What happens when the cockpit altitude exceeds 19,000 feet?

When the cockpit altitude exceeds 19,000 feet, a warning message is displayed. This alert is a crucial safety feature designed to inform the pilots that they are surpassing a specific altitude threshold where supplemental oxygen may be required due to the reduced atmospheric pressure and oxygen availability.

This warning serves as a prompt for the crew to ensure their oxygen systems are utilized, thus enhancing the safety of the flight and preventing potential hypoxia, which can occur at high altitudes when oxygen levels are insufficient for normal physiological functioning. The presence of this alert is an important aspect of the aircraft's safety management system, ensuring that pilots are continually aware of their operational environment and can take the necessary measures to maintain safe flight conditions.

The other options indicate conditions that do not align with the aircraft's operational responses at high altitudes. For instance, while the oxygen system may indeed need to be activated, the lack of a direct warning message at that altitude does not accurately reflect the systems in place for monitoring cockpit altitude. Hence, the display of a warning message is the correct and expected outcome in this scenario.