{{Short description|Aircraft component}} {{More citations needed|date=March 2026}} thumb|PECO Passenger Service Unit for the Boeing 737 A '''passenger service unit''' ('''PSU''') is an aircraft component situated above each row in the overhead panel above the passenger seats in the cabin of airliners. Among other things, a PSU contains reading lights, loudspeakers for announcements, illuminated signs (to remind people that the cabin is a no-smoking zone and to wear a seatbelt), buttons to call for assistance (though these are mounted on the armrest on some aircraft), air condition vents, and automatically deployed oxygen masks in case of cabin depressurisation.<ref>{{cite web |title=Master Minimum Equipment List (MMEL) Guidance Book |url=https://tc.canada.ca/sites/default/files/2023-07/master-minimum-equipment-list-mmel-guidance-book.pdf |website=Transport Canada |publisher=Government of Canada |date=July 2023 |format=PDF |language=en |access-date=2026-03-01 }}</ref>
May be absent or simplified on the smallest regional aircraft or on some very early-generation airliners <ref>{{cite web |title=Passenger Service Unit (PSU) |url=https://skybrary.aero/articles/passenger-service-unit-psu |website=SKYbrary Aviation Safety |publisher=EUROCONTROL / Aviation Safety Network |access-date=2026-03-01 }}</ref> thumb|Oxygen masks deployed from a PSU
==References== {{reflist}}
{{Aircraft components}}
Category:Safety equipment Category:Aircraft cabin components
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