What altitude triggers the amber [CKPT ALT] annunciator?

The amber [CKPT ALT] annunciator is triggered when the cabin altitude exceeds a specific threshold, which is set to alert the crew about potential cabin pressure issues. In this case, the correct threshold is 19,000 feet.

When the altitude reaches this level, it indicates that the cabin is at risk of not being properly pressurized, which can lead to hypoxia or other altitude-related complications for the passengers and crew. It serves as a safety mechanism to ensure that the crew is aware of the situation and can take corrective action if necessary, such as descending to a lower altitude or initiating emergency procedures.

This level is set according to the design and operational guidelines for the aircraft, ensuring that pilots are notified well before reaching any critical limits, thus supporting safety and operational effectiveness in the cockpit.