Cabinedruk

Cabinedruk, or cabin pressure, refers to the controlled air pressure inside the cabin of an aircraft. It maintains a safe and comfortable environment for passengers and crew during flight by offsetting the low ambient pressure at cruise altitude.

The cabin is supplied and conditioned by the environmental control system (ECS). Bleed air from the engines or an auxiliary power unit is cooled or heated, mixed to the desired temperature, and introduced into the cabin. Pressurization is achieved by sealing the cabin and using an outflow valve and a cabin pressure controller to maintain a target cabin altitude and differential pressure between cabin and outside air. Sensors monitor the pressure and adjust flow automatically to keep values within approved limits.

Typical values: at cruise altitude, outside air is at roughly 30,000–40,000 feet, while the cabin is pressurized to about 6,000–8,000 feet. The differential pressure between the cabin and exterior generally remains in the range of about 7–9 psi, depending on aircraft type and flight conditions. Modern airliners are designed to maintain these conditions across a wide range of scenarios.

Safety and emergencies: sudden loss of cabin pressure is a defined hazard. In decompression, oxygen masks deploy for passengers and crew; crew members often use quick-don oxygen equipment. The onboard oxygen systems provide breathable air for a limited period while procedures re-establish safe cabin conditions or the aircraft descends to a breathable altitude.

Maintenance and regulation: pressurization systems undergo regular checks and certification. Key components include the outflow valve, pressure relief valves, cabin altitude indicators, and associated controls. Standards are established by aviation authorities such as the FAA and EASA.