Narrative:

Aircraft came in with log write-ups 'flag in view continuously on tat indicator' and 'flag in view continuously on maximum EPR indicator.' I went into cockpit and checked out to see if cbs were popped. Recycled cbs, no help. No parts were available at station. According to the MEL manual tat/EPR indicator EPR function is deferrable. Going down the line on the right side column I read what I had to do to defer it and came to a paragraph that referred medium large transport type 3. Since that did not apply I was done and entered deferral into computer. Gate mechanic tried to get release but could not since one more item was still open. I was told to put ok on 'action taken' and to write 'see deferral log 2 item.' line maintenance called my foreman about illegal deferral while the plane was still on the fields. I also talked to line maintenance and explained what the write-ups were. Aircraft left to its destination and was allowed to depart from there also west/O line maintenance or anyone else stopping it or taking corrective action. Flight was scheduled to go to a different station but was diverted back to the station where it departed from with the illegal deferral. The flight crew discovered that tat/EPR was not operating. Being a mechanic I had no way of stopping the plane after finding out about the illegal deferral from line maintenance. I expected them to take corrective action. After line maintenance called I checked the MEL manual again and found out that I had deferred tat indicator that was 'no-go' item. In my opinion, the way MEL manual is written it has a big pit fall: tat function is placed under medium large transport type 3 note even though it applies to medium large transport type 2 also. Tat function should be listed first since it is required for flight and is not deferrable.

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Original NASA ASRS Text

Title: ACR MLG WAS USED IN COMMERCIAL OPERATION WITHOUT COMPLYING WITH MINIMUM EQUIPMENT LIST REQUIREMENT.

Narrative: ACFT CAME IN WITH LOG WRITE-UPS 'FLAG IN VIEW CONTINUOUSLY ON TAT INDICATOR' AND 'FLAG IN VIEW CONTINUOUSLY ON MAX EPR INDICATOR.' I WENT INTO COCKPIT AND CHKED OUT TO SEE IF CBS WERE POPPED. RECYCLED CBS, NO HELP. NO PARTS WERE AVAILABLE AT STATION. ACCORDING TO THE MEL MANUAL TAT/EPR INDICATOR EPR FUNCTION IS DEFERRABLE. GOING DOWN THE LINE ON THE R SIDE COLUMN I READ WHAT I HAD TO DO TO DEFER IT AND CAME TO A PARAGRAPH THAT REFERRED MLG TYPE 3. SINCE THAT DID NOT APPLY I WAS DONE AND ENTERED DEFERRAL INTO COMPUTER. GATE MECH TRIED TO GET RELEASE BUT COULD NOT SINCE ONE MORE ITEM WAS STILL OPEN. I WAS TOLD TO PUT OK ON 'ACTION TAKEN' AND TO WRITE 'SEE DEFERRAL LOG 2 ITEM.' LINE MAINT CALLED MY FOREMAN ABOUT ILLEGAL DEFERRAL WHILE THE PLANE WAS STILL ON THE FIELDS. I ALSO TALKED TO LINE MAINT AND EXPLAINED WHAT THE WRITE-UPS WERE. ACFT LEFT TO ITS DEST AND WAS ALLOWED TO DEPART FROM THERE ALSO W/O LINE MAINT OR ANYONE ELSE STOPPING IT OR TAKING CORRECTIVE ACTION. FLT WAS SCHEDULED TO GO TO A DIFFERENT STATION BUT WAS DIVERTED BACK TO THE STATION WHERE IT DEPARTED FROM WITH THE ILLEGAL DEFERRAL. THE FLT CREW DISCOVERED THAT TAT/EPR WAS NOT OPERATING. BEING A MECH I HAD NO WAY OF STOPPING THE PLANE AFTER FINDING OUT ABOUT THE ILLEGAL DEFERRAL FROM LINE MAINT. I EXPECTED THEM TO TAKE CORRECTIVE ACTION. AFTER LINE MAINT CALLED I CHKED THE MEL MANUAL AGAIN AND FOUND OUT THAT I HAD DEFERRED TAT INDICATOR THAT WAS 'NO-GO' ITEM. IN MY OPINION, THE WAY MEL MANUAL IS WRITTEN IT HAS A BIG PIT FALL: TAT FUNCTION IS PLACED UNDER MLG TYPE 3 NOTE EVEN THOUGH IT APPLIES TO MLG TYPE 2 ALSO. TAT FUNCTION SHOULD BE LISTED FIRST SINCE IT IS REQUIRED FOR FLT AND IS NOT DEFERRABLE.

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.