Narrative:

We pushed back from gate. After completing the after start flow and just before calling for the before taxi checklist, we experienced a left wing body overheat indication. I called for the checklist for the left wing body overheat, which the first officer completed. Somehow in the process, we completely missed note #5 in the QRH and ended up on note #6 thinking we could dispatch. We then completed the before taxi checklist and taxied clear of the ramp area to a spot where we could hold without blocking traffic. I then directed my first officer to contact dispatch via ACARS. I looked at MEL 26 concerning the left wing body overheat. I failed to recognize that MEL 26-12 is for a failed warning system. In my mind, I thought we were complying with the intent of the MEL and that we were good to go. The ACARS was slow, so I contacted dispatch by company radio and was given a release per MEL 26-12. After takeoff, we got an ACARS message from dispatch to return to the gate. We sent a message back that we were airborne and then received a message back to disregard the return to gate message. In our next city, I contacted dispatch to finish processing the aircraft logbook and MEL 26-12. After review with dispatch and maintenance, my error became apparent and clear. In conclusion: considering that there were 4 or 5 people involved in this event that missed note #5 requiring a return to the gate, possibly the QRH and/or the MEL could be worded differently. Supplemental information from acn 616580: using the technology of ACARS, we communicated our situation with dispatch. The process was quite time consuming as we punched out multiple messages and waited for a response. The captain finally just contacted dispatch via the radio. At initial radio contact, dispatch had finished consulting with maintenance and had an MEL for us to continue operation. We made proper notation and proceeded to runway 25R. On departure, we had a failure of the automatic pressurization system and completed the automatic fail checklist. The pressurization was working normally in the standby mode until descent into ZZZ1. At approximately 9000 ft, the cabin pressure began to climb rapidly to 7000 ft and we went to manual mode to correct the pressure. At the gate, the captain called maintenance on the phone. Maintenance now said the MEL they gave us to operate under did not address our specific problem. I believe the cause of this errant MEL was simple communication. While the ACARS is nice, it is difficult to convey detailed problems with accuracy and complete comprehension by both parties. In the future, if the situation requires more than simple dialog, then I will communicate with dispatch or maintenance via radio. I will also scrutinize an MEL received from dispatch or maintenance to verify it is the proper one.

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Original NASA ASRS Text

Title: AFTER CONFERENCE WITH DISPATCH AND MAINT COORD, AN ILLEGAL MEL ADJUSTMENT IS MADE BY A B737-300 FLT CREW TO A L WING BODY OVERHEAT INDICATION PRIOR TO DEP.

Narrative: WE PUSHED BACK FROM GATE. AFTER COMPLETING THE AFTER START FLOW AND JUST BEFORE CALLING FOR THE BEFORE TAXI CHKLIST, WE EXPERIENCED A L WING BODY OVERHEAT INDICATION. I CALLED FOR THE CHKLIST FOR THE L WING BODY OVERHEAT, WHICH THE FO COMPLETED. SOMEHOW IN THE PROCESS, WE COMPLETELY MISSED NOTE #5 IN THE QRH AND ENDED UP ON NOTE #6 THINKING WE COULD DISPATCH. WE THEN COMPLETED THE BEFORE TAXI CHKLIST AND TAXIED CLR OF THE RAMP AREA TO A SPOT WHERE WE COULD HOLD WITHOUT BLOCKING TFC. I THEN DIRECTED MY FO TO CONTACT DISPATCH VIA ACARS. I LOOKED AT MEL 26 CONCERNING THE L WING BODY OVERHEAT. I FAILED TO RECOGNIZE THAT MEL 26-12 IS FOR A FAILED WARNING SYS. IN MY MIND, I THOUGHT WE WERE COMPLYING WITH THE INTENT OF THE MEL AND THAT WE WERE GOOD TO GO. THE ACARS WAS SLOW, SO I CONTACTED DISPATCH BY COMPANY RADIO AND WAS GIVEN A RELEASE PER MEL 26-12. AFTER TKOF, WE GOT AN ACARS MESSAGE FROM DISPATCH TO RETURN TO THE GATE. WE SENT A MESSAGE BACK THAT WE WERE AIRBORNE AND THEN RECEIVED A MESSAGE BACK TO DISREGARD THE RETURN TO GATE MESSAGE. IN OUR NEXT CITY, I CONTACTED DISPATCH TO FINISH PROCESSING THE ACFT LOGBOOK AND MEL 26-12. AFTER REVIEW WITH DISPATCH AND MAINT, MY ERROR BECAME APPARENT AND CLR. IN CONCLUSION: CONSIDERING THAT THERE WERE 4 OR 5 PEOPLE INVOLVED IN THIS EVENT THAT MISSED NOTE #5 REQUIRING A RETURN TO THE GATE, POSSIBLY THE QRH AND/OR THE MEL COULD BE WORDED DIFFERENTLY. SUPPLEMENTAL INFO FROM ACN 616580: USING THE TECHNOLOGY OF ACARS, WE COMMUNICATED OUR SIT WITH DISPATCH. THE PROCESS WAS QUITE TIME CONSUMING AS WE PUNCHED OUT MULTIPLE MESSAGES AND WAITED FOR A RESPONSE. THE CAPT FINALLY JUST CONTACTED DISPATCH VIA THE RADIO. AT INITIAL RADIO CONTACT, DISPATCH HAD FINISHED CONSULTING WITH MAINT AND HAD AN MEL FOR US TO CONTINUE OP. WE MADE PROPER NOTATION AND PROCEEDED TO RWY 25R. ON DEP, WE HAD A FAILURE OF THE AUTO PRESSURIZATION SYS AND COMPLETED THE AUTO FAIL CHKLIST. THE PRESSURIZATION WAS WORKING NORMALLY IN THE STANDBY MODE UNTIL DSCNT INTO ZZZ1. AT APPROX 9000 FT, THE CABIN PRESSURE BEGAN TO CLB RAPIDLY TO 7000 FT AND WE WENT TO MANUAL MODE TO CORRECT THE PRESSURE. AT THE GATE, THE CAPT CALLED MAINT ON THE PHONE. MAINT NOW SAID THE MEL THEY GAVE US TO OPERATE UNDER DID NOT ADDRESS OUR SPECIFIC PROB. I BELIEVE THE CAUSE OF THIS ERRANT MEL WAS SIMPLE COM. WHILE THE ACARS IS NICE, IT IS DIFFICULT TO CONVEY DETAILED PROBS WITH ACCURACY AND COMPLETE COMPREHENSION BY BOTH PARTIES. IN THE FUTURE, IF THE SIT REQUIRES MORE THAN SIMPLE DIALOG, THEN I WILL COMMUNICATE WITH DISPATCH OR MAINT VIA RADIO. I WILL ALSO SCRUTINIZE AN MEL RECEIVED FROM DISPATCH OR MAINT TO VERIFY IT IS THE PROPER ONE.

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.