What is the time of useful consciousness at an altitude of 40,000 feet?

At an altitude of 40,000 feet, the time of useful consciousness is typically around 18 seconds. This value represents the duration a person can remain conscious and able to function effectively after exposure to rapid decompression or loss of cabin pressure, before physiological effects such as hypoxia (lack of oxygen) significantly impair cognitive and physical capabilities. Understanding the time of useful consciousness is crucial in aviation safety, as it informs crew members about the critical time available for effective responses to emergencies, such as donning oxygen masks and initiating emergency procedures. This knowledge helps in promoting a timely and efficient emergency response, thus enhancing overall safety on board.