Limited visibility is the single greatest contributing factor in most fatal worldwide airline and general aviation crashes. In commercial aviation, over 30% of all fatal accidents are categorized as controlled flight into terrain accidents (CFIT). A CFIT accident usually occurs at night or in bad weather when a normally functioning aircraft flies into a mountainside or other obstacle because the pilot doesn't realize the plane is headed in the wrong direction. Another major accident category affecting flights in the U.S. is called a runway incursion, in which an aircraft on the ground comes into contact with another plane or object on the runway. Many of these accidents may be prevented thanks to a revolutionary new cockpit display system currently being developed by NASA. Working with the aeronautics industry, NASA is developing a virtual reality display system called Synthetic Vision.

Synthetic Vision combines the Global Positioning Systems (GPS), terrain databases, and graphical displays to create a three-dimensional scene of what the pilot should be seeing outside the plane. The only difference between this "synthetic" view and the "real world" is that every day is "picture perfect." It's clear skies always, even in the worst weather conditions, for pilots using synthetic vision.

The GPS identifies the aircraft's position. Based upon this information, the synthetic vision software searches through terrain databases to pull together a map of this location. As the aircraft's position changes, the map changes, too. The pilot sees an accurate, 3D-moving display in the cockpit.

Dozens of pilots have already tested this technology. During the flight evaluations, the test pilots' windshields were often intentionally covered or flights were conducted at night. Low visibility conditions were simulated so pilots would be forced to rely on the computer-generated information on the displays. So far, these pilots have been thrilled by the results. "I think it's awesome," said Rick Shay, a United Airlines 767 captain. "To explain the difference in the situational awareness that you gain, it's just a complete leap from the technology that's there."

The information the pilot sees may be displayed in different ways. One, a head-down display (HDD), is mounted in the plane's instrument panel. The HDD is not transparent but is bigger and more detailed. The images displayed on the HDD are photo quality, down to the trees on the mountains.

A second display, the heads-up display (HUD), superimposes the images onto a screen that is located in front of the pilots' eyes. This screen is transparent and is similar to the displays fighter pilots use. The HUD is monochromatic -- everything in shades of green -- and displays only outlines and shading.

This amazing technology has the potential to drastically improve safety for pilots. Imagine a world where it is always clear and sunny.