PSU stands for which of the following?

• A. Passenger Service Unit
• B. Passenger System Unit
• C. Passage System Unit
• D. Portable Oxygen System

Answer: (C)

PSU stands for Passenger Service Unit. This overhead panel above each seat houses controls and features that passengers use during a flight—air vents, a reading light, the passenger call button, and information signs. In an emergency, the same unit houses the emergency oxygen system, and the masks drop down from there. The other phrases aren’t the standard term used for this cabin component—there isn’t a commonly used “Passenger System Unit” or “Passage System Unit,” and “Portable Oxygen System” refers to a different, portable setup rather than the fixed PSU above the seat.