One of auto racing's most successful dynasties was in mourning after a plane owned by Hendrick Motorsports (search) crashed in thick fog en route to a NASCAR (search) race, killing all 10 people aboard, including the son, brother and two nieces of owner Rick Hendrick (search).

The Beech 200 King Air (search) took off from Concord, N.C., and crashed Sunday in the Bull Mountain area seven miles from the Blue Ridge Regional Airport in Spencer, near the Martinsville Speedway (search), said Arlene Murray, spokeswoman for the Federal Aviation Administration (search).

"It's just very tough," said Donnie Floyd, an employee of Hendrick, who placed a bouquet of flowers outside the company's Charlotte, N.C., headquarters. "We are like one big family."

News of the crash halted Hendrick driver Jimmy Johnson's victory celebration after the Subway 500 in Martinsville as news of the deaths filtered through the Hendrick team, which also includes drivers Jeff Gordon (search), Terry Labonte (search) and Brian Vickers (search).

The cause of the crash was not immediately known, but it occurred in rough, hard-to-reach terrain in weather described as "extremely foggy" by Dale Greeson, who lives about a mile from the site.

Hendrick Motorsports issued a statement late Sunday asking "that those affected be kept in your thoughts and prayers, and respectfully requests that privacy be considered throughout this difficult time."

National Transportation Safety Board (search) investigators were to begin their investigation Monday. It was the second major plane accident in less than a week: On Tuesday, 15 people died when a commuter plane crashed and burned as it carried doctors and other medical professionals to a conference in Missouri.

Hendrick employs 460 workers at its North Carolina compound, which includes race shops and a 15,000-square-foot museum and team store. Flowers were placed on shrubs leading into the compound.

The tragedy came on what was to be a triumphant day for the company, with Johnson winning his series-best sixth race and Gordon rallying from a poor start to finish ninth and move into second place in the championship standings.

NASCAR officials learned of the accident during the Subway 500 but withheld the news from the Hendrick drivers until afterward, NASCAR spokesman Jim Hunter said.

NASCAR drivers reacted with a familiar sadness. Series stars Davey Allison and Alan Kulwicki were killed in separate air crashes in 1993.

"I was hoping I'd never hear this," NASCAR driver Mark Martin told the Speed Network after the race. Martin's father, stepmother and half sister died in 1998 when a private plane his father was piloting crashed in Nevada. "I just feel so bad it's unreal," said Martin, himself a pilot.

Driver Rusty Wallace, also a pilot, said he considered the airports in Talladega, Ala., and Martinsville the two most dangerous facilities to fly into for races.

Hendrick has been on a season-long celebration of its 20th anniversary in NASCAR's top series. The organization has won five titles in the top series, three truck series championships, and one Busch series crown.

The team has more than 100 Cup series wins, making Rick Hendrick just the second team owner in NASCAR's modern era to surpass that mark. He's also viewed as a pioneer for beginning the movement to multicar teams in the 1990s.

Hendrick Motorsports identified the dead as: Ricky Hendrick, Rick Hendrick's son; John Hendrick, Rick Hendrick's brother and president of Hendrick Motorsports; Kimberly and Jennifer Hendrick, John Hendrick's 22-year-old twin daughters; Joe Jackson, an executive with DuPont; Jeff Turner, general manager of Hendrick Motorsports; Randy Dorton, the team's chief engine builder; Scott Lathram, a pilot for NASCAR driver Tony Stewart; and pilots Richard Tracy and Elizabeth Morrison.

Ricky Hendrick began his career driving a Busch car for his father, but retired in 2002 because of a racing-related shoulder injury. His father then made him the owner of the Busch car Vickers drove to the series championship last season, and was grooming him for a larger role.

Rick Hendrick pleaded guilty in 1997 to a single count of mail fraud involving the payment of $20,000 to a Honda executive. He was fined $250,000, but avoided jail time because he was battling a near-fatal case of leukemia. He was later pardoned by former President Clinton.

Joe McGovern, a racing fan from Concord, N.C., drove by the team's compound to pay his respects. "It's just devastating," he said. "This was just a great racing team and they are also such nice people."