A gasper is an aviation term referring to the adjustable air outlet situated above each passenger seat. These outlets are part of the aircraft's air conditioning and cabin air recirculation system and may feature adjustments for both direction and strength of air flow. They are typically round vents situated above passenger seating with a flow control dial and, in some cases, a directional nozzle. In older aircraft, these outlets were fed directly from the aircraft's packs or air conditioners. In newer planes, the gaspers are fed from the air recirculation system.
The cabins of pressurized passenger aircraft are maintained at a pleasant temperature and supplied with a constant supply of fresh air by several air conditioning units known as packs. This air flow is achieved through a series of strategically placed inlet and outlet vents. Each passenger seating position is, however, also equipped with a supplemental ventilation supply for increased personal comfort. These ventilation points are known as gaspers and can be adjusted by the passenger to supply more or less air flow or be closed off altogether. In some cases, a clamshell nozzle can also be adjusted to change the direction of air flow.
Gasper outlets are fed by a fan or fans which feature a master control on the flight deck overhead air conditioning panel. These outlets feed supplemental air flow to the passengers during ground operations and in flight but may be turned off during takeoffs and landings. This procedure is meant to maximize bleed air availability; as soon as the initial part of the climb-out is complete, the packs and recirculation or gasper fans switch back on.
Older aircraft such as the Boeing 737 100 and 200 series featured gasper systems fed directly from the aircraft's air conditioners. A gasper fan boosted pack air through a series of risers and ducts to the passenger outlets. This fan was usually used during periods of high pack demand and low system pressure. These gasper fans supplied much needed additional fresh air on very hot days while the aircraft was still on the ground.
Newer aircraft feature gaspers which receive their air supply from the cabin recirculation system. This system constantly removes, filters, and recirculates cabin air. This process reduces the bleed air requirements and pack loads, thus increasing performance and lowering fuel consumption. In either case, the passengers receive a source of additional ventilation to ensure comfort during the flight.