Narrative:

I issued an engineering order to replace fuel nozzles on aircraft #2 engine. The engineering order was issued because of intermittent no start issues on this engine that was being tracked as a chronic problem. In the text of the engineering order the amm references and required parts were idented and annotated using air carrier part numbers. The appropriate ipc was utilized to identify the required parts to complete the task. Later I was advised that the removed fuel nozzles from this engine had arrived at the repair vendor and a disparity between the air carrier service order part number and the actual fuel nozzle part number existed. Research was conducted to track how this could happen. I reviewed the original engineering order after xchking the air carrier to manufacturer's part number an error was discovered on one of air carrier part numbers. Note: 2 part numbers are effective for the CFM56-7 engine. X 16 locations X 4 locations. Part number converts to air carrier part number B. Part number X converts to air carrier part number Z. What I believe happened is when I entered part number X into stores inventory system to convert to the air carrier part number; a typographical error was made and I entered Y which happens to be the part number for the CFM56-3 fuel nozzle in the same locations. This fuel nozzle converts to air carrier #X. No flag was evident because many of the parts required for fuel nozzle replacement are used on both engine models.

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Original NASA ASRS Text

Title: A B737-700/800 ACFT HAD INCORRECT FUEL NOZZLES INSTALLED DUE TO INCORRECT PART NUMBERS ON ENGINEERING DIRECTIVE.

Narrative: I ISSUED AN ENGINEERING ORDER TO REPLACE FUEL NOZZLES ON ACFT #2 ENG. THE ENGINEERING ORDER WAS ISSUED BECAUSE OF INTERMITTENT NO START ISSUES ON THIS ENG THAT WAS BEING TRACKED AS A CHRONIC PROB. IN THE TEXT OF THE ENGINEERING ORDER THE AMM REFS AND REQUIRED PARTS WERE IDENTED AND ANNOTATED USING ACR PART NUMBERS. THE APPROPRIATE IPC WAS UTILIZED TO IDENT THE REQUIRED PARTS TO COMPLETE THE TASK. LATER I WAS ADVISED THAT THE REMOVED FUEL NOZZLES FROM THIS ENG HAD ARRIVED AT THE REPAIR VENDOR AND A DISPARITY BTWN THE ACR SVC ORDER PART NUMBER AND THE ACTUAL FUEL NOZZLE PART NUMBER EXISTED. RESEARCH WAS CONDUCTED TO TRACK HOW THIS COULD HAPPEN. I REVIEWED THE ORIGINAL ENGINEERING ORDER AFTER XCHKING THE ACR TO MANUFACTURER'S PART NUMBER AN ERROR WAS DISCOVERED ON ONE OF ACR PART NUMBERS. NOTE: 2 PART NUMBERS ARE EFFECTIVE FOR THE CFM56-7 ENG. X 16 LOCATIONS X 4 LOCATIONS. PART NUMBER CONVERTS TO ACR PART NUMBER B. PART NUMBER X CONVERTS TO ACR PART NUMBER Z. WHAT I BELIEVE HAPPENED IS WHEN I ENTERED PART NUMBER X INTO STORES INVENTORY SYS TO CONVERT TO THE ACR PART NUMBER; A TYPOGRAPHICAL ERROR WAS MADE AND I ENTERED Y WHICH HAPPENS TO BE THE PART NUMBER FOR THE CFM56-3 FUEL NOZZLE IN THE SAME LOCATIONS. THIS FUEL NOZZLE CONVERTS TO ACR #X. NO FLAG WAS EVIDENT BECAUSE MANY OF THE PARTS REQUIRED FOR FUEL NOZZLE REPLACEMENT ARE USED ON BOTH ENG MODELS.

Data retrieved from NASA's ASRS site as of January 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.