Narrative:

While working with another mechanic on MEL procedure locking out left thrust reverser the wrong circuit breaker was collared resulting in a status message after takeoff. The flight continued on without further incident. The rest of the MEL procedure was complied with. Supplemental information from acn 790544: aircraft rtb due to 'left engine rev cont' EICAS message. As lead on duty I assigned 2 amt's to defer the left thrust reverser. I prepared the deferral entry into the maintenance CPU as the work progressed. Upon conferring with the amt's involved I completed the entry. I later received a phone call from line maintenance control that the circuit breaker pulled for the deferral was incorrect and had caused another message; 'left oil scvg' upon takeoff. The aircraft continued on its trip. Supplemental information from acn 790545: the aircraft came back to the gate with a left engine rev cont status message. We conferred with maintenance control and he advised us to lock out the left thrust reverser per the MEL procedures. We were trying to do this as safely as possible but also we were working in a time sensitive manner. We read and reread the MEL but it is very lengthy and can be somewhat confusing. One of the last procedures is to lock out a circuit breaker for the sync lock on the P6-2 panel. As I entered the flight deck I looked up on the P11 panel for the breaker thinking it was there; the D12 breaker is a cont breaker which matched the status message we had; somewhat; and this is what I believed was the correct breaker. Thinking we had followed the MEL procedure correctly; we released the aircraft. We learned later; that the crew got a scavenge cont status message after takeoff and continued on to their destination. The rest of the MEL procedure was accomplished per the MEL correctly.

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Original NASA ASRS Text

Title: A LEAD AND TWO MECHANICS REPORT ON LOCKING OUT THE LEFT ENGINE THRUST REVERSER ON A B757-200 ACFT; BUT PULLED AND COLLARED THE WRONG CIRCUIT BREAKER; RESULTING IN A 'LEFT OIL SCVG' MESSAGE AFTER TKOF.

Narrative: WHILE WORKING WITH ANOTHER MECH ON MEL PROC LOCKING OUT L THRUST REVERSER THE WRONG CIRCUIT BREAKER WAS COLLARED RESULTING IN A STATUS MESSAGE AFTER TKOF. THE FLT CONTINUED ON WITHOUT FURTHER INCIDENT. THE REST OF THE MEL PROC WAS COMPLIED WITH. SUPPLEMENTAL INFO FROM ACN 790544: ACFT RTB DUE TO 'L ENG REV CONT' EICAS MESSAGE. AS LEAD ON DUTY I ASSIGNED 2 AMT'S TO DEFER THE L THRUST REVERSER. I PREPARED THE DEFERRAL ENTRY INTO THE MAINT CPU AS THE WORK PROGRESSED. UPON CONFERRING WITH THE AMT'S INVOLVED I COMPLETED THE ENTRY. I LATER RECEIVED A PHONE CALL FROM LINE MAINT CTL THAT THE CIRCUIT BREAKER PULLED FOR THE DEFERRAL WAS INCORRECT AND HAD CAUSED ANOTHER MESSAGE; 'L OIL SCVG' UPON TKOF. THE ACFT CONTINUED ON ITS TRIP. SUPPLEMENTAL INFO FROM ACN 790545: THE ACFT CAME BACK TO THE GATE WITH A L ENG REV CONT STATUS MESSAGE. WE CONFERRED WITH MAINT CTL AND HE ADVISED US TO LOCK OUT THE L THRUST REVERSER PER THE MEL PROCS. WE WERE TRYING TO DO THIS AS SAFELY AS POSSIBLE BUT ALSO WE WERE WORKING IN A TIME SENSITIVE MANNER. WE READ AND REREAD THE MEL BUT IT IS VERY LENGTHY AND CAN BE SOMEWHAT CONFUSING. ONE OF THE LAST PROCS IS TO LOCK OUT A CIRCUIT BREAKER FOR THE SYNC LOCK ON THE P6-2 PANEL. AS I ENTERED THE FLT DECK I LOOKED UP ON THE P11 PANEL FOR THE BREAKER THINKING IT WAS THERE; THE D12 BREAKER IS A CONT BREAKER WHICH MATCHED THE STATUS MESSAGE WE HAD; SOMEWHAT; AND THIS IS WHAT I BELIEVED WAS THE CORRECT BREAKER. THINKING WE HAD FOLLOWED THE MEL PROC CORRECTLY; WE RELEASED THE ACFT. WE LEARNED LATER; THAT THE CREW GOT A SCAVENGE CONT STATUS MESSAGE AFTER TKOF AND CONTINUED ON TO THEIR DEST. THE REST OF THE MEL PROC WAS ACCOMPLISHED PER THE MEL CORRECTLY.

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.