Narrative:

Aircraft X required the static inverter replaced. Working from the 757 wdm; I obtained the part number from the equipment list verifying effectivity and equipment identify arriving at a boeing specification part #s282t004-8. Part #s282t004-8 crossed in aircraft history to a stores part number; of which ZZZ1 stock showed 1 on hand. Upon receipt of the replacement inverter assembly; a difference in part numbers was observed between the received and unit being removed. It was my intention to have mr X right&right the inverter. Knowing of the part number differences; I suggested he first visit the ipc and confign documents acceptability to verify effectivity and possible ETOPS restrs. He returned with pages from the ipc indicating both remove and install units were shown effective to all aircraft. The ipc nomenclature column revealed no ETOPS restrs and both manufacturer part numbers cross-idented each other through 'service bulletin opt data.' a supplemental page was linked to this ipc figure which listed various manufacturer part numbers simply identing them as pre and post service bulletin 24-0110. Our install unit was determined to be pre service bulletin 24-0110. The confign document and acceptability list was consulted and revealed no restrs for any static inverters for our install part number. I too consulted the ipc; and confign document. A review of the ipc service bulletin and modification list revealed no service bulletin 24-0110. I came to the same conclusions as mr X regarding the effectivity of our install part number. The unit was effective to all aircraft with no ETOPS restrs; and service bulletin 24-0110 die not apply. At or about XA00 mr X installed the inverter. Amm 24-33-03. I completed the aircraft paperwork documenting part replacement in the logbook using aircraft history. I received an alert page requiring verification of on and off part number stores part numbers and manufacturer's information. All fields validating data were filled out; including providing the ipc reference and the additional comment section of which I stated the ipc reflected effectivity for all aircraft. The aircraft was dispatched for a test flight at or around XJ00; and later following a successful test flight released for revenue flight. Wdm references: 757 wdm equipment list section M00200 page 3; 757 wdm equipment identify for static inverter = M00217. Upon my arriving for third shift; I reviewed the aircraft history for aircraft X. I recognized an alert issue implying a part was deemed not effective to an aircraft. It was then I began additional research regarding this issue. I revisited the B757 ipc and came to the same conclusions as the previous day. On a hunch; I visited the 767 ipc; knowing the same inverters are used on that fleet. The 767 ipc supplement to ipc 24-33-03 provided a clear and concise detail of inverter part number and service bulletin status; and also included the engineering order addressing this service bulletin. I obtained the engineering order and learned the intent of said engineering order which was to remove certain static inverter part numbers due to poor reliability and potential failure. I then searched the engineering order database for engineering orders applicable to the 757 fleet and came up with the engineering order dated aug/xa/05 which directed the removal of the inverter part number now installed on aircraft X. I attempted to determine if the engineering order had been previously accomplished on aircraft X in the aircraft history; but was unable to come to any conclusions. With the knowledge of a reliability issue and uncertainty as to the engineering order status of aircraft X; I contacted B757 maintenance control to alert him of the issue and suggest creating a priority one note to replace the static inverter immediately with a part number acceptable to the engineering order. I later learned that; as the aircraft was out of country; an engineering authority/authorized would be issued to fly the aircraft and have the inverter replaced in ZZZ2; the first maintenance base following my discovery. 1) vague references to boeing service bulletins in the ipc supplement. 2) possibility the ipc has not beenupdated to reflect a completed engineering order. 3) unmodified parts retained in stock contrary to engineering order instructions. 4) difficulties in using aircraft history to extract data regarding modification status of aircraft. The supplement to 757 ipc 24-33-03 could be much clearer. The corresponding supplement in the 767 ipc is clear and professional in appearance. It's easy to read and draw conclusions from. It includes the connection between service bulletin number and company engineering order 2) if the service bulletin 757-24-0110 has been completed; it should be listed in the ipc service bulletin and modification list. I am unaware of any way to confirm that the engineering order has been accomplished. The engineering order must be accomplished within 40 months from the release. The deadline extends to the end of 2008. Callback conversation with reporter revealed the following information: reporter stated service bulletin 24-0110 referenced in his report addresses the overheating of the B757 and B767 static inverters. His carrier had previously issued an engineering order to purge all the pre-mod static inverters that were not modified to the service bulletin requirements. Reporter stated that even after all their efforts to verify they had installed the correct static inverter; he realized there was a problem when he later noticed their computer tracking system for parts installed to a specific aircraft indicated a record match disagree for the static inverter that was installed. Since then; his carrier has reissued the eo to check for and remove any static inverters that are pre-mod. Reporter also stated other problems associated with the static inverters have been showing up apparently after a 'cold' B757 is powered-up electrically. When the flight crews are checking recall status on their EICAS system; the static inverter senses a fault and power to the power supply modules on the E3-1 electronics equipment rack in the lower east/east center start to fall off. These affect the spoiler control modules; yaw damper module; rudder ratio changer module and stabilizer trim/elevator asymmetricalmetry limit module. They are all part of the flight control system electronic unit (cseu).

