JOHNSTOWN, Pa. - A new video shows a cloud of grey smoke rising in the sky minutes after United Airlines Flight 93 crashed in western Pennsylvania on Sept. 11, 2001.

The Tribune-Democrat newspaper of Johnstown says the video was filmed and narrated by Somerset County resident Dave Berkebile, who died this year.

Berkebile calmly reports a plane has crashed a few miles (kilometres) from his Berlin home and assumes a link to the other terror attacks that day.

Donna Glessner is collecting oral histories for the National Park Service. She believes the video is the earliest footage of the crash in Shanksville, a rural area southeast of Pittsburgh.

Flight 93 crashed as passengers fought four hijackers. Investigators believe the plane was going 580 mph (935 kph) upon impact.

Forty passengers and crew members perished.