Narrative:

Upon research under the air carrier inventory system it has been discovered that the serial numbers do not agree with the position of the unit installed in the aircraft. This may cause the wrong part (a or B of the engineering order) to be issued to the mechanic. This is not intended as a job card correction; but a correction in the air carrier system. Engineering order contains a part a (flap) and a part B (slat) for the xfer tubes of the power control units total of 8 per aircraft. Four of them are being issued to the mechanic as part a or B. The other four are not issued to inspect at all. If the mechanic chooses to inspect them. It has been known to find bad batch numbered tubes in the PCU (power control units) motors and replace them per the non-issued job card part (ex a or B). The known bad tubes were replaced. Do not north/a any part of this engineering order. A time saving revision was made to this engineering order with the help of engineering. And it will not waste any time to inspect the other PCU. Callback conversation with reporter revealed the following information: reporter stated the issue centers around an engineering order to replace the hydraulic transfer tubes for the slat or flaps if the tubes have a certain number stamped on the tube. The original tubes are cracking. Reporter notes he was instrumental in getting his carrier to change the procedure to use a borescope process to locate the stamped number on the outside of the suspect tube without having to remove all eight tubes involved in the slat/flap PCU transfer system. Adding to the problem however; is the stores inventory system was found to have inaccurate serial numbers for the specific locations of the slat/flap transfer tubes; basically the serial numbers were reversed for the slat/flap tube positions. Sometimes only the flap or slat transfer tubes were checked and if required replaced; but with incorrect new tubes due to incorrect inventory data.

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Original NASA ASRS Text

Title: ACFT STORES INVENTORY SYSTEM AT REPORTER'S AIR CARRIER HAS FOUND THE SERIAL NUMBERS DO NOT AGREE WITH THE POSITION OF THE UNITS INSTALLED IN THE ACFT.

Narrative: UPON RESEARCH UNDER THE ACR INVENTORY SYS IT HAS BEEN DISCOVERED THAT THE SERIAL NUMBERS DO NOT AGREE WITH THE POS OF THE UNIT INSTALLED IN THE ACFT. THIS MAY CAUSE THE WRONG PART (A OR B OF THE ENGINEERING ORDER) TO BE ISSUED TO THE MECH. THIS IS NOT INTENDED AS A JOB CARD CORRECTION; BUT A CORRECTION IN THE ACR SYS. ENGINEERING ORDER CONTAINS A PART A (FLAP) AND A PART B (SLAT) FOR THE XFER TUBES OF THE PWR CTL UNITS TOTAL OF 8 PER ACFT. FOUR OF THEM ARE BEING ISSUED TO THE MECH AS PART A OR B. THE OTHER FOUR ARE NOT ISSUED TO INSPECT AT ALL. IF THE MECH CHOOSES TO INSPECT THEM. IT HAS BEEN KNOWN TO FIND BAD BATCH NUMBERED TUBES IN THE PCU (PWR CTL UNITS) MOTORS AND REPLACE THEM PER THE NON-ISSUED JOB CARD PART (EX A OR B). THE KNOWN BAD TUBES WERE REPLACED. DO NOT N/A ANY PART OF THIS ENGINEERING ORDER. A TIME SAVING REVISION WAS MADE TO THIS ENGINEERING ORDER WITH THE HELP OF ENGINEERING. AND IT WILL NOT WASTE ANY TIME TO INSPECT THE OTHER PCU. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE ISSUE CENTERS AROUND AN ENGINEERING ORDER TO REPLACE THE HYD TRANSFER TUBES FOR THE SLAT OR FLAPS IF THE TUBES HAVE A CERTAIN NUMBER STAMPED ON THE TUBE. THE ORIGINAL TUBES ARE CRACKING. REPORTER NOTES HE WAS INSTRUMENTAL IN GETTING HIS CARRIER TO CHANGE THE PROCEDURE TO USE A BORESCOPE PROCESS TO LOCATE THE STAMPED NUMBER ON THE OUTSIDE OF THE SUSPECT TUBE WITHOUT HAVING TO REMOVE ALL EIGHT TUBES INVOLVED IN THE SLAT/FLAP PCU TRANSFER SYSTEM. ADDING TO THE PROBLEM HOWEVER; IS THE STORES INVENTORY SYSTEM WAS FOUND TO HAVE INACCURATE SERIAL NUMBERS FOR THE SPECIFIC LOCATIONS OF THE SLAT/FLAP TRANSFER TUBES; BASICALLY THE SERIAL NUMBERS WERE REVERSED FOR THE SLAT/FLAP TUBE POSITIONS. SOMETIMES ONLY THE FLAP OR SLAT TRANSFER TUBES WERE CHECKED AND IF REQUIRED REPLACED; BUT WITH INCORRECT NEW TUBES DUE TO INCORRECT INVENTORY DATA.

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.