Updated

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."

NASCAR spokesman Ramsey Poston said NASCAR has worked with aviation industry experts "to improve our safety management systems so as to prevent an accident like this from occurring in the future."

Investigators said the pilot who flew that Cessna the day before the crash turned off the radar system and pulled its circuit breaker in midflight he began smelling a burning odor. After flying safely for another hour or so, the pilot submitted an incident report to NASCAR's maintenance division.

But NASCAR did not inspect the problem before the plane was allowed back in the air on July 10.

The pilot in charge that day was told of the incident before he took off and should have investigated further, investigators said. But he may have believed the radar system was simply broken and could have reset the circuit breaker.

About one-third of the way into the 100-mile trip, an electrical problem recurred. The pilot reported smoke in the cockpit minutes before going down. Investigators later found extensive evidence of an electrical fire on board.

Investigators said NASCAR kept poor records of maintenance problems with its planes and had no system for ensuring that reports were addressed or tracked. NASCAR couldn't provide a copy of the incident report submitted the day before the crash, for example.