When will the aircrew member resume breathing after removing the mask?

Resuming breathing after removing the mask is contingent upon the aircrew member reaching a safe and controlled environment, which is indicated by getting to Area 4—Station 2. This location is specifically designated for such procedures, ensuring that it is safe for the aircrew member to breathe normally without the mask on. Transitioning back to normal breathing can involve the need for a period of recovery, particularly after exposure to altitude or situations that may have required mask usage due to hypoxia or other factors.

In contrast, removing the mask immediately does not consider the need to ensure that environmental conditions are safe for normal respiration. Waiting for a specified period before breathing normally might not apply as aircrew members are trained to transition effectively based on their environment rather than an arbitrary time frame. Being back on the aircraft would typically indicate the end of flight operations but does not necessarily mean the aircrew has reached a safe point to resume normal breathing, especially if they are still at altitude or engaging in procedures that could affect their oxygen levels. Thus, reaching Area 4—Station 2 is the crucial step in ensuring the aircrew's safety and readiness to breathe normally again.