What should be checked to ensure the PBE is operational during a preflight check?

When conducting a preflight check for the Protective Breathing Equipment (PBE), it is essential to ensure that the seals of the unit are intact. The integrity of these seals is crucial for the PBE to function correctly. If the seals are compromised, the equipment may not provide the necessary protection in a smoke or toxic gas environment, which could jeopardize the safety of the flight attendants and passengers.

The presence of smoke would not typically be checked during a preflight inspection, as operational checks should be performed under normal conditions. Similarly, while the color indicators on PBE may provide some information about its condition, the primary focus during inspections should be on the physical condition of the equipment itself, specifically the seals, to ensure it is ready for use if needed. The emphasis on checking the seals as part of the operational readiness highlights the importance of having fully functional equipment in emergency situations, ensuring that it will provide optimal protection when required.