Narrative:

Aircraft was dispatched previously with the following mels: right engine eec (right engine electronic control); thrust management. Upon arrival at our airport another discrepancy was added to the logbook. The captain reported that LNAV was not properly sequencing waypoints. On the leg before last; an erroneous turn was initiated by the autoflight system. The cause of this error was unverified until the same anomaly occurred on the subsequent flight before our scheduled leg; where the autoflight system failed to properly execute the RNAV departure. The discrepancy was noted in the logbook. Line maintenance attempted to reload the navigation database as it was suspected to be corrupted. The reload could not be accomplished because the necessary equipment required to download the data into the aircraft was not available here. The line mechanic was told to add MEL 34-61-01 to the logbook. He informed us that he was not comfortable releasing an aircraft with multiple additive mels but was instructed to do so. The following mels/placards were placed on the logbook: 73-21-01 right engine eec; 22-30-01 thrust management; 34-61-01 left and right FMC inoperative; pla CAT ii prohibited; pla RNAV department/arrival prohibited; pla ETOPS prohibited. The cockpit crew determined that such a degraded level of automation was a serious threat to flight safety. The line mechanic concurred. Dispatch was informed and the flight was canceled. Pressure to maintain schedule and lack of necessary repair equipment at this major station was an issue. Successful upload of a new navigation database would have allowed dispatch. Safety was compromised when MEL 34-61-01 was added to the logbook. This action placed the burden of risk analysis on the pilots; rather than having operations management assume that responsibility. When it was known that a possible corrupt database could not be reloaded; the flight should have been canceled at that point. To MEL both FMC's in addition to the thrust management being inoperative allowed the possibility that a pilot would fly this aircraft in a seriously degraded condition. The line mechanic was not fully supportive of the decision to add another MEL on an already degraded aircraft but was directed to do so anyway. As far as a suggestion as to how to prevent a recurrence of this event; I would be at a loss as to where to start. This airline's commitment to a safety culture as was certainly not evident by this event. It appears that safety was foremost on the minds of the line mechanic and the flight crew; whereas schedule was the driving force of management.

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Original NASA ASRS Text

Title: A B757 Captain refused an aircraft because a corrupt FMC database could not be replaced and the aircraft already had several MEL's affecting aircraft power plant management.

Narrative: Aircraft was dispatched previously with the following MELs: R ENG EEC (right engine electronic control); THRUST MANAGEMENT. Upon arrival at our airport another discrepancy was added to the logbook. The Captain reported that LNAV was not properly sequencing waypoints. On the leg before last; an erroneous turn was initiated by the autoflight system. The cause of this error was unverified until the same anomaly occurred on the subsequent flight before our scheduled leg; where the autoflight system failed to properly execute the RNAV departure. The discrepancy was noted in the logbook. Line Maintenance attempted to reload the NAV DATABASE as it was suspected to be corrupted. The reload could not be accomplished because the necessary equipment required to download the data into the aircraft was not available here. The line mechanic was told to add MEL 34-61-01 to the logbook. He informed us that he was not comfortable releasing an aircraft with multiple additive MELS but was instructed to do so. The following MELs/Placards were placed on the logbook: 73-21-01 R ENG EEC; 22-30-01 THRUST MANAGEMENT; 34-61-01 L and R FMC INOP; PLA CAT II PROHIBITED; PLA RNAV DEPT/ARR PROHIBITED; PLA ETOPS PROHIBITED. The cockpit crew determined that such a degraded level of automation was a serious threat to flight safety. The Line Mechanic concurred. Dispatch was informed and the flight was canceled. Pressure to maintain schedule and lack of necessary repair equipment at this major station was an issue. Successful upload of a new NAV database would have allowed dispatch. Safety was compromised when MEL 34-61-01 was added to the logbook. This action placed the burden of risk analysis on the pilots; rather than having Operations Management assume that responsibility. When it was known that a possible corrupt database could not be reloaded; the flight should have been canceled at that point. To MEL both FMC's in addition to the THRUST MANAGEMENT being inoperative allowed the possibility that a pilot would fly this aircraft in a seriously degraded condition. The Line Mechanic was not fully supportive of the decision to add another MEL on an already degraded aircraft but was directed to do so anyway. As far as a suggestion as to how to prevent a recurrence of this event; I would be at a loss as to where to start. This Airline's commitment to a safety culture as was certainly not evident by this event. It appears that safety was foremost on the minds of the Line Mechanic and the flight crew; whereas schedule was the driving force of Management.

Data retrieved from NASA's ASRS site as of April 2012 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.