A B747-200 WAS DISPATCHED AND OPERATED FOR 6 DAYS IN NON COMPLIANCE WITH THE INCORRECT #2 ENG EXHAUST GAS TEMP INDICATOR INSTALLED.

Narrative

ON AUG/XA/01 THE AIR CREW ON ACFT WERE PERFORMING THEIR PREFLT INSPECTION. UPON INSPECTING; THE CREW FOUND THE #2 ENG EGT DIGITAL INDICATOR BLANK. THE CREW CONTACTED MAINT VIA VHF RADIO WHICH I RESPONDED BY ASKING WHAT THE PROB WAS. WHEN I WAS TOLD WHAT THE MALFUNCTION WAS; I PROCEEDED TO GO TO OUR PARTS SHELF AND FOUND A DIGITAL EGT INDICATOR IN STOCK. I TOOK THE PART OUT TO THE ACFT AND PROCEEDED TO TROUBLESHOOT THE MALFUNCTION. UPON COMPLETION OF TROUBLESHOOTING; I FOUND THAT THE #2 ENG EGT INDICATOR WAS AT FAULT. I REPLACED THE INDICATOR WITH THE ONE FROM STOCK; WHICH BOTH INDICATORS LOOK IDENTICAL EXCEPT FOR THE DIFFERENT RANGE MARKINGS. I PERFORMED THE OPS CHK WHICH WAS NORMAL THEN PERFORMED THE CORRECTIVE ACTION IN THE ACFT LOGBOOK WHICH IN TIME SHORTLY AFTER THAT THE ACFT DEPARTED THE GATEWAY ON TIME. THE ACFT FLEW SCHEDULE FLTS WITH NO DISCREPANCIES ON THE #2 ENG EGT SYS UNTIL ON AUG/THU/01. ACFT WAS INBOUND TO ANC WHEN THE FLC NOTICED THE #2 ENG EGT INDICATOR HAD DIFFERENT RANGE MARKINGS. THE #2 ENG EGT INDICATOR WAS A B747-100 INDICATOR (JT90-7A) NOT A B747-200 INDICATOR (JT9D-7Q). THE CREW NOTIFIED MAINT AND WROTE UP THE #2 ENG EGT INDICATOR BEING A -100 INDICATOR IN THE ACFT LOGBOOK. THE MECH WORKING THE ACFT REPLACED THE INDICATOR WITH THE PROPER INDICATOR AND CLRED THE MAINT DISCREPANCY IN THE ACFT LOGBOOK.