Narrative:

Called just before departure to report that during the preflight fire warning test the warning light in the right engine fuel cut-off switch would not test. All other system test indications were normal for both engines; the APU; cargo fire and wheel well fire. As I recall the light worked normally during the flight deck 'lights' test; as reported by the crew. Realizing that this was an unusual problem which would likely encounter a significant delay; I looked into MEL 26-11-01. At the time I decided that this MEL was more restrictive than necessary and was thus safe to use. It wasn't until the next day that I realized that when I used this MEL I was considering the affected engine side instead of an affected loop. (MEL 26-11-01 addresses specific loops inoperative; not engines affected.) I incorrectly issued a flight crew placard to defer the item. The next day; when I realized what I had done incorrectly; the aircraft was stopped until fixed. Supplemental information from acn 689688: during preflight; first flight of the day items; fire warning check; I discovered the right fuel control switch light was inoperative. I called maintenance and told them exactly what I had as a discrepancy. They gave me an MEL number and a control number and instructed me to flight crew placard it.

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Original NASA ASRS Text

Title: B757 FLT CREW IS ISSUED AN MEL BY MAINT CTL FOR AN INOP FIRE WARNING INDICATOR LIGHT. THE IMPROPER MEL IS ISSUED.

Narrative: CALLED JUST BEFORE DEP TO RPT THAT DURING THE PREFLT FIRE WARNING TEST THE WARNING LIGHT IN THE R ENG FUEL CUT-OFF SWITCH WOULD NOT TEST. ALL OTHER SYS TEST INDICATIONS WERE NORMAL FOR BOTH ENGS; THE APU; CARGO FIRE AND WHEEL WELL FIRE. AS I RECALL THE LIGHT WORKED NORMALLY DURING THE FLT DECK 'LIGHTS' TEST; AS RPTED BY THE CREW. REALIZING THAT THIS WAS AN UNUSUAL PROB WHICH WOULD LIKELY ENCOUNTER A SIGNIFICANT DELAY; I LOOKED INTO MEL 26-11-01. AT THE TIME I DECIDED THAT THIS MEL WAS MORE RESTRICTIVE THAN NECESSARY AND WAS THUS SAFE TO USE. IT WASN'T UNTIL THE NEXT DAY THAT I REALIZED THAT WHEN I USED THIS MEL I WAS CONSIDERING THE AFFECTED ENG SIDE INSTEAD OF AN AFFECTED LOOP. (MEL 26-11-01 ADDRESSES SPECIFIC LOOPS INOP; NOT ENGS AFFECTED.) I INCORRECTLY ISSUED A FLT CREW PLACARD TO DEFER THE ITEM. THE NEXT DAY; WHEN I REALIZED WHAT I HAD DONE INCORRECTLY; THE ACFT WAS STOPPED UNTIL FIXED. SUPPLEMENTAL INFO FROM ACN 689688: DURING PREFLT; FIRST FLT OF THE DAY ITEMS; FIRE WARNING CHK; I DISCOVERED THE R FUEL CTL SWITCH LIGHT WAS INOP. I CALLED MAINT AND TOLD THEM EXACTLY WHAT I HAD AS A DISCREPANCY. THEY GAVE ME AN MEL NUMBER AND A CTL NUMBER AND INSTRUCTED ME TO FLT CREW PLACARD IT.

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.