Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Workload; Fatigue; Distraction
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC complied w / Automation / Advisory
Human Factors
Captain had a Vmo (Max Operating Speed) exceedance after leveling off from a climb in a clean configuration at 8;000 ft MSL. The alarm and I notified him and he corrected by reducing power and slowing down. The filed altitude for the flight was 7;000 [feet] but due to terrain we had to climb to 8;000 [feet]. The change to the flight plan and what we briefed on the ground caused distractions between MFD display; ATC instructions/communications; [and] flying the plane and aircraft control.  This was during leg 5 of a 5 leg day and we were in our 12th duty hour.The cause of this exceedance I believe is due to the lack of experience the captain has with this aircraft and the challenging operations at [Company]. The lessons I learned from this is to be more vigilant with monitoring the Pilot Flying during high workload and transitions. Example; leveling off from a climb.
Air carrier flight crew reported aircraft encountered Maximum Speed exceedance in cruise.