What does a rapidly flashing one red light on the SCBA HUD indicate?

A rapidly flashing one red light on the SCBA Heads-Up Display (HUD) signifies that the air supply in the cylinder has reached a critical level, specifically at or around the 1/4 cylinder air supply mark. This is an important alert for firefighters, as it indicates that they need to prepare for air supply management and consider exiting or refilling the SCBA cylinder soon.

In the context of firefighter safety and operational readiness, recognizing this alert is crucial as it ensures that personnel are aware of their air status, allowing for timely decision-making. The flashing red light serves as a clear visual cue, emphasizing the urgency to address dwindling air resources during firefighting operations or rescue missions.