Tonight the mystery of a small plane that caused a scare near Washington D.C. Before plunging into the ocean. What happened to the pilot? Why did he stop responding? ABC's Clayton Sandell with that... See More
Tonight the mystery of a small plane that caused a scare near Washington D.C. Before plunging into the ocean. What happened to the pilot? Why did he stop responding? ABC's Clayton Sandell with that story. Reporter: The coast guard is suspending the search for a small plane that took off Saturday from Wisconsin flying to Virginia. But instead of landing, it continued on through restricted air space around Washington D.C., when the pilot no longer responds to radio calls, two f-16 fighters scramble. They can see the pilot appears unconscious. About 50 miles over the ocean, the plane runs out of fuel and goes down. What a horrible feeling for these air force pilots to watch this airplane obviously flying out to its demise out to sea. And not being able to do anything to help. Reporter: The pilot identified as Ronald Hutchinson. It is not clear why he passed out. There are all sorts of things that could go wrong. You could have problems with the airplane, if you fly too high and don't have oxygen, you become hypoxic, your brain runs out of oxygen. And ceases to function. Reporter: That's what happened in 2008 to the crew flying a small jet. Unable. To control. Altitude. We think he has hypoxia. Reporter: This crash comes at a time the federal government and pilots who fly planes like these are dealing with a safety record, that is far more dangerous than flying commercial. Last year, nearly 450 people died in small plane crashes, just today in Erie, Colorado, another crash. Three people did not survive. Adding to a deadly total, that pilots and the federal government agree is flying far too high. Clayton Sandell, ABC news, centennial, Colorado.
This transcript has been automatically generated and may not be 100% accurate.