In this Oct. 16, 2011 file photo, Drivers crash during a wreck that involved 15 cars during the IndyCar Series' auto race at Las Vegas Motor Speedway in Las Vegas. Driver Dan Wheldon was airlifted to a hospital. Will Power (12), of Australia, is airborne at left.

AP Auto Racing Writer — IndyCar officials plan to announce Thursday their initial findings from the investigation into Dan Wheldon's fatal accident.

Wheldon was killed in the opening laps of the Oct. 16 season finale at Las Vegas Motor Speedway. The two-time Indianapolis 500 winner was involved in a 15-car accident, and his car sailed into the catchfence.

Many elements of the event have been criticized in the wake of the accident, and IndyCar hasn't released its 2012 schedule as officials wait for the results of the investigation. One of the issues they hope will be addressed is if the IndyCar is compatible with high-banked ovals.

The series came to an agreement last week with Las Vegas to buy its way out of the portion of the contract that called for IndyCar to end 2012 at Las Vegas. A possible return in 2013 for the final year of the contract will be addressed a later date, and after at least one test session at the track.

But what the report will likely show is that a combination of factors — a perfect storm, per se — led to Wheldon's death.

The entire event has been heavily scrutinized in the wake of Wheldon's accident. Critics have questioned everything from the speeds at Las Vegas, to the season-high 34-car field and the varying degrees of experience among the drivers in the race.

There also have been questions about Wheldon's participation.

Wheldon was making just his third start of the season and chasing a $5 million incentive offered by series CEO Randy Bernard to any non-IndyCar regular who could drive from the back of the field to win the race. Allowing Wheldon to take the challenge was a stretch — he won 14 races on ovals, including the Indy 500 earlier last season — but because he sat out the season, he technically qualified for the bonus.

But Wheldon felt he was up for the challenge.

He was the in-race reporter for ABC during the event, and spoke with the announcers during the warm-up laps. In a brief interview, Wheldon defended his participation and the entire IndyCar Series.

"I wouldn't be doing this if I didn't think that I could win," he said from his car. "Certainly I am not underestimating the talent of the other drivers in the field. I think IndyCar has got a phenomenal field right now."

Then asked about speeds that had exceeded 220 mph in practice sessions, Wheldon predicted a hairy race but noted the importance the event had on the upcoming 2012 season. Bernard had worked tirelessly to build an impressive finale in hopes it would give IndyCar momentum for next season, when a new car will be introduced with three engine manufacturers.

" Absolutely, I think they (the speeds) will be a little bit faster. This is going to be a spectacle," Wheldon said. "This is a great race to go out for the IndyCar Series in 2011. We know we've got the new cars and multiple engine manufacturers coming for 2012, so we're excited and grateful for Honda for sponsoring this particular race."

Wheldon was killed minutes later when the crash began ahead of him at the start of the 12th lap. He had picked his way through the field and gained at least 10 spots when he came upon the accident and had nowhere to go to avoid the spinning cars and flying debris.

IndyCar has been at a crossroads since the accident.

Drivers have openly questioned the series racing on high-banked ovals, and Bernard has struggled to fill in the gaps on his 2012 schedule. He's also behind on tightening the rule book, a project he had hoped to have completed within a few weeks of the season ending, and he's yet to find a suitable replacement for race director Brian Barnhart, who had the duty stripped from him last month.

Then there's the issues facing the new car, which Wheldon helped develop.

Although it's proved decent during road-course tests, the car is slower than expected on ovals and drivers have complained about its handling and poor weight distribution. Much of the hype around the series surrounded the new car, which has been billed as safer and a technical upgrade.

Now, teams are waiting for manufacturer Dallara to make costly changes to the suspension in hopes of improving its oval performance.

The first scheduled oval race is the Indianapolis 500 in May.