Narrative:

Returned to gate for left 'filter bypass' light on fuel panel. Company maintenance instructed contract maintenance to change filter. No obstructions/contamination noted on old filter. Started #1 engine at gate; and filter bypass light illuminated at just above idle power after 1 min. Contacted dispatch to MEL light. Wrote up in logbook as 'left filter bypass light illuminated after start.' released with MEL 79. On taxi out; light extinguished 5 mins into taxi. Light re-illuminated after landing in ZZZ. During flight; realized; MEL 79 was for the oil filter bypass; MEL 73 was for the fuel filter bypass. ZZZ maintenance met aircraft to correct MEL (thinking it was only the wrong MEL applied). I wanted to break the chain of events; so I asked company maintenance to contact contract maintenance in our departing city to ensure that the fuel filter was changed and inspected per MEL 73. Contract maintenance said he changed and inspected the oil filter. I told ZZZ maintenance; company maintenance; and oncoming captain what had happened; and aircraft was taken OTS for inspection. 1) fatigue. I should have caught the incorrect MEL. I read it multiple times and was not rushed; but had woke up at XA00 today (XB30 wake-up prior day; 12 hour duty and 10-hour overnight; hotel next to freeway; etc; last night). 2) the fuel panel light reads 'filter bypass.' on the -700; there is no actual 'oil filter bypass' light; but a 'virtual' yellow box on the center mfd display reading 'oil filter bypass' (not normally visible). I did not even consider this light during the MEL discussion. Supplemental information from acn 772703: it was apparent that there was a misunderstanding in communication and an inappropriate oil 'filter bypass' deferral was issued. It wasn't until we pushed back and departed that I reviewed the paperwork and MEL and noticed the error. After arriving in ZZZ; maintenance control was notified and the problem was corrected. Supplemental information from acn 773812: while working the -700 desk in maintenance control; I received a call from dispatch that aircraft X was returning to the gate. I asked the dispatcher why; and I believe he said #1 oil filter bypass light. A few moments later the captain called and I believe I said 'I hear you have an oil filter bypass light;' and he said yes. I told him to get operations to call contract maintenance that we would pull the oil filter; replace it and continue per MEL 79 if old filter was clean and problem was in indication circuit. He said ok. Contract maintenance did just that; put a sticker on the inside cover of the logbook and one at the top of the center display unit. I gave him a tracking number and the aircraft left with MEL 79 assigned. Upon arriving at destination; captain called and said the MEL was wrong; he had a fuel bypass light -- not an oil bypass light. I said; 'captain; did you or did you not tell me it was an oil bypass indication?' he said he did not know. Maintenance replaced the fuel filter and differential pressure switch and cleared the MEL. No contamination was found in the filter.

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Original NASA ASRS Text

Title: A B737-700 FLIGHT CREW AND MAINT CONTROLLER DESCRIBE THE CONFUSION AND MISCOMMUNICATION SURROUNDING THE RELEASE OF THEIR ACFT WITH AN INCORRECT MEL AND THE FUEL FILTER BYPASS LIGHT NOT RESOLVED.

