Date: 201901
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Training / Qualification
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural MEL / CDL
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Maintenance Action
Contributing factors: Manuals; Procedure; Logbook Entry; MEL; Human Factors
Primary problem: MEL

Narrative: This [report] has three parts: a deferral that was done incorrectly; a sign-off that doesn't reflect reality; and an MEL (Minimum Equipment List) card that contains incorrect information.The right thrust reverser was deferred under MEL [Number] on log page [Number]. The maintenance procedure calls for two breakers to be pulled and collared: the 'R ENG SYNC-LOCK or R ENG SYNC-LOCK CONT' on the P11 panel and the 'R ENG SYNC-LOCK ALTN or R ENG SYNC-LOCK CONT ALTN' on the P6 panel. However; Maintenance pulled and collared the wrong breaker on the P11 panel. They pulled breaker B-30; labeled 'Right T/R CONT ALT'; when they should have pulled breaker K-32; labeled 'SYNC LOCK'. Attached picture 'P11-1' shows the correct breaker (collared); and attached picture 'P11-2' shows the incorrect breaker (after the collar was removed).I asked a local mechanic who was in the cockpit for other work to check these breakers against the MEL. He said they were correct. I called [Maintenance Control] for a second opinion. [Maintenance Control] said they were incorrect and said he would send local maintenance back to the aircraft. I then made a write-up (log page [Number]) about the incorrect breaker being pulled and collared. A different mechanic came back to the cockpit at that point and corrected the breakers.However; when they signed off my log entry about the incorrect breakers being pulled; they entered the corrective action as 'verified correct CB (Circuit Breaker) for MEL'. This is false. They did not verify that the correct breakers were pulled; because the correct breakers were not pulled. This sign-off implies they did the procedure correctly in the first place; and that's not true. The local maintenance controller even told us on the radio 'nice catch.' Sign-offs need to reflect actual work performed; but this one appears to be an attempt to hide the fact that a mistake was made on the initial deferral.That brings me to the MEL card itself. The instructions say the breaker on the P6 panel is labeled 'R ENG SYNC-LOCK ALTN or R ENG SYNC-LOCK CONT ALTN'; but that's not what the labeling says in the airplane. See attached picture P6-1. The actual labeling is 'R ENG SYNC LOCK (BAT BUS)'. So the MEL card is incorrect here. I also believe that this contributed to the mistake that maintenance made in the initial deferral as described above. Because the breaker labeling on the P6 panel ends is 'BAT BUS' instead of 'ALTN'; I think they were still searching for something that said 'ALTN' or 'ALT' and that led them to pull the wrong breaker on the P11 panel.My suggestion for preventing these sorts of issues is to have the MEL state exact grid location for the breakers instead of generic labeling. I understand this may be problematic because grid locations can vary among aircraft of the same type; but that would still be a better system than something that results in the wrong breaker being pulled and collared in a deferral.




Synopsis: B757 Captain reported maintenance pulled the wrong circuit breakers per MEL deferral procedure.