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Original NASA ASRS Text

Title: A LEAD MECHANIC REPORTS ABOUT THE DIFFICULTIES TRYING TO VERIFY THE CORRECT PART NUMBER; ACFT EFFECTIVITY; ETOPS ACCEPTABILITY AND S/B #24-0110 MODIFICATIONS ON A STATIC INVERTER REPLACEMENT FOR A B757-200.

Narrative: ACFT X REQUIRED THE STATIC INVERTER REPLACED. WORKING FROM THE 757 WDM; I OBTAINED THE PART NUMBER FROM THE EQUIP LIST VERIFYING EFFECTIVITY AND EQUIP IDENT ARRIVING AT A BOEING SPEC PART #S282T004-8. PART #S282T004-8 CROSSED IN ACFT HISTORY TO A STORES PART NUMBER; OF WHICH ZZZ1 STOCK SHOWED 1 ON HAND. UPON RECEIPT OF THE REPLACEMENT INVERTER ASSEMBLY; A DIFFERENCE IN PART NUMBERS WAS OBSERVED BTWN THE RECEIVED AND UNIT BEING REMOVED. IT WAS MY INTENTION TO HAVE MR X R&R THE INVERTER. KNOWING OF THE PART NUMBER DIFFERENCES; I SUGGESTED HE FIRST VISIT THE IPC AND CONFIGN DOCUMENTS ACCEPTABILITY TO VERIFY EFFECTIVITY AND POSSIBLE ETOPS RESTRS. HE RETURNED WITH PAGES FROM THE IPC INDICATING BOTH REMOVE AND INSTALL UNITS WERE SHOWN EFFECTIVE TO ALL ACFT. THE IPC NOMENCLATURE COLUMN REVEALED NO ETOPS RESTRS AND BOTH MANUFACTURER PART NUMBERS CROSS-IDENTED EACH OTHER THROUGH 'SVC BULLETIN OPT DATA.' A SUPPLEMENTAL PAGE WAS LINKED TO THIS IPC FIGURE WHICH LISTED VARIOUS MANUFACTURER PART NUMBERS SIMPLY IDENTING THEM AS PRE AND POST SVC BULLETIN 24-0110. OUR INSTALL UNIT WAS DETERMINED TO BE PRE SVC BULLETIN 24-0110. THE CONFIGN DOCUMENT AND ACCEPTABILITY LIST WAS CONSULTED AND REVEALED NO RESTRS FOR ANY STATIC INVERTERS FOR OUR INSTALL PART NUMBER. I TOO CONSULTED THE IPC; AND CONFIGN DOCUMENT. A REVIEW OF THE IPC SVC BULLETIN AND MODIFICATION LIST REVEALED NO SVC BULLETIN 24-0110. I CAME TO THE SAME CONCLUSIONS AS MR X REGARDING THE EFFECTIVITY OF OUR INSTALL PART NUMBER. THE UNIT WAS EFFECTIVE TO ALL ACFT WITH NO ETOPS RESTRS; AND SVC BULLETIN 24-0110 DIE NOT APPLY. AT OR ABOUT XA00 MR X INSTALLED THE INVERTER. AMM 24-33-03. I COMPLETED THE ACFT PAPERWORK DOCUMENTING PART REPLACEMENT IN THE LOGBOOK USING ACFT HISTORY. I RECEIVED AN ALERT PAGE REQUIRING VERIFICATION OF ON AND OFF PART NUMBER STORES PART NUMBERS AND MANUFACTURER'S INFO. ALL