What is included in the PBE operation procedures?

The correct choice highlights the importance of ensuring a secure fit for the neck seal of the PBE (Protective Breathing Equipment). This step is crucial as a proper fit is essential for maximizing the effectiveness of the equipment in protecting the user from smoke and toxic gases. A secure neck seal prevents conditions that could lead to contamination inside the PBE, thus ensuring the integrity of the breathing air supply and enhancing the overall safety of the crew member using it during an emergency.

In the context of PBE operation procedures, checking the neck seal is often emphasized in training and operational guidelines as it directly impacts the safety and performance of the equipment. Failing to secure the neck seal, on the other hand, can lead to inadequate protection, potentially putting the user at risk.

While the other choices may involve actions that can be common in handling or utilizing safety equipment, they do not focus on this critical aspect of ensuring an effective, protective seal vital for the PBE's function.