Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Software and Automation; MEL; Human Factors; Aircraft
The aircraft flown had 2 MELs which could not be flown with together; XX-YY-01-1 and XX-YY-02-1. Consecutively these were DU4 Inop and MCDU 1 inop. The Captain and I did not catch the discrepancy and flew the flight without consequence. [I suggest a] more thorough briefing of MELs.
First Officer reported that the aircraft was operated with two open MELs that were not authorized for operation together.