A preliminary National Transportation Safety Board accident report says nothing broke off a 1950s-era plane prior to it crashing into the ground during a West Virginia air show last month and killing the pilot.
The board also says a review of video and still digital images depicting the bottom of the airplane immediately before the accident did not reveal any open panels.
Thursday's report did not specify a cause for the Sept. 17 crash in Martinsburg.
Pilot John Mangan of Concord, N.C., was killed in the crash of his North American T-28 C during an acrobatic roll. There had been no sign of trouble before the plane plunged to the ground and exploded.
The accident came a day after an air race crash in Reno, Nev., that killed 11 people.