What color should the humidity indicator on the PBE be during a preflight check?

The humidity indicator on a Protective Breathing Equipment (PBE) should be blue during a preflight check. A blue indicator signifies that the equipment is in good condition and has not been exposed to humidity, which is crucial for functionality.

If the indicator shows a different color such as red, green, or yellow, it may indicate moisture exposure or that the PBE is not ready for use. An incorrect color could compromise the safety of the equipment and the effectiveness of the breathing apparatus in an emergency situation. Therefore, ensuring that the indicator is blue is essential for confirming that the PBE is reliable and safe to use in case of smoke or fire onboard.