(CNN) -- When NASCAR team owner Jack Roush crashed his plane at an Oshkosh, Wisconsin, airport Tuesday night, the aircraft "cartwheeled" an undetermined number of times and ended up facing the opposite direction, National Transportation Safety Board spokesman Peter Knudson said Wednesday.
Knudson said upon landing, the Beechcraft Premier jet, registered to Roush Fenway Racing LLC, rolled "hard to the right," then its right wing dropped "way down" and struck a grass strip, and the plane flipped over at least once. The jet ended up facing north, though it had flown in facing south, Knudson said.
The NASCAR owner was piloting the plane, which took off from Detroit, Michigan, Knudson said.
The NTSB is leading the investigation into the accident.
The Experimental Aircraft Association said in a statement Tuesday night that Roush's passenger in the plane was Brenda Strickland of Plymouth, Michigan. Video showed the two of them walking away from the plane, which appeared to be split toward its midsection.
The morning after the incident, Roush remained in serious, but stable, condition at Theda Clark Medical Center in nearby Neenah, Wisconsin, hospital spokeswoman Megan Wilcox said Wednesday.
She said it was "too early" to say how long Roush would remain in the hospital. The facility was keeping details about Roush's injuries private "at the request of his family and racing team," Wilcox said.
However, Roush's racing team released a statement quoting attending physician Dr. Kevin Wasco as saying that Roush's injuries are not life threatening.
Strickland was brought to Oshkosh's Mercy Medical Center, where she was listed in good condition, Mercy spokeswoman Maria Heim said Wednesday.
The Experimental Aircraft Association's annual air show, AirVenture 2010, had just ended for the day at Wittman Regional Airport in Oshkosh when the crash happened at 6:15 p.m., association spokesman Dick Knapinski said.
The accident shut down the airport until its regular 8 p.m. closing time, but the airport re-opened Wednesday morning, according to Knapinski.
He said Roush comes every year and "does presentations as an airplane enthusiast."
Knapinski said Roush owns one of "probably fewer than 200 airworthy" World War II-era P-51 Mustang fighter planes and Roush had been scheduled to give a presentation about his vintage prop plane Tuesday. Roush had also been slated to appear at the air show Wednesday, signing autographs and talking to NASCAR fans at the Ford tent.
"Roush Fenway Racing is NASCAR's largest team operating eight motorsports teams. Four in the NASCAR Sprint Cup Series with drivers Matt Kenseth, Greg Biffle, Carl Edwards and David Ragan; and four in the Nationwide Series with Edwards, Ricky Stenhouse Jr., Colin Braun, Brian Ickler, and Paul Menard," said the statement from Roush's racing team.