Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Flight Instructor
Flight Crew Last 90 Days 250; Flight Crew Total 6700; Flight Crew Type 1100
Communication Breakdown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Incorrect / Not Installed / Unavailable Part
The right FO (First Officer) display dimmer was written up. As a result of this replaced CDU/MEL (Control Display Unit/Minimum Equipment list) 34-XX-XX.Captain side CDU IPL (Illustrated Parts List) Part number XXXXXXXX-X; the FO side Part number XXXXXX-Y.[Days later] another write up made with regards to the CDU's being different from one another and that key strokes that were bringing up different pages when selected. These were noted deficient on both Captain and FO side CDU; due to them being different units. Maintenance deferred the item per MEL 34-XX-XX-XX stating that FO side only button command was intermittent. Again during flight it was noted that the boxes were not talking to each other properly and key strokes were faulty. The item was re-written up by Captain and once again brought Maintenance personnel attention. When reporting to aircraft flight personnel stressed the fact that we needed the CDU to be either removed and replaced with matching CDU so they talk with each other or to de-energize and collar the breaker supplying power to the unit and operate single CDU allowed by the MEL 34-XX-XX-XX. Flight crew was insured that part would be available when we arrived in ZZZ and would be replaced. After arrival into ZZZ we were told that the part had been sent to the ZZZ1 base. The aircraft currently has two different CDU installed but at least the FO side has been de-energized and removed from service.
B757 Captain reported a repeating Control Display Unit malfunction followed by improper Maintenance action.