When implementing the Cargo Fire Suppression Rule of 3, what is required for a non-annunciated fire?

When addressing the Cargo Fire Suppression Rule of 3 for a non-annunciated fire, the requirement is to press the button once. This action activates the fire suppression system, allowing the crew to respond to a potential cargo fire without requiring confirmation from a warning system, as it does not provide an explicit indication of a fire. The Rule of 3 is designed to ensure a quick, decisive action in the event of a fire, reflecting the urgency to manage such critical situations effectively.

Consequently, pressing the button once is sufficient to begin the necessary suppression measures, acknowledging that the crew is taking proactive steps without waiting for further indications or signals. This minimizes potential delays in response time during an emergency situation.