Four people, including a pilot and three passengers, were killed in a plane crash that prompted officials to place the U.S. Capitol complex on alert Sunday afternoon.
State of play: Federal investigators said they expect to be at the scene for several days to determine why the plane went off course and collided into a mountain.
What we know: A sonic boom rang out across the D.C. region as fighter aircraft responded to an unresponsive pilot flying a Cessna.
- NORAD said it deployed an F-16 fighter jet to intercept the plane, which the Federal Aviation Administration reported was carrying four people before it later crashed in mountainous terrain near Montebello, Va.
- State and local law enforcement reached the crash site by foot just before 8pm after an hourslong search in the Staunton-Blue Ridge Parkway area, per an emailed statement from Virginia State Police spokesperson Corinne Geller late Sunday.
- "No survivors were located," she said.
- The FAA and the National Transportation Safety Board are both investigating the incident that saw startled residents across the region post on social media about hearing a "loud explosion" as the sonic boom occurred.
Zoom in: The incident prompted D.C. Homeland Security and Emergency Management to tweet just after 3:30pm: "We are aware of reports from communities throughout the National Capital Region of a loud 'boom' this afternoon. There is no threat at this time."
- Officials in Maryland said the boom was caused by an authorized Defense Department plane out of Joint Base Andrews, where President Biden was playing golf with his brother, according to a pool report.
- A White House official said Biden was briefed on the situation, per a pool report. "The sound resulting from the authorized DOD aircraft was faint at JBA," the official added.
- U.S. Secret Service spokesperson Steven Kopek said in an emailed statement Sunday evening that the incident had no impact on its operations.
What they're saying: The North American Aerospace Defense Command said in an emailed statement Sunday evening that the civilian aircraft was intercepted at about 3:20pm ET.
- "The NORAD aircraft were authorized to travel at supersonic speeds and a sonic boom may have been heard by residents of the region," per the NORAD statement.
- "During this event, the NORAD aircraft also used flares — which may have been visible to the public — in an attempt to draw attention from the pilot," the statement said.
- "The pilot was unresponsive and the Cessna subsequently crashed near the George Washington National Forest, Virginia," NORAD added. "NORAD attempted to establish contact with the pilot until the aircraft crashed."
Meanwhile, the U.S. Capitol Police said in an emailed statement Sunday evening that its officials worked closely with federal partners to "monitor an unresponsive pilot" who was flying an airplane near the National Capital Region.
- "The U.S. Capitol Complex was briefly placed on an elevated alert until the airplane left the area," the statement added.
What's next: The FAA and NTSB are working to determine what caused the Long Island, New York-bound Cessna Citation 56o to crash after it left Elizabethton, Tenn.
- The NTSB said in an emailed statement Sunday night that investigators would request radar data, weather information and maintenance records as part of the investigation.
- "NTSB investigators will look at the human, machine and environment as the outline of the investigation," the statement said.
Between the lines: A sonic boom is "an impulsive noise similar to thunder," according to the U.S. Air Force.
- "It is caused by an object moving faster than sound — about 750 miles per hour at sea level," per the Air Force.
- Sonic booms can shatter glass, but the threat to communities is low.
Editor's note: This article has been updated with new details throughout.