What is the time of useful consciousness at 25,000 feet?

The time of useful consciousness at an altitude of 25,000 feet is typically around 2 to 5 minutes. This refers to the period during which a person can maintain cognitive function and perform necessary tasks effectively after a loss of cabin pressure.

At this altitude, the partial pressure of oxygen decreases to a level that may lead to hypoxia, impairing one's ability to think clearly and perform critical functions. This range of 2 to 5 minutes is reflective of how the human body reacts to lower oxygen availability; it gives enough time for properly trained individuals to take appropriate actions, such as setting an emergency descent or donning supplemental oxygen if available. Thus, understanding this critical period is vital for safety in aviation contexts.