On July 16, 1999, John Kennedy, Jr. died when the plane he was piloting crashed into the Atlantic Ocean off Martha's Vineyard.

Experts suspect Kennedy was a victim of what's called the graveyard spiral, which is what happens when a pilot engages in a downward spiral after losing his the ability to judge the orientation of the aircraft. It can happen to any pilots, including very well-trained ones, because in certain situations the inner ear can cause disorientation.

Specialists at Mayo Clinic in the Aerospace Medicine and Vestibular Research Laboratory are developing tools to help pilots and others who work in extreme environments to stay safe.

"The body is unfortunately easily tricked. We've been designed to walk, not to fly," said Dr. Jan Stepanek, Director of the Aerospace Medicine Program at Mayo Clinic. "Our lab primarily focuses on three areas; acceleration, high altitudes, as well as spatial disorientation and prevention of problems with special disorientation."

Stepanek's team uses a chair to simulate what happens to the body when a pilot spins in flight. A slow, downward spiral is one of the most common situations, and can result in a crash. This can happen to people who are extremely experienced because the sensation is so powerful.

By learning what happens to the body as it spins in the dynamic chair, Dr. Stepanek is developing ways to help pilots avoid deadly situations. He also uses a human centrifuge to study the effects of G-forces on the body.

When a plane flies very quickly and pulls a turn, G-forces start to act on the people inside the aircraft. That means the heart has to work harder to maintain blood flow to the brain and, if that doesn't happen, then people can black out.

Dr. Stepanek's work enhances what's called the anti-G-force maneuver, which was developed at Mayo during World War II.

During the Anti-G Straining Maneuver, people tense their muscles in a sequence and breathe in a certain fashion to maximize the blood pressure and maintain blood flow to the brain. This helps researchers studying how motion effects the body.

In addition to Stepanek's research on G-forces and disorientation, the team is also working on ways to combat motion sickness, altitude sickness, and other issues that come up in extreme environments.

For more information on spatial disorientation, you can go to the Mayo Clinic's website or can call the Mayo Clinic in Jacksonville at 904-953-2272.