is a physiological condition brought on by a lack of oxygen going to the body tissues including the brain. to the crash of a aircraft in Virginia on Sunday, which caused the deaths of four people, including a toddler, according to .

The plane, which was supposed to travel from Tennessee to Long Island, NY, overshot its destination before swinging towards Washington, D.C., flying over the capitol at upwards of 34,000 feet. It’s unlikely that anyone was alive at that time, as the plane was unresponsive to repeated attempts at communication, and authorized to go supersonic to catch the small passenger jet.

The plane’s pilot, Jeff Hefner, was observed as being slumped over by F-16 pilots before the plane eventually crashed into a densely wooded area in Virginia. At the plane’s 34,000-foot altitude, a person has just 30-60 seconds to put on an oxygen mask before losing consciousness.

If the pilot and passengers did black out and eventually suffocate, the plane’s avionics would likely keep it in the air until it ran out of fuel and the heading change could be attributed to the pilot programming a flight path based on . Determining the exact cause of the crash will be difficult because, according to FAA investigators, the densely forested crash site tore the plane apart to the point that it’s essentially unrecognizable.

The owner of the plane, Jim Rumpel, worked with the FAA to contact the plane, which went out of communication around 15 minutes into its flight. The passenger jet was being flown by Hefner, an experienced commercial pilot. The three passengers included Rumpel’s daughter, Adina Azarian, her two-year-old granddaughter Aria Azarian, and a nanny.