What is the purpose of the Passenger Service Unit (PSU) in an aircraft?

The purpose of the Passenger Service Unit (PSU) in an aircraft is to hold the customer ventilation system and controls. This component is crucial for providing comfort to passengers during the flight. The PSU typically includes individual air vents that allow passengers to control the flow of air directly to their seating area, as well as lights and call buttons for assistance.

By allowing passengers to adjust their ventilation, the PSU contributes to a more pleasant cabin environment, which is essential for long flights where passenger comfort is a priority. This function directly impacts the overall passenger experience, making the PSU an integral part of the cabin's service infrastructure.