What is the TUC at 28,000 feet?

The correct answer, 18 seconds, refers to the Time of Useful Consciousness (TUC) at an altitude of 28,000 feet, which is a critical concept in aviation physiology. TUC is the duration one can maintain consciousness after experiencing a rapid decompression or loss of cabin pressure, without supplemental oxygen.

At 28,000 feet, the partial pressure of oxygen is significantly reduced, leading to hypoxia—the lack of sufficient oxygen to the brain and body. Studies and data indicate that at this altitude, a person typically has around 18 seconds of useful consciousness before they start experiencing impairments due to hypoxia. This limited time emphasizes the urgency for pilots and crew to receive supplemental oxygen or initiate an emergency descent to ensure safety and prevent impaired decision-making.

Understanding TUC is essential for those involved in aviation and emergency response scenarios, as it directly influences protocols for rapid descent and the deployment of oxygen systems during in-flight emergencies or decompression events.