Narrative:

Prior to departure from ZZZ on nov/sun/03, we were advised by maintenance that an air system write-up in the aircraft maintenance log (which would have required crew to operate the air system in the manual mode) was entered in error. They advised us that the MEL did not address the true problem on board the aircraft, and that a complete description of the aircraft problem would be discussed with the crew in ZZZ by the mechanic who had initiated the MEL in question. Until then, we were advised by maintenance to operate the aircraft with the air system in the automatic mode (against the procedures called for in the MEL), like 'all the other crews had operated.' we departed ZZZZ and proceeded to ZZZ and during descent to landing, we encountered icing conditions. After selecting the wing anti-ice system on, the left wing anti-ice disagree light came on. We selected the system off, and tried to avoid any icing conditions, and made an uneventful landing on runway 6R at ZZZ. After engine shutdown, a write-up was made in the aircraft maintenance log describing the event. The mechanic in describing the corrective action taken, stated the air system was operated in automatic mode against the procedures called for in the MEL, and signed off the write-up. Callback conversation with reporter revealed the following information: the reporter stated the deferred item was actually a left wing anti-ice disagree problem with a long maintenance history. The reporter said the instructions given to the crew by the ZZZ technician were to operate the air system in the automatic-mode which was not the procedure called for in the MEL. The reporter stated the inbound trip to ZZZ1 did encounter icing and when the wing anti-ice was switched on the left wing 'disagree' light came on. The reporter said on landing the item was written up in the maintenance log and the ZZZ1 technician cleared the item. The reporter stated the corrective action was the air system was operated in automatic in conflict with the MEL.

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Original NASA ASRS Text

Title: AN MD11 WAS DISPATCHED IN NON COMPLIANCE WITH AN AIR SYS MALFUNCTION NOT ADDRESSED IN THE MEL. INCORRECT OP PROCS GIVEN CREW.

Narrative: PRIOR TO DEP FROM ZZZ ON NOV/SUN/03, WE WERE ADVISED BY MAINT THAT AN AIR SYS WRITE-UP IN THE ACFT MAINT LOG (WHICH WOULD HAVE REQUIRED CREW TO OPERATE THE AIR SYS IN THE MANUAL MODE) WAS ENTERED IN ERROR. THEY ADVISED US THAT THE MEL DID NOT ADDRESS THE TRUE PROB ON BOARD THE ACFT, AND THAT A COMPLETE DESCRIPTION OF THE ACFT PROB WOULD BE DISCUSSED WITH THE CREW IN ZZZ BY THE MECH WHO HAD INITIATED THE MEL IN QUESTION. UNTIL THEN, WE WERE ADVISED BY MAINT TO OPERATE THE ACFT WITH THE AIR SYS IN THE AUTOMATIC MODE (AGAINST THE PROCS CALLED FOR IN THE MEL), LIKE 'ALL THE OTHER CREWS HAD OPERATED.' WE DEPARTED ZZZZ AND PROCEEDED TO ZZZ AND DURING DSCNT TO LNDG, WE ENCOUNTERED ICING CONDITIONS. AFTER SELECTING THE WING ANTI-ICE SYS ON, THE L WING ANTI-ICE DISAGREE LIGHT CAME ON. WE SELECTED THE SYS OFF, AND TRIED TO AVOID ANY ICING CONDITIONS, AND MADE AN UNEVENTFUL LNDG ON RWY 6R AT ZZZ. AFTER ENG SHUTDOWN, A WRITE-UP WAS MADE IN THE ACFT MAINT LOG DESCRIBING THE EVENT. THE MECH IN DESCRIBING THE CORRECTIVE ACTION TAKEN, STATED THE AIR SYS WAS OPERATED IN AUTOMATIC MODE AGAINST THE PROCS CALLED FOR IN THE MEL, AND SIGNED OFF THE WRITE-UP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE DEFERRED ITEM WAS ACTUALLY A L WING ANTI-ICE DISAGREE PROB WITH A LONG MAINT HISTORY. THE RPTR SAID THE INSTRUCTIONS GIVEN TO THE CREW BY THE ZZZ TECHNICIAN WERE TO OPERATE THE AIR SYS IN THE AUTO-MODE WHICH WAS NOT THE PROC CALLED FOR IN THE MEL. THE RPTR STATED THE INBOUND TRIP TO ZZZ1 DID ENCOUNTER ICING AND WHEN THE WING ANTI-ICE WAS SWITCHED ON THE L WING 'DISAGREE' LIGHT CAME ON. THE RPTR SAID ON LNDG THE ITEM WAS WRITTEN UP IN THE MAINT LOG AND THE ZZZ1 TECHNICIAN CLRED THE ITEM. THE RPTR STATED THE CORRECTIVE ACTION WAS THE AIR SYS WAS OPERATED IN AUTO IN CONFLICT WITH THE MEL.

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.