What is verified during the preflight check of the O2 tool?

During the preflight check of the O2 tool, verifying the very presence of the tool is essential for safety and operational efficiency. This means confirming that the O2 tool is actually available and in the designated location, ensuring that it can be accessed quickly in case of an emergency. The presence of the O2 tool allows crew members to respond effectively to any issues related to oxygen supply and to assist those who may require supplemental oxygen during flight.

While other aspects such as expiration date, connection integrity, and functionality are also important checks to be performed on equipment, the initial step is to ensure that the tool is physically there. Without the O2 tool being present, any further checks or validations become irrelevant since the crew would not have access to the necessary equipment. Therefore, confirming the presence is a critical component of ensuring readiness for any emergencies that may arise during operations.