Narrative:

During shim removal from the first day, we were using a G-8 to hammer out shims, and driving wedges up in the casters as far as it would go (titanium) then beat the wedge out. I think damage and undue stress have occurred but to what extent is unknown because of accessibility. Callback conversation with reporter revealed the following information: the reporter stated the engineering change order required a check of the mid bulkhead aluminum shims to check for migration. The reporter said if migration was found, the shims must be replaced with stainless steel shims. The reporter stated the engineering change order required use of a large rivet gun to drive a titanium wedge between the bulkhead and the engine mount forging thus creating a gap to allow the aluminum shim to be removed. The reporter said the job required 3 days with all 3 shifts for each pylon and when driving the titanium wedges it would cut into the surface metal of the bulkhead creating unseen damage. The reporter stated after 4 airplanes had the change order completed, the change order was stopped due to possible structural pylon damage. The reporter stated the 4 airplanes will be routed back again for inspection.

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Original NASA ASRS Text

Title: TOTAL OF 4 B757-200 ACFT MAY HAVE INCURRED PYLON STRUCTURAL DAMAGE DURING ACCOMPLISHMENT OF AN ENGINEERING CHANGE ORDER.

Narrative: DURING SHIM REMOVAL FROM THE FIRST DAY, WE WERE USING A G-8 TO HAMMER OUT SHIMS, AND DRIVING WEDGES UP IN THE CASTERS AS FAR AS IT WOULD GO (TITANIUM) THEN BEAT THE WEDGE OUT. I THINK DAMAGE AND UNDUE STRESS HAVE OCCURRED BUT TO WHAT EXTENT IS UNKNOWN BECAUSE OF ACCESSIBILITY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ENGINEERING CHANGE ORDER REQUIRED A CHK OF THE MID BULKHEAD ALUMINUM SHIMS TO CHK FOR MIGRATION. THE RPTR SAID IF MIGRATION WAS FOUND, THE SHIMS MUST BE REPLACED WITH STAINLESS STEEL SHIMS. THE RPTR STATED THE ENGINEERING CHANGE ORDER REQUIRED USE OF A LARGE RIVET GUN TO DRIVE A TITANIUM WEDGE BTWN THE BULKHEAD AND THE ENG MOUNT FORGING THUS CREATING A GAP TO ALLOW THE ALUMINUM SHIM TO BE REMOVED. THE RPTR SAID THE JOB REQUIRED 3 DAYS WITH ALL 3 SHIFTS FOR EACH PYLON AND WHEN DRIVING THE TITANIUM WEDGES IT WOULD CUT INTO THE SURFACE METAL OF THE BULKHEAD CREATING UNSEEN DAMAGE. THE RPTR STATED AFTER 4 AIRPLANES HAD THE CHANGE ORDER COMPLETED, THE CHANGE ORDER WAS STOPPED DUE TO POSSIBLE STRUCTURAL PYLON DAMAGE. THE RPTR STATED THE 4 AIRPLANES WILL BE ROUTED BACK AGAIN FOR INSPECTION.

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.