A B777 R ENG WAS BORESCOPED AND DIGITAL PICTURE OF THE HIGH PRESSURE BLADE WAS COMPARED TO MAINT MANUAL CHART AND FOUND WITHIN LIMITS. LATER DISCOVERED BLADE OUT OF LIMITS. SHEET #2 OF CHART WAS NOT REFED.

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THE INSPECTOR THAT PERFORMED THE BORESCOPE ON THE #2 ENG OF THE B777 ACFT AND GAVE ME THE MAINT MANUAL REF HE WAS USING FOR THE DAMAGE HE HAD FOUND DURING BORESCOPE INSPECTION OF #2 ENG. HE HAD AN ILLUSTRATION OF THE HPC BLADE. THIS ILLUSTRATION HAD 3 ZONES IDENTED ON THE BLADE (A; B; AND C). WITH THE MAINT MANUAL REF AND THE DIGITAL PICTURES HE HAD TAKEN OF THE DAMAGE WE DETERMINED THAT THE DAMAGE WAS WITHIN LIMITS AND COULD CONTINUE IN SVC WITH A REINSPECT BORESCOPE CYCLE. WE HAVE JUST LEARNED THAT WE HAD USED THE WRONG REF FOR OUR DAMAGE ASSESSMENT. WHEN YOU REF THE DAMAGE VERBIAGE IN THE MAINT MANUAL; IT REFS FIGURE X WHICH GIVES A SNAPSHOT OF THE BLADE AREAS; A; B; ETC. UNDER HPC #1 IT REFS FIGURE X AND WHEN YOU CLICK ON IT YOU GET AN ILLUSTRATION OF THE BLADE. UNDER HPC #2 THROUGH #6 THEY GIVE YOU THE SAME REF AND WHEN YOU CLICK ON IT YOU GET THE SAME ILLUSTRATION AGAIN. WHAT YOU DON'T NOTICE IS THAT THERE IS A SHEET #1 AND A SHEET #2. THIS INFO IS SOMEWHAT HIDDEN. I AM SUBMITTING A RFS (REVISION CHANGE OR CORRECTION) TO CHANGE SHEET #2 OF FIGURE X TO ITS OWN FIGURE NUMBER; SUCH AS FIGURE XX FOR HPC BLADES #2 THROUGH #6. THE BOTTOM LINE IS DUE TO THIS OVERSIGHT WE THOUGHT THE DAMAGE WAS WITHIN LIMITS WHEN IN FACT IT IS NOT. THE ACFT IS SCHEDULED IN FOR AN ENG CHANGE. SUPPLEMENTAL INFO FROM ACN 635148: I REQUESTED MY SUPVR SUBMIT A CHANGE TO THE COMPUTERIZED MAINT MANUAL TO PREVENT THIS ERROR FROM HAPPENING AGAIN. ENGINEERING NOTICED THE DISCREPANCY AND SCHEDULED AN ENG CHANGE.