By David Shepardson
WASHINGTON Four people, including the pilot, were killed in Sunday's crash of a light plane that caused a security scare when it flew over heavily restricted airspace near Washington, authorities said on Monday.
Investigators do not yet know why the plane was on that flight path after the pilot became unresponsive, the National Transportation Safety Board (NTSB) said.
The Department of Defense scrambled F-16 fighter jets, which created a sonic boom over the U.S. capital as they pursued the Cessna Citation 560 that crashed in southwest Virginia.
The Federal Aviation Administration confirmed on Monday that four people were killed in the crash, without identifying them. There were no survivors, Virginia State Police said.
NTSB investigator Adam Gerhardt said the wreckage was highly fragmented and in heavily wooded, rural mountainous terrain that made it "a very challenging accident site." The NTSB will remove wreckage and move it to a secure location in Delaware.
"Basically everything is on the table," Gerhardt said of the investigation. "The airplane, the engines, the weather conditions, pilot qualifications, the maintenance records — all aspects will be of course items we routinely look at."
The Cessna was not required to have a flight data recorder or cockpit voice recorder, NTSB said.
A U.S. official said the fighter jets did not cause the crash.
The Cessna was registered to Encore Motors of Melbourne, Florida, according to FAA flight records.
Encore owner John Rumpel told the Washington Post his daughter, a grandchild and her nanny were on board.
The U.S. military attempted to contact the pilot, who was unresponsive, North American Aerospace Defense Command (NORAD) said in a statement. Military pilots also used flares in an attempt to get the pilot's attention.
The Cessna appeared to be flying on autopilot, another source familiar with the matter said.
The Cessna took off from Elizabethton Municipal Airport in Elizabethton, Tennessee, and was bound for Long Island MacArthur Airport in New York, about 50 miles (80 km) east of Manhattan, the FAA said.
(Reporting by David Shepardson; Editing by Lisa Shumaker and Rosalba O'Brien)