What is the procedure for preflighting oxygen compartments?

The procedure for preflighting oxygen compartments includes ensuring that the RED indicator is NOT visible. This is a crucial step because the visibility of the RED indicator typically signifies that there is a problem with the oxygen system, such as an issue with the flow of oxygen or that the system is not ready for use. Ensuring this indicator is not visible helps confirm that the oxygen supply is in good working order and ready for emergency situations if needed.

While checking for expired oxygen tanks, testing the oxygen flow, and inspecting for physical damage are all important aspects of safety checks, the specific focus on the RED indicator is a key component of the preflight procedure directly related to the operational readiness of the oxygen supply. This makes it a primary focus in ensuring passenger and crew safety during flight operations.