FIELDS VALIDATING DATA WERE FILLED OUT; INCLUDING PROVIDING THE IPC REF AND THE ADDITIONAL COMMENT SECTION OF WHICH I STATED THE IPC REFLECTED EFFECTIVITY FOR ALL ACFT. THE ACFT WAS DISPATCHED FOR A TEST FLT AT OR AROUND XJ00; AND LATER FOLLOWING A SUCCESSFUL TEST FLT RELEASED FOR REVENUE FLT. WDM REFS: 757 WDM EQUIP LIST SECTION M00200 PAGE 3; 757 WDM EQUIP IDENT FOR STATIC INVERTER = M00217. UPON MY ARRIVING FOR THIRD SHIFT; I REVIEWED THE ACFT HISTORY FOR ACFT X. I RECOGNIZED AN ALERT ISSUE IMPLYING A PART WAS DEEMED NOT EFFECTIVE TO AN ACFT. IT WAS THEN I BEGAN ADDITIONAL RESEARCH REGARDING THIS ISSUE. I REVISITED THE B757 IPC AND CAME TO THE SAME CONCLUSIONS AS THE PREVIOUS DAY. ON A HUNCH; I VISITED THE 767 IPC; KNOWING THE SAME INVERTERS ARE USED ON THAT FLEET. THE 767 IPC SUPPLEMENT TO IPC 24-33-03 PROVIDED A CLEAR AND CONCISE DETAIL OF INVERTER PART NUMBER AND SVC BULLETIN STATUS; AND ALSO INCLUDED THE ENGINEERING ORDER ADDRESSING THIS SVC BULLETIN. I OBTAINED THE ENGINEERING ORDER AND LEARNED THE INTENT OF SAID ENGINEERING ORDER WHICH WAS TO REMOVE CERTAIN STATIC INVERTER PART NUMBERS DUE TO POOR RELIABILITY AND POTENTIAL FAILURE. I THEN SEARCHED THE ENGINEERING ORDER DATABASE FOR ENGINEERING ORDERS APPLICABLE TO THE 757 FLEET AND CAME UP WITH THE ENGINEERING ORDER DATED AUG/XA/05 WHICH DIRECTED THE REMOVAL OF THE INVERTER PART NUMBER NOW INSTALLED ON ACFT X. I ATTEMPTED TO DETERMINE IF THE ENGINEERING ORDER HAD BEEN PREVIOUSLY ACCOMPLISHED ON ACFT X IN THE ACFT HISTORY; BUT WAS UNABLE TO COME TO ANY CONCLUSIONS. WITH THE KNOWLEDGE OF A RELIABILITY ISSUE AND UNCERTAINTY AS TO THE ENGINEERING ORDER STATUS OF ACFT X; I CONTACTED B757 MAINT CTL TO ALERT HIM OF THE ISSUE AND SUGGEST CREATING A PRIORITY ONE NOTE TO REPLACE THE STATIC INVERTER IMMEDIATELY WITH A PART NUMBER ACCEPTABLE TO THE ENGINEERING ORDER. I LATER LEARNED THAT; AS THE ACFT WAS OUT OF COUNTRY; AN ENGINEERING AUTH WOULD BE ISSUED TO FLY THE ACFT AND HAVE THE INVERTER REPLACED IN ZZZ2; THE FIRST MAINT BASE FOLLOWING MY DISCOVERY. 1) VAGUE REFS TO BOEING SVC BULLETINS IN THE IPC SUPPLEMENT. 2) POSSIBILITY THE IPC HAS NOT BEENUPDATED TO REFLECT A COMPLETED ENGINEERING ORDER. 