A United Airlines turboprop commercial airliner crashed in clear weather near Parrottsville, Tennessee on July 9, 1964. Observers noticed a trail of smoke coming from beneath the plane as it flew low over the rural Tennessee mountains. The Viscount 745D smashed directly into a hillside before it exploded and burned. The area was so remote that a road was cut into the hill gradient by recovery workers. This made the region more accessible to teams of investigators seeking an explanation for the disaster. 35 passengers and four crew members died on Flight 823.