Investigators on Wednesday blamed NASCAR for a ‘‘tragic, unnecessary’’ plane crash in 2007, saying the racing organization let one of its aircraft take off without checking an electrical problem reported the day before.

NASCAR violated federal aviation rules when it allowed the small corporate plane back in the air on July 10, 2007, the National Transportation Safety Board said.

The Cessna 310 was en route from Daytona Beach to Lakeland in Florida when it crashed outside Orlando. The plane hit two homes, killing a 24-year-old law student and her 6-month-old son as well as a 4-year-old neighbor. Also killed were the NASCAR pilot and the husband of a NASCAR executive, a pilot himself.

The safety board also said the crash resulted partly from sloppy maintenance record-keeping at NASCAR’s aviation unit. The organization has a fleet of planes comparable to a small charter operation or a tiny airline.

‘‘I think we’re going to find that this accident started before the airplane even left the ground,’’ said one board member, Robert Sumwalt said. He said NASCAR ‘‘enabled this tragic, unnecessary crash.’’