Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification
Aircraft
Due to aircraft vent avionics system fault (lack of pressurization); we returned to ZZZ resulting in an overweight landing. Always have the return or plan of action in the secondary flight plan; it really benefited us to be ready tonight.
Air carrier crew reported a pressurization problem on departure; resulting in a return to the departure airport and an overweight landing.