passenger service unit

A passenger service unit (PSU) is an aircraft component situated above each row in the overhead panel above the passenger

seats A seat is a place to sit. The term may encompass additional features, such as back, armrest, head restraint but also headquarters in a wider sense. Types of seat The following are examples of different kinds of seat: * Armchair, a chair equ ...

in the cabin of

airliner An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ...

s. Among other things, a PSU contains reading lights,

loudspeakers A loudspeaker (commonly referred to as a speaker or speaker driver) is an Acoustical engineering#Electroacoustics, electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often ...

for announcements, illuminated signs (to remind people that the aircraft is a no-smoking zone and to wear a

seatbelt A seat belt (also known as a safety belt, or spelled seatbelt) is a vehicle safety device designed to secure the driver or a passenger of a vehicle against harmful movement that may result during a collision or a sudden stop. A seat belt red ...

), buttons to call for assistance (though these are mounted on the armrest on some aircraft),

air condition Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...

vents, and automatically deployed oxygen masks in case of cabin depressurisation. These are not found on the smallest of feederliners, or on older aircraft. Safety equipment Aircraft cabin components {{aviation-stub