What happened
On July 9, 1964, at approximately 18:15 e.s.t., a Vickers Viscount 745D, registration N7405, crashed northeast of Parrottsville, Tennessee. The aircraft, operated by United Air Lines, Inc., was performing a scheduled flight from Philadelphia, Pennsylvania, with planned stops in Washington, D.C., and Knoxville, Tennessee, before its final destination of Huntsville, Alabama.
Prior to the accident, the flight proceeded without any documented mechanical issues or operational difficulties. However, around 18:10 e.s.t., observers noted the aircraft flying at a low altitude while emitting smoke. As the plane traveled southwest, a passenger was seen falling from the fuselage roughly 1.6 nautical miles from the crash site, followed shortly by a cabin window. The aircraft subsequently entered a nose-high attitude before the left wing and nose pitched downward, leading to a high-speed impact with the ground. The collision resulted in an explosion and intense fire.
The accident resulted in 38 fatalities, comprising all four crew members and 34 passengers, plus one additional passenger who succumbed to injuries after falling from the plane. The wreckage sustained total destruction due to the force of the impact and subsequent fire.
Findings
Investigations concluded that an uncontrollable in-flight fire originated within the fuselage. The origin of this fire could not be determined, but the blaze led directly to the loss of control over the aircraft.