Narrative: RETURNED TO GATE FOR L 'FILTER BYPASS' LIGHT ON FUEL PANEL. COMPANY MAINT INSTRUCTED CONTRACT MAINT TO CHANGE FILTER. NO OBSTRUCTIONS/CONTAMINATION NOTED ON OLD FILTER. STARTED #1 ENG AT GATE; AND FILTER BYPASS LIGHT ILLUMINATED AT JUST ABOVE IDLE PWR AFTER 1 MIN. CONTACTED DISPATCH TO MEL LIGHT. WROTE UP IN LOGBOOK AS 'L FILTER BYPASS LIGHT ILLUMINATED AFTER START.' RELEASED WITH MEL 79. ON TAXI OUT; LIGHT EXTINGUISHED 5 MINS INTO TAXI. LIGHT RE-ILLUMINATED AFTER LNDG IN ZZZ. DURING FLT; REALIZED; MEL 79 WAS FOR THE OIL FILTER BYPASS; MEL 73 WAS FOR THE FUEL FILTER BYPASS. ZZZ MAINT MET ACFT TO CORRECT MEL (THINKING IT WAS ONLY THE WRONG MEL APPLIED). I WANTED TO BREAK THE CHAIN OF EVENTS; SO I ASKED COMPANY MAINT TO CONTACT CONTRACT MAINT IN OUR DEPARTING CITY TO ENSURE THAT THE FUEL FILTER WAS CHANGED AND INSPECTED PER MEL 73. CONTRACT MAINT SAID HE CHANGED AND INSPECTED THE OIL FILTER. I TOLD ZZZ MAINT; COMPANY MAINT; AND ONCOMING CAPT WHAT HAD HAPPENED; AND ACFT WAS TAKEN OTS FOR INSPECTION. 1) FATIGUE. I SHOULD HAVE CAUGHT THE INCORRECT MEL. I READ IT MULTIPLE TIMES AND WAS NOT RUSHED; BUT HAD WOKE UP AT XA00 TODAY (XB30 WAKE-UP PRIOR DAY; 12 HR DUTY AND 10-HR OVERNIGHT; HOTEL NEXT TO FREEWAY; ETC; LAST NIGHT). 2) THE FUEL PANEL LIGHT READS 'FILTER BYPASS.' ON THE -700; THERE IS NO ACTUAL 'OIL FILTER BYPASS' LIGHT; BUT A 'VIRTUAL' YELLOW BOX ON THE CTR MFD DISPLAY READING 'OIL FILTER BYPASS' (NOT NORMALLY VISIBLE). I DID NOT EVEN CONSIDER THIS LIGHT DURING THE MEL DISCUSSION. SUPPLEMENTAL INFO FROM ACN 772703: IT WAS APPARENT THAT THERE WAS A MISUNDERSTANDING IN COM AND AN INAPPROPRIATE OIL 'FILTER BYPASS' DEFERRAL WAS ISSUED. IT WASN'T UNTIL WE PUSHED BACK AND DEPARTED THAT I REVIEWED THE PAPERWORK AND MEL AND NOTICED THE ERROR. AFTER ARRIVING IN ZZZ; MAINT CTL WAS NOTIFIED AND THE PROB WAS CORRECTED. SUPPLEMENTAL INFO FROM ACN 773812: WHILE WORKING THE -700 DESK IN MAINT CTL; I RECEIVED A CALL FROM DISPATCH THAT ACFT X WAS RETURNING TO THE GATE. I ASKED THE DISPATCHER WHY; AND I BELIEVE HE SAID #1 OIL FILTER BYPASS LIGHT. A FEW MOMENTS LATER THE CAPT CALLED AND I BELIEVE I SAID 'I HEAR YOU HAVE AN OIL FILTER BYPASS LIGHT;' AND HE SAID YES. I TOLD HIM TO GET OPS TO CALL CONTRACT MAINT THAT WE WOULD PULL THE OIL FILTER; REPLACE IT AND CONTINUE PER MEL 79 IF OLD FILTER WAS CLEAN AND PROB WAS IN INDICATION CIRCUIT. HE SAID OK. CONTRACT MAINT DID JUST THAT; PUT A STICKER ON THE INSIDE COVER OF THE LOGBOOK AND ONE AT THE TOP OF THE CTR DISPLAY UNIT. I GAVE HIM A TRACKING NUMBER AND THE ACFT LEFT WITH MEL 79 ASSIGNED. UPON ARRIVING AT DEST; CAPT CALLED AND SAID THE MEL WAS WRONG; HE HAD A FUEL BYPASS LIGHT -- NOT AN OIL BYPASS LIGHT. I SAID; 'CAPT; DID YOU OR DID YOU NOT TELL ME IT WAS AN OIL BYPASS INDICATION?' HE SAID HE DID NOT KNOW. MAINT REPLACED THE FUEL FILTER AND DIFFERENTIAL PRESSURE SWITCH AND CLRED THE MEL. NO CONTAMINATION WAS FOUND IN THE FILTER.

Data retrieved from NASA's ASRS site as of May 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.