NORAD says crashed aircraft was flying erratically.

Washington - US military officials say a small, single engine plane crashed near Muncie, Indiana, after operating erratically. They said they believe the pilot, who was the only person on the plane, had been suffering from a lack of oxygen.

A spokesman for US Northern Command said that military officials do not believe it is terrorism related. Instead, Michael Kucharek said the pilot may have blacked out due to a condition known as hypoxia.

The FAA reports the six-year-old plane, a Mooney M20, took off from Grand Rapids, Michigan. It is registered to a company based in Ada, Michigan.

The plane was flying at 25,000 feet when Grand Rapids control lost radio contact with the pilot and called for military assistance to make a visual contact.

At around 9:30 am, F-16 fighters under the direction of North American Aerospace Defense Command intercepted the aircraft.

SEE THE FLIGHT TRACK OF THIS AIRCRAFT HERE

"It was creating a situation where he would speed up, slow down, change course. He was flying in a southerly direction but he was flying erratically," said John Erickson, Indiana Department of Homeland Security.

Erickson said the pilots in the escort planes saw that the pilot was disoriented at first, then unresponsive. The F-16 pilots reported that the pilot was slumped over the yoke.

"It was steadily losing altitude and they were reporting that as it happened," said Erickson.

According to the Indiana Guard, the escorts came from the Ohio Air Guard.

The crash occurred in a Randolph County farm field approximately a half-mile west of State Road 1 and about 1,000 feet south of State Road 28. State Road 28 is closed at the crash scene.

The NTSB will be handling the investigation. The pilot's condition is not known at this time.

Kucharek said the plane was heading south-southeast and had been speeding up and slowing down to dangerous speeds. Law enforcement was on the scene.

Initially there was some concern that the plane was headed towards Indianapolis and that it might crash somewhere on North Keystone, a busy thoroughfare.

The intent of military intercepts is to identify aircraft, re-establish communications with local FAA air traffic controllers and instruct the pilot to follow air traffic controllers to land safely for further follow-on action.

NORAD's mission - in close collaboration with homeland defense, security, and law enforcement partners - is to prevent air attacks against North America, safeguard the sovereign airspaces of the United States and Canada by responding to unknown, unwanted and unauthorized air activity approaching and operating within these airspaces, and provide aerospace and maritime warning for North America.

NORAD may be required to monitor, shadow, divert from flight path, direct to land and/or destroy platforms deemed a potential threat to North America.

NORAD is the bi-national Canadian and American command that is responsible for the air defense of North America and maritime warning. The command has three subordinate regional headquarters: the Alaskan NORAD Region at Elmendorf Air Force Base, Alaska; the Canadian NORAD Region at Winnipeg, Manitoba; and the Continental NORAD Region at Tyndall Air Force Base, Fla. The command is poised both tactically and strategically in our nation's capital to provide a multilayered defense to detect, deter and prevent potential threats flying over the airspace of the United States and Canada.