(DAYTON)-- A preliminary report from the National Transportation Safety Board says a wing walker and aerobatic pilot killed in a fiery crash at the Vectren Air Show near Dayton practiced their performance the previous day and reported no mechanical problems.

The June 22 crash was witnessed by thousands of horrified spectators and captured on video.

The preliminary accident report says the plane was turned upside down and positioned to cross in front of the crowd when the nose pitched slightly and the plane abruptly rolled and struck ground. Federal Aviation Administration records showed clean safety records for the 64-year-old pilot, Charlie Schwenker, and 44-year-old performer Jane Wicker.

Both Schwenker and Wicker, were from Virginia. The report does not address the cause of the crash.