A plane carrying nine members of a skydiving group that was holding its annual camp-out crashed shortly after takeoff today, killing all the passengers and the pilot, authorities said.

The plane, a twin-engine Beech King Air 200, came down less than a mile from Marine City Airport at 8:20 a.m. in this township about 40 miles north of Detroit, said State Police Sgt. Craig Nyeholt.

Jim Silliman, the National Transportation Safety Board investigator in charge, said the cause was not known but that heat could have been a factor. High temperatures and humidity make it harder for planes to take off, NTSB spokesman George Black said. It was humid today with temperatures in the 80s.

All the passengers were members of the Parahawks, a skydiving group that apparently had gathered at the airport for its three-day annual pig roast and camp-out.

"This is a very extended family," said James Relken, the local Red Cross chapter director, who was at the crash site counseling families of the victims. "The immediate family may not be here, but they're extended family to each other. That's very evident."

John Sers, who said he was the brother of one of the victims, said the Parahawks jumped weekly.

"This is where my brother loved to be. This is his passion. That's what he loved to do," said Sers, who declined to give his brother's name. "If you've got to die doing something, it ought to be something you have a passion for."

Raymond Wilson said his 22-year-old nephew, Roger Engle III, had made more than 100 jumps and was also an expert at parachute-packing.

"He was out here all the time. He jumped a whole lot. We were hoping that he wasn't [on the plane], but his grandpa knew he was," Wilson said.

The plane's pilot, Paul Myks, flew DC-9s for Spirit Airlines, said Gary Cooper, regional director of the U.S. Parachuting Association.

Macomb County Medical Examiner Werner Spitz said the plane, which reportedly crashed shortly after takeoff, broke into three parts and that the victim's bodies were spread across a 50-yard area of wreckage.

Robert Franz, who lives near the airport, said he heard the plane taking off -- then the engine went dead. A second or two later, he said, there was a loud crash.

Mike Miller, 45, and his son Dustin were sitting in their living room when they saw the plane coming toward the airfield.

"Planes come in and out all the time. But this one was a sharp bank that was more than usual. We could see the bottom of the plane," he said.

Said Dustin: "It was coming in awfully fast. I heard a crunching sound like a can being crunched. Then the ground shook a little and we saw the black smoke and called 911."