What should be done if the humidity dot on the PBE is not blue?

The correct course of action when the humidity dot on the Protective Breathing Equipment (PBE) is not blue is to replace the device immediately. The humidity indicator is a critical safety feature designed to show that the PBE has remained in a usable condition. If the dot is not blue, it indicates that the equipment may have been compromised, potentially leading to a failure in providing the necessary protection in an emergency situation.

Immediate replacement ensures that the crew has access to functional equipment, which is essential for safety during operations. PBE is crucial for providing breathable air in smoke or toxic gas environments, and using compromised equipment could jeopardize the safety of the crew and passengers.

Continuing with other preflight checks or reporting the issue without replacing the PBE could put lives at risk if an emergency arises and the equipment cannot be relied upon. Similarly, using the equipment only if necessary does not address the immediate issue of having potentially faulty safety equipment. Hence, the protocol is to replace it as soon as the humidity indicator shows any sign of being ineffective.