What does the cabin rate of climb indicator display?

The cabin rate of climb indicator displays the rate of change in cabin altitude, which is an essential aspect of monitoring the conditions within an aircraft as it changes altitude. This indicator provides information about how rapidly the cabin altitude is increasing or decreasing, which is particularly important during ascent and descent phases of flight.

Understanding this rate is crucial for aircrew as it helps them manage passenger comfort, ensure compliance with safety regulations, and maintain appropriate pressure levels within the cabin to avoid physiological effects on the occupants. Monitoring the rate of change allows crew members to respond effectively to any issues related to cabin pressure or altitude changes.

The other choices pertain to different aspects of the cabin environment. Cabin pressure levels are managed through other instruments, temperature changes are monitored by environmental control systems, and noise levels are assessed using sound measurement tools, none of which are the specific focus of the cabin rate of climb indicator.