How is oxygen flow activated on the BE Aerospace PBE?

Oxygen flow on the BE Aerospace Portable Breathing Equipment (PBE) is activated by grasping the adjustment straps and pulling them forward. This action serves to initiate the mechanism that allows oxygen to flow to the user. The design is intended for quick accessibility and ease of use during emergency situations, where rapid response is critical.

The other options involve mechanisms common in various equipment but do not apply to the activation method for the PBE. Twisting a valve or pressing a lever may indicate other devices’ operations but are not part of the design for this particular PBE model. Similarly, a start button might be found in electronic devices but is not relevant here. The focus on adjustment straps reflects the need for a simple, user-friendly activation method in emergency scenarios.