTER REVIEWING THE MEL ANYONE WOULD HAVE INSTALLED THE AUTO/BRAKE MEL AS IT CONTAINS SPECIFIC REF TO THE NORMAL BRAKING NOT BEING AFFECTED -- SURELY A DEACTIVATED BRAKE AFFECTS THE NORMAL BRAKING. CURRENTLY THE ONLY FAIL-SAFE TO THE PROCESS OF PREVENTING CONFLICTING MEL APPLICATION IS THE USER REVIEWING THE CURRENT MEL STATUS OF THE ACFT AND WHAT EFFECTS ADDING ANOTHER MEL TO IT WILL HAVE. THE MEL ISN'T WRITTEN TO ACCOUNT FOR ALL THE POSSIBLE MEL COMBINATIONS AND THEIR EFFECTS ON EACH OTHER. DESPITE THE ABOVE INTERP; MAINT CTL CONTENDS THAT THIS IS NOT AN ISSUE; BUT IT HAS RAISED ENOUGH CONCERN AMONGST BOTH PLTS AND DISPATCHERS THAT IT WARRANTS ATTN AND FURTHER CLARIFICATION. AT A MINIMUM THE LANGUAGE IN THE MEL SHOULD BE REVIEWED TO PROVIDE MORE SPECIFIC GUIDANCE WHEN POTENTIAL CONFLICTS SUCH AS THIS OCCUR. THE INITIAL CONCERN WAS BROUGHT TO MY ATTN BY THE CAPT WHO QUESTIONED THE OP WITH BOTH MEL'S APPLIED AT THE SAME TIME. LACK OF CLR GUIDANCE REGARDING LANGUAGE AND INTERP OF EXISTING MEL PROCS WHEN ONE OR MORE ITEMS WITHIN THE SAME ATA SYS ARE APPLIED SIMULTANEOUSLY. CLARIFICATION OF LANGUAGE WITHIN THE MEL MANUAL WHEN APPLYING ITEMS WITHIN THE SAME ATA CHAPTER SIMULTANEOUSLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED HE STILL DOES NOT KNOW; EVEN AT THIS TIME; IF MAINT CONTROL WAS INCORRECT IN SIMULTANEOUSLY APPLYING THE 'AUTO/BRAKE FUNCTION' AND THE 'MAIN WHEEL BRAKING' MEL TO THE ACFT MAINT RELEASE. REPORTER STATED WHEN THE CAPTAIN REFUSED THE ACFT; MAINT INFORMED HIM THE ACFT WOULD BE TAKEN OUT OF SERVICE AND AT LEAST ONE OF THE MEL ITEMS WOULD BE CORRECTED. INSTEAD THE ACFT FLEW FOR TWO MORE FLIGHTS THE FOLLOWING DAY; WITHOUT EITHER MEL ITEM BEING REPAIRED. ACFT WAS FINALLY TAKEN OUT OF SERVICE.

Data retrieved from NASA's ASRS site as of May 2009 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.