PSU stands for?

• A. Primary Service Unit
• B. Passenger Service Unit
• C. Power Supply Unit
• D. Passenger System Unit

Answer: (B)

In airline cabin terminology, PSU stands for Passenger Service Unit. This is the panel installed above each passenger seat that provides individual amenities and controls—typically the reading light, air vent, and the passenger call button, and it commonly houses the oxygen mask compartment as part of the unit. It’s specific to the passenger cabin experience and is not about electrical power supplies or a “primary” service function, which is why the other terms don’t fit. On a Boeing 737-700, you’ll see a PSU above each seat, delivering these essential passenger controls in one integrated unit.