What is the first warning indicated by the CPAM sequence at 8500 feet?

The first warning indicated by the Cabin Pressure and Altitude Monitoring (CPAM) sequence at 8500 feet is the CABIN ALT CAUTION. This caution alert is crucial as it notifies the crew that the cabin altitude has reached a level where the pressure difference between the cabin and the outside air may start to pose a risk to passenger safety and comfort.

At this altitude, the system is designed to provide an early warning to allow adequate time for flight crew to assess the situation. The CABIN ALT CAUTION serves as an informative precursor to higher urgency warnings, which will follow if the situation does not improve or if cabin altitude rises significantly beyond normal operating levels. This systematic approach helps ensure that any necessary actions can be taken promptly, mitigating risks associated with cabin pressurization issues.

Understanding this hierarchy of warnings is essential for effective decision-making and maintaining safety protocols in flight operations.