3) UNMODIFIED PARTS RETAINED IN STOCK CONTRARY TO ENGINEERING ORDER INSTRUCTIONS. 4) DIFFICULTIES IN USING ACFT HISTORY TO EXTRACT DATA REGARDING MODIFICATION STATUS OF ACFT. THE SUPPLEMENT TO 757 IPC 24-33-03 COULD BE MUCH CLEARER. THE CORRESPONDING SUPPLEMENT IN THE 767 IPC IS CLEAR AND PROFESSIONAL IN APPEARANCE. IT'S EASY TO READ AND DRAW CONCLUSIONS FROM. IT INCLUDES THE CONNECTION BTWN SVC BULLETIN NUMBER AND COMPANY ENGINEERING ORDER 2) IF THE SVC BULLETIN 757-24-0110 HAS BEEN COMPLETED; IT SHOULD BE LISTED IN THE IPC SVC BULLETIN AND MODIFICATION LIST. I AM UNAWARE OF ANY WAY TO CONFIRM THAT THE ENGINEERING ORDER HAS BEEN ACCOMPLISHED. THE ENGINEERING ORDER MUST BE ACCOMPLISHED WITHIN 40 MONTHS FROM THE RELEASE. THE DEADLINE EXTENDS TO THE END OF 2008. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED SERVICE BULLETIN 24-0110 REFERENCED IN HIS REPORT ADDRESSES THE OVERHEATING OF THE B757 AND B767 STATIC INVERTERS. HIS CARRIER HAD PREVIOUSLY ISSUED AN ENGINEERING ORDER TO PURGE ALL THE PRE-MOD STATIC INVERTERS THAT WERE NOT MODIFIED TO THE SERVICE BULLETIN REQUIREMENTS. REPORTER STATED THAT EVEN AFTER ALL THEIR EFFORTS TO VERIFY THEY HAD INSTALLED THE CORRECT STATIC INVERTER; HE REALIZED THERE WAS A PROBLEM WHEN HE LATER NOTICED THEIR COMPUTER TRACKING SYSTEM FOR PARTS INSTALLED TO A SPECIFIC ACFT INDICATED A RECORD MATCH DISAGREE FOR THE STATIC INVERTER THAT WAS INSTALLED. SINCE THEN; HIS CARRIER HAS REISSUED THE EO TO CHECK FOR AND REMOVE ANY STATIC INVERTERS THAT ARE PRE-MOD. REPORTER ALSO STATED OTHER PROBLEMS ASSOCIATED WITH THE STATIC INVERTERS HAVE BEEN SHOWING UP APPARENTLY AFTER A 'COLD' B757 IS POWERED-UP ELECTRICALLY. WHEN THE FLIGHT CREWS ARE CHECKING RECALL STATUS ON THEIR EICAS SYSTEM; THE STATIC INVERTER SENSES A FAULT AND POWER TO THE POWER SUPPLY MODULES ON THE E3-1 ELECTRONICS EQUIPMENT RACK IN THE LOWER E/E CENTER START TO FALL OFF. THESE AFFECT THE SPOILER CONTROL MODULES; YAW DAMPER MODULE; RUDDER RATIO CHANGER MODULE AND STAB TRIM/ELEVATOR ASYMMETRICALMETRY LIMIT MODULE. THEY ARE ALL PART OF THE FLIGHT CONTROL SYSTEM ELECTRONIC UNIT (CSEU).

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.